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Table of Content
10 March 2024, Volume 43 Issue 3
    Chemical processes and equipment
    Research progress of cyclic distillation technology
    YANG Chenyang, ZHU Huaigong, CAI Wangfeng, ZHANG Minqing, WANG Yan, ZHANG Ying, CHEN Jianbing
    2024, 43(3):  1109-1117.  doi:10.16085/j.issn.1000-6613.2023-0469
    Abstract ( 33 )   HTML ( 3)   PDF (3110KB) ( 43 )  
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    Under the “carbon peaking and carbon neutrality” goals, process intensification is one of the key technologies for achieving green production. Cyclic distillation, a new distillation technology based on the process intensification theory, utilizes specific tower internals and control schemes to change the flow mode of gas and liquid phase in the traditional distillation column and achieves periodic separate phase movement (SPM) of gas and liquid phases, offering advantages such as high processing capacity, low energy consumption, and excellent separation performance. Compared with traditional distillation operations, the Murphree efficiency of cyclic distillation technology can be increased to 140%—300%, and energy consumption can be reduced by 20%—30%. This article provided a brief overview of the research of background, working principle, industrial applications, and two special trays (Maleta tray and COPS tray) of cyclic distillation technology. The paper summarized the control methods and tower internals of cyclic distillation columns and proposed the prospective development of cyclic distillation technology.

    Research progress on failure prediction and prevention technology of non-metallic pipes in oil and gas fields
    ZHANG Yuhong, LI Xuanyu, FENG Chunjian, MA Chunxun, ZHANG Chen, ZHOU Yangyang, BI Haisheng
    2024, 43(3):  1118-1132.  doi:10.16085/j.issn.1000-6613.2023-0452
    Abstract ( 7 )   HTML ( 0)   PDF (2567KB) ( 4 )  
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    The corrosion and perforation risk of metal pipes in oil and gas fields is becoming more and more serious, and pipeline leakage accidents often occur. Non-metallic pipes such as glass steel pipe, steel skeleton reinforced polyethylene composite pipe and flexible composite pipe are gradually favored in oil and gas field development and production system for their good corrosion resistance and applicability. However, due to the aging effects of internal and external pressure load and medium corrosion during the long-term service of the pipe, various failure problems such as matrix cracking, pipe body brittle, fiber/matrix interfacial debonding, interlayer separation and so on need to be solved urgently. Based on this situation, this paper summarized the characteristics, application and failure causes of non-metallic pipelines commonly used in oil and gas fields, as well as the detection and positioning, non-destructive testing technology, risk assessment and life prediction methods of non-metallic pipelines, and put forward relevant suggestions on the prevention of non-metallic pipeline damage and failure in pipeline manufacturing, construction, operation, application, maintenance and key technologies. The paper also prospected the key issues of non-metallic pipeline failure prevention technology to provide effective support for the relevant research of non-metallic pipeline failure prediction methods and prevention and control technologies.

    Characteristics analysis of gas solid two-phase flow in pneumatic conveying based on CFD-DEM algorithm
    YU Yanfang, SHI Bowen, MENG Huibo, DING Pengcheng, YAO Yunjuan
    2024, 43(3):  1133-1144.  doi:10.16085/j.issn.1000-6613.2023-0353
    Abstract ( 13 )   HTML ( 1)   PDF (4458KB) ( 15 )  
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    Because of its light weight, ultra-light powder particles are easily disturbed by airflow in the process of transportation, and the pipeline pneumatic conveying process of material is unstable and prone to blockage. To study the gas-solid two-phase flow characteristics of ultra-light powder particles in cyclone pneumatic conveying, computational fluid dynamics and discrete element method (CFD-DEM) were used to simulate the gas-solid two-phase flow characteristics in Komax static mixer. It was found that the horizontal pipe with Komax elements can change the particles flow state, and improve the accumulation and uneven distribution of particles. From the analysis of the flow state of particle phase and fluid phase, it was concluded that the element aspect ratio Ar=3 was the preferred geometry structure. Through the range analysis of orthogonal experiments, the order of factors affecting gas-solid two-phase flow characteristics was obtained as follows: conveying gas velocity > particle mass flow rate > particle size. When the element aspect ratio Ar was 3, the collision frequency and strength of particle-particle and particle-wall were negatively correlated. Combining with the dispersion state of the particle flow at the outlet, the optimal conveying gas velocity was 3—4m/s. Considering the influence of conveying gas velocity on pressure drop in the pipeline, the empirical fitting formula of pressure drop, conveying gas velocity and axial position during pneumatic transportation of horizontal pipeline with Komax element was proposed.

    Heat transfer enhancement of non-Newtonian fluid in the blade-type static mixer
    YU Yanfang, DING Pengcheng, MENG Huibo, SHI Bowen, YAO Yunjuan
    2024, 43(3):  1145-1156.  doi:10.16085/j.issn.1000-6613.2023-0375
    Abstract ( 7 )   HTML ( 1)   PDF (6128KB) ( 10 )  
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    Non-Newtonian fluids play a key role in chemistry, food, materials, and other fields. They usually have low heat transfer performance due to the high apparent viscosity. The blade-type static mixers have distinctive technical characteristics in chemical process intensification as a kind of efficient heat transfer enhanced equipment. The flow and heat transfer characteristics of non-Newtonian fluids in Kenics (KSM) and Lightnin static mixers (LSM) were compared. The effects of volume flow rate, aspect ratio and solution concentration on the flow and heat transfer of carboxy-methyl cellulose (CMC) power-law fluids were analyzed. The results showed that the higher volume flow rate of CMC solution contributed to the higher heat transfer coefficient and pressure drop. The static mixing elements significantly enhanced the heat transfer coefficient and pressure drop, and the influence of Lightnin was more obvious. The aspect ratio of the elements and the concentration of the CMC solution also affected the fluid flow and heat transfer. The heat transfer performance was improved with the decreasing aspect ratio, while the comprehensive heat transfer performance coefficient (PEC) decreased because the influence of increased friction coefficient was dominated. The increase of solution concentration gradually weakened the heat transfer capacity and significantly increased the pressure drop thus the comprehensive heat transfer performance decreased. It was concluded that the KSM with aspect ratio of 3.0 had the highest PEC which was 2.114 when the volume flow rate was 4.5×10-4m3/s and the solution concentration was 0.374%.

    Effect of polyacrylamide on flow characteristics of highly viscous oil-water annular flow
    YIN Xiaoyun, LI Jing, LIN Dong, HU Jinyan, ZHANG Liang, JING Jiaqiang, KARIMOV Rinat M, SUN Jie
    2024, 43(3):  1157-1166.  doi:10.16085/j.issn.1000-6613.2023-0420
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    Aiming at the problem of flowability improvement of water annulus for heavy oil transportation in water ring, a simulation experiment method for heavy oil flow boundary layer under the action of water ring with anionic polyacrylamide (PAM) was proposed. On the basis of self-developed design of indoor visualization experimental loop device of heavy oil-water two-phase flow, taking 500# industrial white oil as simulated oil sample of Lyuda highly viscous oil, the flow regime characteristics and friction resistance properties of heavy oil-water annular flow before and after the addition of PAM in outer aqueous phase were investigated experimentally. The synergistic drag reduction effect of PAM on water ring lubrication was evaluated, and the mechanism of PAM on flow stability of water ring was analyzed. The experimental results showed that the presence of PAM had a significant effect on the flow pattern and resistance characteristics of heavy oil-water annular flow. After the addition of PAM, the region of annular flow reduced and changed to either stratified flow or plug flow, and when it transformed into stratified flow, the drag reduction effect of PAM was lost. As the oil superficial velocity varied from 0.23m/s to 0.90m/s, with the raise in water volume fraction, the drag reduction rate first increased rapidly and then decreased slowly. The maximum drag reduction rate in the test range reached 35%. The research results could provide a theoretical guidance and technical support for the technology optimization of heavy oil-water ring transportation, as well as a new concept and method for the flow improvement of heavy oil pipeline transportation.

    Scheduling algorithm for refinery crude oil storage and transportation based on SAC
    MA Nan, LI Hongqi, LIU Hualin, YANG Lei
    2024, 43(3):  1167-1177.  doi:10.16085/j.issn.1000-6613.2023-1498
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    Currently, most refinery crude oil scheduling studies adopt static scheduling schemes based on mathematical programming, which cannot adjust and optimize according to environmental change in real-time. This paper established a dynamic real-time scheduling decision model subject to refinery production constraints and designed the corresponding agent interaction environment. The soft actor-critic (SAC) algorithm in deep reinforcement learning solved the model. Firstly, the crude oil resource scheduling problem was transformed into a Markov decision process, and a deep reinforcement learning algorithm based on SAC was proposed to simultaneously determine discrete decisions such as transmission target and continuous decisions such as transmission speed in the scheduling process. Extensive experimental results showed that the strategy learned by the algorithm has better usability, which effectively improved the decision-making efficiency of the algorithm and effectively controlled the influence range of random events on the overall decision-making compared with the baseline algorithm. This algorithm can provide new ideas for rapid decision-making of crude oil storage and transportation scheduling in coastal refineries.

    Energy processes and technology
    Research progress on optimization of large temperature-lift vapor compression heat pump system
    WU Fengming, LI Shuaiqi, HE Shihui, SONG Wenji, FENG Ziping
    2024, 43(3):  1178-1198.  doi:10.16085/j.issn.1000-6613.2023-0401
    Abstract ( 5 )   HTML ( 0)   PDF (2793KB) ( 8 )  
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    In the context of the “carbon peaking and carbon neutrality” strategy, large temperature-lift heat pump technology can not only save energy in low carbon, but also effectively utilize lower grade heat energy to develop into higher temperature field. In this paper, the research progress of performance optimization of large temperature-lift vapor compression heat pump system (large temperature-lift system) is summarized, and the feasible optimization means of large temperature-lift system are analyzed from refrigerant, component, cycle optimization and demonstration verification. Currently, the commonly used refrigerants in practical engineering of large temperature-lift systems are still mainly high GWP value refrigerants such as R134a and R245fa; in terms of screening refrigerants with high temperature-lift, carbon dioxide (R744) in natural pure refrigerants has a wide temperature range and excellent performance; water (R718) is one of the potential refrigerants for breaking through the ultra-high temperature (150℃) limit in large temperature-lift systems; organic pure refrigerants have developed rapidly, with R1234ze(Z) and R1336mzz(Z) having extremely low GWP values and excellent thermodynamic properties; the preparation of R32-based, HFOs- based, and CO2-based mixed refrigerants with low GWP values is currently a promising approach. In terms of component optimization, mature technologies such as compressor frequency conversion technology provide current solutions for optimizing components of large temperature-lift systems; the industrial products of magnetic bearing technology are becoming mature, which can effectively reduce the friction loss of large temperature-lift system; new component optimization ideas are provided by emerging technologies such as line structure heat exchanger technology for large temperature-lift system. In terms of cycle optimization, mature technologies such as vapour/liquid injection and multi-stage compression provide current schemes for loop optimization of large temperature lift system; the ejector technology and vortex tube technology have optimization effects on large temperature-lift systems, but are limited by the lack of engineering practical experience and unclear mechanism research. According to the demonstration and verification section, the technology of vapour injection is currently the most widely applicable and mature optimization technology for large temperature-lift systems in industrial application, and under certain conditions, it can increase the coefficient of performance value of large temperature lift systems by more than 20%; series multi-stage compression technology and cascade compression technology are powerful means to increase the temperature-lift range of the system and ensure low-temperature heating.

    Promotion of HCFC-141b hydrate production by lactone sophorolipids
    HUANG Meng, SUN Zhigao, XU Wenchao, ZHANG Huanran, YANG Yang
    2024, 43(3):  1199-1205.  doi:10.16085/j.issn.1000-6613.2023-0333
    Abstract ( 2 )   HTML ( 1)   PDF (1415KB) ( 0 )  
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    Cold storage air conditioning is an important method to reduce peak-valley difference of power grid and realize peak regulation of the load side of power grid. Refrigerant hydrate as a cold storage medium has the advantages of high cold storage density and high phase change temperature. HCFC-141b refrigerant is a potential cold storage medium. In order to promote the formation of HCFC-141b refrigerant hydrate, the green environmental sophorid glycolipid was selected as a promoter to improve HCFC-141b hydrate formation. The experimental results showed that the addition of lactone sophorolipids could greatly shorten the induction time of HCFC-141b hydrate formation. The mass fraction of sophora sophorolipid affects the nucleation and growth process of hydrate. 0.5% was the optimal concentration of lactone sophorolipid to improve hydrate formation, where the average induction time of HCFC-141b hydrate formation was the shortest (about 153min). Experimental results also showed that hydrate formation is random. The addition of lactone sophorolipids could reduce the randomness of hydrate production. The standard deviation of induction time of hydrate formation with 0.5% lactone sophorolipids was smallest in this work, which showed the system with 0.5% lactone sophorolipids could steadily nucleate. The addition of lactone sophorolipids would affect the cold storage capacity of HCFC-141b hydrate. When 0.5% lactone sophorolipids were added, the average cold storage capacity of HCFC-141b hydrate reached 232.45kJ/kg.

    Heat charge and release characteristics of household off-peak electricity thermal storage heating system
    YIN Shaowu, LI Xianxian, HAN Jiawei, LU Ming, TONG Lige, WANG Li
    2024, 43(3):  1206-1213.  doi:10.16085/j.issn.1000-6613.2023-0335
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    A household off-peak electricity thermal storage heating system (HOETSHS) based on phase change material (PCM) was proposed. Its heat storage/release characteristics and heating performance were comprehensively explored through numerical simulation and experiments. Fluent was used to numerical simulation of the heat release process of HOETSHS. The effect of inlet air velocity, inlet temperature and thermal storage materials on the heat release performance of the thermal storage heating system were studied. The correctness of the simulated working condition was verified by experimental research. The results suggested that the inlet air velocity had a significant effect on the heat release performance of the system. As the inlet air velocity increased, the average outlet temperature of the system decreased, and the immediate heating load increased. However, the effect of the inlet temperature on the heat release performance of the system was relatively weak. Composite phase change material (CPCM) was more suitable as heat storage medium for the phase change thermal storage heating system than pure ammonium aluminum sulfate dodecahydrate due to its higher thermal conductivity. The HOETSHS had good heat storage and release capacity, which can make a useful reference for the utilization of latent heat storage in off-peak power.

    Analysis of the heat storage performance of the latent heat storage unit combined with frustum wavy tube
    DING Lihua, XU Hongtao, ZHANG Chenyu
    2024, 43(3):  1214-1223.  doi:10.16085/j.issn.1000-6613.2023-0394
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    In order to improve the heat storage performance of latent heat storage unit (LHSU), three novel heat transfer tubes of the LHSUs were proposed, including frustum, wavy, and frustum wavy heat transfer tube LHSUs. Based on the numerical simulation, the heat storage performance of the cylindrical heat transfer tube latent heat storage unit (C-LHSU) and the above three novel LHSUs were compared. In addition, the influence of the tilt angle of the heat transfer tube on heat storage performance was studied for the LHSU with the frustum wavy tube (FW-LHSU). The results showed that the three novel tube structures could enhance heat storage performance, and the FW-LHSU had the optimal heat storage performance. Compared with C-LHSU, FW-LHSU had a 32.64% reduction in melting time and a 48.1% enhancement in heat storage density. The heat storage performance of FW-LHSU could be further improved by increasing the tilt angle of the heat transfer tube. When the tilt angle of the heat transfer tube increased from 2° to 8°, the heat storage time of FW-LHSU decreased by 37.00%, and the heat storage density increased by 48.44%, respectively.

    Performance of a vertical thermally regenerative ammonia-based battery with a high-concentration ammonia chamber
    LU Zhiqiang, SHI Yu, CHEN Pengyu, ZHANG Liang, LI Jun, FU Qian, ZHU Xun, LIAO Qiang
    2024, 43(3):  1224-1231.  doi:10.16085/j.issn.1000-6613.2023-0417
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    Thermally regenerative ammonia-based battery (TRAB) can effectively convert low-temperature thermal energy into electricity, but its serious ammonia crossover phenomenon seriously affects the power production stability of the battery. A vertical thermally regenerative ammonia-based battery with a high-concentration ammonia chamber (TRAB-C) was developed based on the phenomenon of ammonia crossover and stratification in this study. The construction of high-concentration ammonia chamber and the block layer of ammonia transfer was applied to adjust ammonia distribution and then alleviate ammonia crossover. At a higher ammonia concentration (≥6mol/L), TRAB-C obtained higher output power, higher total charge, and more stable power generation capacity than a TRAB with a conventional structure because it solved the ammonia crossover by regulating the distribution of ammonia concentration in the anode. In addition, the porous copper foam anode could block the downward transport of ammonia to alleviate ammonia crossover further. A porous electrode with appropriate pore density (80PPI) induced a large electrode surface area and favorable mass transfer inside the electrode, contributing to the maximum power (10.8mW) of TRAB-C.

    Performance of electrochemical reduction of CO2 by superaerophilic copper foam electrode with nanowires
    WANG Kai, YE Dingding, ZHU Xun, YANG Yang, CHEN Rong, LIAO Qiang
    2024, 43(3):  1232-1240.  doi:10.16085/j.issn.1000-6613.2023-0426
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    Electrochemical reduction of CO2 by renewable electricity is regarded as a promising method to storage energy and reduce emissions environmental problems. However, the hydrogen evolution side reaction at the cathode will reduce the performance of electrochemical reduction of CO2. Nanowires were prepared on the copper foam electrode to expand the electrochemical active area of the electrode. Then, the copper foam nanowire electrode was treated with trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane to make the electrode surface change from aerophobic to aerophilic, which was expected to strengthen the mass transfer of gas-phase CO2, increase the three-phase contact line of the reaction and further improve the performance of electrochemical reduction of CO2. Experimental results showed that compared with the copper foam nanowire electrode without aerophilic treatment, although the prepared aerophilic electrode possessed lower electrochemical active area, its superaerophilic property was conducive to the mass transfer of CO2, inhibited the transport of H+ in electrolyte and weakened the hydrogen evolution side reaction. As a result, the H2 Faraday efficiency dropped by 17.7% at -1.5V (vs. Ag/AgCl) and the performance of electrochemical reduction of CO2 was improved.

    Heat transfer performance simulation and optimization of deep borehole heat exchanger array
    CHEN Hongfei, YANG Fuxin, TAN Houzhang, CAO Jingyu, WU Shengyuan
    2024, 43(3):  1241-1251.  doi:10.16085/j.issn.1000-6613.2023-0501
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    In the application of the deep borehole heat exchanger (DBHE), the pipe array is composed of multiple DBHEs and used for the building heating. In order to study the heat transfer performance of the coaxial DBHE array, a numerical model was established based on the typical geological distribution in Xixian New Area. The influence of the distance between the DBHEs and their distribution patterns was investigated on the thermal interaction and the attenuation of outlet-water temperature during the long-term heating period. The results showed that the ‘cold accumulation’ of rock and soil around the DBHE was the main reason for the decline of the heating capacity of the DBHE array year by year. When the distance between the DBHEs increases from 5m to 25m, the average outlet-water temperature of the DBHE and the heat extraction power increased by 3.86% and 11.5%, respectively. Considering the geological distribution in Xixian New Area, the distance between the DBHEs should be kept above 15m. In the four types of DBHE array distributions (cross, circular, polyline, linear), the straight-line distribution exhibited the smallest attenuation in outlet-water temperature and heat extraction power. The outlet-water temperature of the central DBHE only decreased by 5.74%. In the engineering applications, it is necessary to avoid the overlapping arrangement of DBHEs and ensure that they are arranged in a straight line.

    Industrial catalysis
    Research advance of heterogeneous catalytic system for the coupling between CO2 and epoxide into propylene carbonate
    LIU Fangwang, HAN Yi, ZHANG Jiajia, BU Honghong, WANG Xingpeng, YU Chuanfeng, LIU Mengshuai
    2024, 43(3):  1252-1265.  doi:10.16085/j.issn.1000-6613.2023-0351
    Abstract ( 15 )   HTML ( 0)   PDF (2675KB) ( 22 )  
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    As the most important greenhouse gas, carbon dioxide (CO2) has caused serious environmental problems by excessive emission. On the other hand, CO2 is an abundant, cheap, safe and renewable C1 resource, and thus is considered as an ideal carbon material in organic synthesis. Efficient and green chemical fixing CO2 to prepare cyclic carbonate with high boiling, high polarity, low volatility and biological degradability is an effective way of CO2 resource utilization, which has attracted wide attention. In this paper, the existing reaction pathways for the synthesis of cyclic carbonate are briefly described. Then, staring with the coupling reaction of CO2 with epoxides, we emphatically analyze the reaction mechanism, and the design ideas and current research advance of the heterogeneous catalytic system. Meanwhile, the advantages and disadvantages of the catalytic parameters such as catalytic conditions, catalytic activity and recyclability, of different heterogeneous catalytic systems are comprehensively compared. Finally, the application and development prospects of different heterogeneous catalytic systems are summarized and suggested. In the future, heterogeneous catalytic systems should be combined with homogeneous ones, which could efficiently activate CO2 and epoxides under mild conditions by utilizing their advantages.

    Research progress in the catalytic hydrodealkylation of C9+ heavy aromatics
    ZHANG Pengfei, YAN Zhangyan, REN Liang, ZHAGN Kui, LIANG Jialin, ZHAO Guangle, ZHANG Fanbin, HU Zhihai
    2024, 43(3):  1266-1274.  doi:10.16085/j.issn.1000-6613.2023-0410
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    The capacity expansion or new construction of aromatic complex and ethylene cracking plant in China led to a drastic increase in the yield of C9+ heavy aromatics. The conversion of C9+ heavy aromatics to BTX by catalytic hydrodealkylation technology would be conducive to improving economic benefits for refinery. Based on the production of BTX from C9+ heavy aromatics, firstly, the mechanism of carbenium-ion and free radical in the reaction system of catalytic hydrodealkylation was emphasized. Secondly, the progress of the research on the hydrodealkylation process and catalysts in the domestic and foreign was summarized. Thirdly, the advantages and disadvantages of those process and catalysts was analyzed. Finally, the development direction of reaction mechanism, process and catalyst were forecasted. The future development direction of catalytic hydrodealkylation was to increase the production of BTX and simultaneously produce high value-added monomers such as tritoluene and tetratoluene. The research and development of novel catalysts should be combined with specific production objectives and reaction mechanisms, and the catalytic hydrodealkylation catalysts with high reaction activity, high selectivity and high stability should be prepared directionally.

    The role of seed in the synthesis of molecular sieves
    LIANG Yanyan, ZHANG Junliang, GUO Yunya, ZHANG Yanting
    2024, 43(3):  1275-1292.  doi:10.16085/j.issn.1000-6613.2023-0493
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    Molecular sieves have been widely used as catalyst or adsorbent in petroleum refining and fine chemical industries. The synthetic chemistry of molecular sieve has advanced significantly in recent years, and the role of seed crystal in zeolite synthesis has become a research hotspot. Here the research progress of the role of seed in molecular sieve synthesis is reviewed and the impacts of seed are concluded to five aspects: accelerating crystallization rate, broadening the silica to alumina ratios of product, regulating product morphology, substituting organic templates and other functions. The focus is the role of seed crystal in the formation of molecular sieves with special morphology and the substitution of seed for organic template agent. According to the nucleation and growth mechanisms of molecular sieve, the principles of different effects of seed crystal in the synthesis process were analyzed, and it was revealed that the reduction of the activation energy of molecular sieve nucleation by seed crystal was the basis for its different effects. From the perspective of clean production, it is proposed that the specific structural changes of seed crystal in the process of molecular sieve synthesis and the synthesis of molecular sieve with high performance using seed crystal instead of organic template agent will become the focus of future research.

    Modification of Rainey nickel with phosphorus quantum dots and its catalytic hydrodesulfurization performances
    GU Xingpeng, MA Hongqin, LIU Jiahao
    2024, 43(3):  1293-1301.  doi:10.16085/j.issn.1000-6613.2023-0359
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    The emission of high-sulfur fuel combustion will cause great damage to environment and seriously affect the living environment of human beings. It is very important to develop efficient hydrodesulfurization (HDS) catalysts. In this work, Phosphorus quantum dots and commercial red phosphorus were used for the first time to modify the unsupported catalyst (Raney nickel), and the influence of modification conditions (modification temperature, dosage, reaction temperature) on the performance of catalyst hydrodesulfurization (DBT) was systematically explored. The modified catalysts were characterized by BET, XRD, SEM, TEM, EDS and XPS, and their catalytic activity was evaluated for dibenzothiophene (DBT) hydrogenation. The results showed that the HDS performance of Rainey nickel modified with phosphorus quantum dots were greatly improved that could be attributed to the increased pore size of the modified catalyst and the strong interaction between phosphorus quantum dots and nickel. Large pore size was beneficial for the diffusion of DBT molecules, and the positively charged Ni δ+ generated by the interaction with phosphorus quantum dots facilitates the adsorption of DBT, thereby improving the hydrodesulfurization performance of the catalyst. DBT conversion rate of 99.1% was achieved under optimal experimental conditions.

    Optimization of Fe1-x O ammonia synthesis catalyst by BP neural network model
    ZHANG Shuming, LIU Huazhang
    2024, 43(3):  1302-1308.  doi:10.16085/j.issn.1000-6613.2023-0433
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    A prediction model between the content of promoter and the activity of catalyst was established by BP neural network, with which the promoter of Fe1-x O ammonia synthesis catalyst was optimized. Firstly, the preliminary experimental data were summarized into five types of catalysts including three, four, five, six and seven promoters. With the content of the promoters (volume fraction) as the input model variable and the ammonia concentration (reactivity) at the outlet of the reactor at 425℃ as the output one, the formula of the promoter was optimized. The results showed that maximum mean square error of fitting values of BP neural network prediction model was 0.2784, while that of the predicted values was 0.1592, indicating the accuracy of the BP neural network model was high. On the basis of this model, multiple population genetic algorithm was used to search the extreme value, and the optimal catalyst formula was obtained and verified by experiments. The maximum relative error between the measured values of 5 samples prepared according to the optimized formula and the predicted ones was 2.88%. The highest activity was 18.83% for the catalyst containing seven promoters, 1.31% higher than the average reactivity value of the original sample (17.52%), and a relative increase of 7.48%.

    Particle size regulation of HZSM-22 and Pt/HZSM-22 for n-dodecane hydroisomerization
    CHEN Feng, WANG Xuande, HUANG Wei, WANG Xiaodong, WANG Yan
    2024, 43(3):  1309-1317.  doi:10.16085/j.issn.1000-6613.2023-0447
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    ZSM-22 zeolite crystals with different c-axis lengths were synthesized by using supersaturated solution method under static hydrothermal conditions and adjusting the water content in the synthetic solution. The as-synthesized ZSM-22 zeolite crystals were characterized by XRD, SEM, N2 physical adsorption, NH3-TPD and Fourier transformed infra-red spectroscopy of pyridine adsorption(Py-FTIR). By loading Pt on the ZSM-22 zeolite crystals, the Pt/ZSM-22 bifunctional catalysts were prepared, in which ZSM-22 zeolite crystals played the role of acid supports and the 0.5% Pt acts as (de)hydrogenation active sites. The hydroisomerization of n-alkanes was carried out with n-dodecane as the probe molecules. The effect of water content in the zeolite synthesis solution on the hydroisomerization performance of Pt/ZSM-22 catalyst was investigated. The results indicated that the less the water, the smaller the ZSM-22 crystals. However, a few cristobalite and ZSM-5 crystals were formed when the content of water in the synthetic solution was reduced to a certain value. HZSM-22 synthesized in the solution with the molar composition of SiO2∶Al2O3∶K2O∶DEA∶H2O=1∶0.01∶0.08∶0.29∶28 showed the highest medium and strong Brønsted acid amount in the three HZSM-22 samples, and shorter c-axis length. The bifunctional catalyst Pt/HZSM-22 prepared with this kind of HZSM-22 crystals showed the best catalytic performance. The conversion of n-dodecane was 73.24%, the yield of iso-alkanes was 57.92%, and the selectivity of iso-alkanes was 79.09%.Moreover, the selectivity of mono-branched iso-dodecane with methyl branching positioned in the center of the chain, 5-methylundecane, was up to 17.66% at 320℃.

    Catalytic hydrogenation of furfuryl alcohol into pentanediol over Pt/CaO materials
    XIAO Yaoxin, ZHANG Jun, SHAN Rui, YUAN Haoran, CHEN Yong
    2024, 43(3):  1318-1327.  doi:10.16085/j.issn.1000-6613.2023-0448
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    A series of Pt/CaO catalysts were synthesized via impregnation method and applied for the selective hydrogenation of bio-based furfuryl alcohol into pentanediol. The physicochemical characteristics of the as-prepared catalysts were comprehensively characterized through X-ray diffractometer, scanning electron microscopy, CO2-temperature programmed desorption, N2 isothermal adsorption-desorption, X-ray photoelectron spectroscopy, and thermogravimetric-differential thermal analysis. The experimental results showed that the Pt/CaO-600 catalyst exhibited excellent catalytic activity towards furfuryl alcohol hydrogenation. Gratifyingly, the furfuryl alcohol conversion achieved 99.8%, and the yields of 1,2-pentanediol and 1,5-pentanediol were 48.6% and 21.5% respectively at 210℃ under 4MPa H2. The good activity of Pt/CaO could be attributed to the fact that the carrier CaO provided appropriate amounts of basic sites, which facilitated the ring-opening reaction of furfuryl alcohol, thus improving the conversion and pentanediol selectivity. Moreover, the as-prepared Pt/CaO also exhibited excellent performance in recycling experiments, wherein the yields of 1,2-pentanediol and 1,5-pentanediol reached 40.3% and 17.0% respectively with 96.5% furfuryl alcohol conversion after being repeated four times.

    Selective hydrogenation of methyl 3-hydroxypropionate over zirconium-modified Cu/SiO2 catalysts
    LI Weijie, KANG Jincan, ZHANG Chuanming, LIN Lina, LI Changxin, ZHU Hongping
    2024, 43(3):  1328-1341.  doi:10.16085/j.issn.1000-6613.2023-0477
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    A series of the zirconium (Zr)-modified Cu/SiO2 catalysts were synthesized by ammonia-evaporation method and applied in the gas-phase hydrogenation of methyl 3-hydroxypropionate (3-HMP) to 1,3-propanediol (1,3-PDO). N2 adsorption-desorption, XRD, ICP-OES, H2-TPR, NH3-TPD, CO2-TPD, FTIR, TG-DTG, HRTEM, XPS and AES techniques were used for detailed characterizations. Introduction of the Zr species results in a strong interactions between the Cu and Zr species, leading to the generation of more copper phyllosilicate, and thus increasing the specific surface area of the catalyst as well as reducing the particle sizes of the copper species. The addition of Zr also made the copper species better be dispersed over the SiO2 support, increased the Cu+ content and enhanced the electronic absorption of the substrate 3-HMP by the acyl and methoxide groups. Compared with the unmodified Cu/SiO2 catalyst, the Zr-added (0.5%) Cu/SiO2 catalyst showed better catalytic performance. The conversion of 3-HMP as 96.0% was achieved along with the 1,3-PDO selectivity of 84.3%, Resulting in a total yield of 80.9% for 1,3-PDO. These were the best results obtained currently at a high liquid hourly space velocity (LHSV) of 0.10h-1.

    Tuning the catalytic performance of Rh/FePO4 catalyst by reduction temperature for quinoline selective hydrogenation
    LI Kairui, GAO Zhaohua, LIU Tiantian, LI Jing, WEI Haisheng
    2024, 43(3):  1342-1349.  doi:10.16085/j.issn.1000-6613.2023-1394
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    1,2,3,4-tetrahydroquinoline derived from selective hydrogenation of quinoline has vital applications in the fields of pharmaceutical, alkaloid, agrochemical and so on, where tuning the interaction between quinoline molecules and active sites plays an important role in improving the catalytic performance. Herein, the effect of reduction temperature was explored with Rh/FePO4 catalyst employed for the hydrogenation of quinoline. The results showed that the hydrogenation performance decreased along with increasing the reduction temperature, in which the catalyst reduced at 75℃ gave the best performance, yielding 98.5% conversion and >99% selectivity of 1,2,3,4-tetrahydroquinoline, as well as high reaction rate of 353mol/(mol·h). Various characterizations indicated that the catalyst structure changed from FePO4 to amorphous crystal and Fe2P2O7 phase at increased reduction temperature. Meanwhile, the high reduction temperature led to more metallic Rh species and the absent of acidic sites. Combining with the experimental results, we demonstrated that the decline in catalyst performance at high temperature is due to the formation of more metallic Rh species, which strongly coordinated with quinoline molecule and poisoned the active sites. And the catalyst reduced at a low temperature of 50℃ cannot form the metallic Rh species. Comparatively, the catalyst reduced at 75℃ had the suitable electronic property and acidic sites, both of which promoted the hydrogenation of quinoline under mild conditions.

    Materials science and technology
    Design principle and application of self-healing hydrogel
    LIU Mengmeng, QIU Liewei, WAN Zhiwei, LI Shijing, XU Yuyu
    2024, 43(3):  1350-1362.  doi:10.16085/j.issn.1000-6613.2023-0428
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    Self-healing hydrogel is a type of intelligent hydrogels that can repair its structure and function after being damaged by the surroundings. Self-healing hydrogels also have self-healing properties, high safety, fatigue resistance and long service life based on retaining the water absorption and retention properties of traditional hydrogels. In this paper, the self-healing hydrogels in recent years were reviewed, focusing on the combination of physical, chemical crosslinking and multiple action mechanisms, and partial application in wearable electronic products, 3D printing, biomedicine and petrochemical fields. Physical crosslinking included noncovalent interactions such as hydrogen bond, hydrophobic interaction and host guest interaction. Chemical crosslinking included dynamic covalent bonds such as acylhydrazone bond, imine bond and disulfide bond. Multiaction mechanism crosslinking introduced two or more physical and chemical crosslinking simultaneously introduce hydrogel. On the basis of the above research, this review pointed out that the current self-healing hydrogels had many deficiencies, such as complicated preparation methods, single function, inability to respond to multiple stimuli and lack of multi-directional analysis of self-healing mechanisms. Hence, the future research and development of self-healing hydrogels should focus on the research and development of multi-mechanism and multi-functional self-healing hydrogels, explore the mechanism of hydrogel healing process from multiple perspectives and multidisciplinary integration, and accelerate its application in many emerging fields.

    Membrane technologies for monovalent/divalent cation separation
    ZHAO Guoke, ZHANG Yang, LIU Yiqun
    2024, 43(3):  1363-1373.  doi:10.16085/j.issn.1000-6613.2023-0463
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    Efficient separation of monovalent/divalent cations is highly demanded in various industrial processes such as water softening, lithium extraction from salt-lake brine, the production of edible salt and the comprehensive treatment of acidic wastewater. Research on the above membrane materials used in these separation systems has advanced significantly in recent years. This paper presented a comprehensive review of the membrane-based technologies for monovalent/divalent cation separation, including selective cation exchange membranes, nanofiltration membranes, supported liquid membranes and ion imprinting membranes. The optimization strategies and underlying mechanisms for the membrane selectivity were highlighted. The characteristics and applicable scenarios of the above membrane processes were compared. Considering this, it was proposed that the selective ion separation was one of the key areas for membrane separation technology. Clarifying the formation and evolution mechanism of the separation layer at the molecular scale was crucial for improving the controllability of interfacial polymerization reactions. Highly selective ion screening can be realized by controllably constructing recognition sites and mass transfer channels for target ions inside the membrane matrix. Novel membrane materials contained intrinsic and regular pore architectures, such MOFs, COFs, two-dimensional layered membranes, etc., had good development potential for fine ion selection.

    Recent advances in amine-rich membrane for CO2 separation
    XU Zewen, WANG Ming, WANG Qiang, HOU Yingfei
    2024, 43(3):  1374-1386.  doi:10.16085/j.issn.1000-6613.2023-0468
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    Membrane technology for carbon capture is vital to achieve the goal of carbon emission reduction, but limited by the material, the separation performance of membrane materials has upper bound. Amine-based materials can react reversibly with CO2 and dramatically improve the separation performance of membrane materials, and are often introduced into membrane systems as carriers to facilitate mass transfer. In this paper, the mechanism of promoting the mass transfer of CO2 by amine-rich membrane was introduced, and the four types of methods (coating, reaction, grafting and doping) for introducing amine-rich materials into the membrane matrix were summarized. The advantages and disadvantages of the four types of methods were analyzed and the performance of the four types of methods for preparing separation membranes was summarized. This paper showed that the mechanism of amine-based materials for CO2 mass transfer needed to be further explored. It was emphasized that the development of materials with high amino density and the introduction of amino materials into membrane matrix in a more firm way were the future key development directions. The utilization of machine learning to improve the efficiency of membrane material design had guided the development of the field. This work indicated that the performance stability of amine-based membrane materials, equipment stability and process stability under real operating conditions were areas of concern, and that the establishment of a complete amine-based membrane method CO2 capture technology chain still faced huge challenges.

    Preparation and performance optimization of high-nickel cathode materials in lithium-ion batteries
    WU Jianyang, SHEN Lanyao, YU Yongli, WANG Runa, JIANG Ning, YANG Xinhe, QIU Jingyi, ZHOU Henghui
    2024, 43(3):  1387-1394.  doi:10.16085/j.issn.1000-6613.2023-0346
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    High-nickel material has high theoretical capacity, which can be used for promoting the energy density of LIBs. As a type of high-nickel material, LiNi0.8Co0.1Mn0.1O2 has been widely researched. Nevertheless, to pursuit higher energy density, the study on ultra-high-nickel materials (MN>88%) is necessary. Unfortunately, the high content of Ni not only promotes the theoretical capacity, but also causes negative effects on the structure stability of high-nickel materials, which inhibits the practical application of high-nickel materials. Therefore, the preparation technology of ultra-high-nickel materials is significant. Herein, we prepared ultra-high-nickel materials with Ni content of 88%, 90%, 92%, 94%, and 98%, then the relevant physiochemical properties as well as electrochemical performances were investigated. The effects of the increased Ni content on the capacity and the structural stability of high-nickel materials were verified. Furthermore, the ultra-high-nickel material with Ni content of 90% (Ni90) was selected, and the effect of different sintering temperatures was evaluated. It was found that the particle sizes increased as thewith rising temperature, and 750℃ leads led to the best rate and cycling performances of Ni90, in which the particle sizes and the structural stability achieved a balance. Meanwhile, it was revealed that an appropriate sintering temperature was crucial to prepare ultra-high-nickel materials which exhibited both excellent performances and stability.

    Preparation and application of high stability titanium polyester catalyst TiOC@SiO2
    LIU Bin, WANG Yongjun, LYU Wangyang, CHEN Wenxing
    2024, 43(3):  1395-1402.  doi:10.16085/j.issn.1000-6613.2023-0349
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    Titanium-based polyester catalysts are ideal substitutes for traditional antimony-based catalysts due to their high catalytic activity and environmental friendliness. In order to prepare titanium polyester catalyst with hydrolysis resistance, good dispersibility and stable catalytic performance, TiOC@SiO2 catalyst was prepared by reverse microemulsion method. A layer of siloxane was coated on the surface of titanium containing organic compound to stabilize the catalytic activity. The morphology, structure and properties of TiOC@SiO2 were characterized by various modern characterization methods, and its catalytic performance in the synthesis of polyethylene terephthalate (PET) was evaluated. The results showed that the TiOC@SiO2 catalyst had a core-shell spherical structure with a particle size of about 200nm, but no Ti—O—Si bond, and a Ti content of 6.95%. The structure and catalytic activity of TiOC@SiO2 catalyst remained unchanged at 90℃ for 2h. The composite structure significantly improved the hydrolysis resistance of the titanium organic compounds and dispersibility. In the polyethylene terephthalate synthesis experiment, with only 5μg/g TiOC@SiO2 added and polycondensation at 270℃ for 92min, polyester with intrinsic viscosity of 0.677dL/g, terminal carboxyl content of 14.4mol/t and b value of 2.16 was prepared.

    Fabrication of multi-enzyme@ZIF-8 for extraction of anthocyanins from black rice
    WANG Bicong, PAN Dawei, XIE Rui, JU Xiaojie, LIU Zhuang, WANG Wei, CHU Liangyin
    2024, 43(3):  1403-1411.  doi:10.16085/j.issn.1000-6613.2023-0370
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    The α-amylase & cellulase@ZIF-8 (A&C@ZIF-8) nanoparticles with good catalytic activity and thermal stability are fabricated by in situ growth method in bulk solution to couple with solvent extraction process for effective extraction of anthocyanins from black rice. In these nanoparticles, the encapsulated α-amylase and cellulase allow dissociation of plant cell wall via hydrolysis of the α-1,4 glycosidic bond and β-1,4 glycosidic bond. Meanwhile, due to the spatial confinement of ZIF-8 matrix, both enzymes can exhibit good thermal stability and solvent tolerance. The A&C@ZIF-8 nanoparticles show polygonal-spherical shape with average sizes of 405nm, and loading content of 18% for both enzymes. The immobilized α-amylase and cellulase in the A&C@ZIF-8 nanoparticles show good tolerance in environment with temperature higher than 72℃, with their activities respectively 33.2% and 247.3% higher than that of their free enzyme counterparts. By coupling the A&C@ZIF-8 nanoparticles with ethanol-water system for co-extraction of anthocyanins from black rice, the extracted amount of anthocyanins can reach 200.39mg/100g, showing an 26.3% increase as compared to the extraction only with ethanol-water system. This work provides a new strategy for the innovative design and fabrication of enzyme-immobilized functional materials for extraction of actives in plant cells.

    Pilot scale production of porous organic polymers and their application in polyolefin catalysts
    WANG Xiong, KANG Wenqian, REN Yue, QIAO Tongsen, ZHANG Peng, HUANG Anping, LI Guangquan
    2024, 43(3):  1412-1417.  doi:10.16085/j.issn.1000-6613.2023-0437
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    Porous organic polymers (POPs) are widely used in many fields such as adsorption, separation and catalysis. In this research, pilot scale POPs (POP3120T and POP3100) were produced by via of dispersion polymerization, which exhibited excellent flowability and surface morphology. High specific surface area (SSA of 282m2/g), bulk density (0.29g/cm3) of POP3120T with average particle size of 23.4µm (PSD: 1.0) were obtained, which was comparable to inorganic silica gel support. POP3100 obtained higher SSA of 503m2/g with average particle size of 36.0µm (PSD: 0.93). The supported Z-N@POP PP catalysts exhibited good polymerization activity above 1.0×107gPP/(mol Ti·h), high bulk density of 0.36g/cm3 and low fine powder content (≥100 mesh, <1%), which was equal to the level of commercial PP catalysts. Furthermore, the supported Z-N@POP PP catalysts showed high stereoregularity with isotacticity index above 97.5% and broad molecular weight distribution above 11.

    Preparation of polyamide/cellulose acetate thin-film composite forward osmosis membranes and optimization of phase inversion process parameters
    LIN Mingjie, LI Shiyang, MA Junmei, GAO Congjie, XUE Lixin
    2024, 43(3):  1418-1427.  doi:10.16085/j.issn.1000-6613.2023-0441
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    Forward osmosis (FO) technology has the advantages of low operating pressure, energy consumption and membrane fouling. It may contribute to solutions to ease the water and energy shortage in the world. However, the lack of stable and high permselective FO membranes has thwarted its wide spread applications. In this paper, starting from adjusting the process parameters of phase inversion, the structure and properties of cellulose acetate (CA) substrates were effectively controlled by changing the kinds of additives and the operation parameters (coating thickness, solvent evaporation time and coagulation bath temperature). Then polyamide (PA) separation layer was formed on the hydrophilic porous CA substrate by interface polymerization (IP) to obtain the thin-film composite FO membrane. The experimental results showed that when the casting solution composed of 10% CA and Porogen A was cast under a 150μm gap and coagulated at 25℃ to form porous CA substrate, the stable TFC-FO membranes could be prepared from IP to have the best permselectivity. With 1mol/L NaCl solution as the drug substance (DS) and deionized water (DIW) as the feed solution (FS), the FO water flux reached 10.94L/(m2·h) under a low reverse salt flux value of 0.0500mol/(m2·h). Its NaCl rejection rate was 95.0% and the structure parameter (S) was 1404μm.

    Fabrication of aromatic functionalized organosilica membranes and gas separation performance
    QIAN Junming, GUO Meng, REN Xiuxiu, YU Liang, ZHONG Jing, XU Rong
    2024, 43(3):  1428-1435.  doi:10.16085/j.issn.1000-6613.2023-0443
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    Two organosilica presursors, 1,4-bis (triethoxysilyl) benzene (BTESB) with benzene bridges and 4,4'-bis (triethoxysilyl) biphenyl (BTESBPh) with biphenyl bridges were utilized for the fabrication of organosilica membranes via the sol-gel strategy. The two membranes were applied to the gas separation. At 25℃, BTESB membrane displayed a C3H6 permeance of 3.4×10-9mol/(m2·s·Pa)and C3H6/C3H8 selectivity of 9.6. Nevertheless, BTESBPh membrane showed a C3H6 permeance of 1.7×10-8mol/(m2·s·Pa) and a comparable C3H6/C3H8 selectivity of 10.5. BTESBPh membrane networks with biphenyl bridged structures were much looser and could achieve higher gas permeance. The π-π interactions occurred between the big π bond in the benzene ring and the C̿    C bond in the C3H6 molecules, which was beneficial for the preferential adsorption and permeation of the C3H6 molecules. The biphenyl bridges in BTESBPh membranes enhanced the adsorption and permeation process, as evidenced by the increased C3H6/C3H8 selectivity of the BTESBPh membrane under low testing temperatures. This study could provide a reference for the development of high-performance propylene/propane separation membranes.

    Effects of peroxide types on the removal of anti-inflammatory medicines in water with rGO/CNTs catalytic membranes
    YAN Yu, XIA Xin, LUO Junpeng, LIU Dapeng, QIAN Feiyue
    2024, 43(3):  1436-1445.  doi:10.16085/j.issn.1000-6613.2023-0494
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    Sulfapyridine (SSZ) and trimethoprim (TMP) were the typical combinations of anti-inflammatory medicines, and it would cause ecological risks when discharged into water bodies. The carbon mats composited with reduced graphene oxide and carbon nanotubes (rGO/CNTs) were loaded onto the microfiltration membranes, which were used to activate various peroxides for the removal of pollutants. Thus, an in-situ catalytic oxidation system could be built up in the continuous flow mode. Results showed that peroxodisulfate (PDS) and permonosulfate (PMS) were the best alternative for effectively removing SSZ and TMP with rGO/CNTs catalytic membranes, respectively. Meanwhile, the performances of hydrogen peroxide (H2O2)-based systems significantly decreased as increasing continuous operation time. According to the quenching experiments of reactive oxygen species, functional group characterization on the surface of carbon mats and density functional theory calculations, the defects structures in carbon mats were considered as the critical sites for the adsorption and activation of PDS and PMS molecules, resulting in non-radical pathways including surface-confined oxidation and singlet oxygen (1O2). In comparison to H2O2-based systems dominated by hydroxyl radical (·OH) reaction, the PDS and PMS catalytic oxidation processes exhibited more significantly target selectivity, more resistant to background substances in real water matrices and more effectively control membrane fouling. These findings could provide the guides in the further optimizing functional design of carbonaceous catalytic membranes and promoting the development of novel in-situ catalytic oxidation processes.

    Preparation of CeO2-In2O3 heterojunction composites for gas sensing monitoring of triethylamine
    ZHONG Caili, MO Qiulian, SUN Jianhua, DING Ningning, LIAO Dankui, SUN Lixia
    2024, 43(3):  1446-1455.  doi:10.16085/j.issn.1000-6613.2023-0495
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    CeO2-In2O3 composites were synthesized by pyrolysis metal-organic framework method (MOFs) using In(NO3)3∙4.5H2O and Ce(NO3)3∙6H2O as raw materials, terephthalic acid as ligand and N, N-dimethylformamide as organic solvent. The microstructure of the obtained materials was characterized by XRD, TEM, SEM, UV-vis and BET. The gas sensitive properties of obtained CeO2-In2O3 composites were studied. The results indicated that when the molar ratio of In/Ce was 3∶1, CeO2-In2O3 to 1×105μg/L triethylamine (TEA) had the highest response values (48.37), which was 5 times that of pure In2O3 (9.45), response/recovery time was reduced to 36s/22s, and the composite had excellent selectivity and long-term stability at the optimum operating temperature of 173℃. The increased sensing performance can be attributed to the large specific surface area provided by pyrolytic metal-organic skeleton method and the formation of n-n heterojunction.

    Application of graphene composite supported catalyst in the removal of NO from diesel exhaust
    YAN Shoucheng, ZHANG Huihua, XU Qianqian, WANG Yukun
    2024, 43(3):  1456-1465.  doi:10.16085/j.issn.1000-6613.2023-0498
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    Ammonia selective catalytic reduction method (NH3-SCR) is conducive to NO removal from diesel exhaust. In order to suit the conditions and temperature of diesel vehicle tail gas, a NH3-SCR catalyst with graphene and TiO2 composite support was prepared. The following conclusions were obtained through the catalytic activity evaluation of NH3-SCR, XRD, SEM, BET and H2-TPR characterizations. For TiO2 supported catalyst, high content of Ce was beneficial to improve the catalytic activity of NH3-SCR and widen the activity temperature range, while the active component Fe was helpful to its low temperature activity. For the graphene supported catalyst, the active component Ce had better catalytic activity, but Fe was more favorable to high temperature activity. For denitrification catalyst with TiO2 and graphene composite supports, the catalytic activity temperature range was further widened and the powder phenomenon was improved in the catalyst reaction process, but the catalytic activity decreased slightly, among which Fe0.1Ce0.4Ti/10%GR catalyst had the best NH3-SCR activity and NO conversion reached more than 90% in the temperature range of 220—450℃.

    Biochemical and pharmaceutical engineering
    Construction of aminopeptidase on the surface of Bacillus subtilis and its synergic hydrolysis of soybean protein
    YUAN Xiaoli, LI Qingyun, LIU Youyan, LI Jin, BAI Xue, TANG Aixing
    2024, 43(3):  1466-1473.  doi:10.16085/j.issn.1000-6613.2023-0368
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    Aminopeptidase is an important synergistic enzyme for protein deep hydrolysis, however the high cost and poor stability of free enzyme remain the primary limiting factors for their industrial applications. In this study, we constructed a new easily isolated and well tolerated whole-cell biocatalyst which displayed the aminopeptidase derived from Pseudomonas Aeruginosa GF31 on the surface of Bacillus subtilis WB800N spores by surface-display technology. And immunofluorescence analysis indicated that the aminopeptidase was correctly expressed on the surface of spores. The enzyme activity of surface-displayed aminopeptidase reached 75.61U/g at 60℃ and pH=9.0. The aminopeptidase and alkaline protease were used in a synergistic hydrolysis of soybean protein, in which 5.0% of soybean protein was hydrolyzed for 8h at 60℃ with an enzyme ratio of 2∶1 between the alkaline protease and the aminopeptidase, with an initial hydrolysis pH of 10.0 followed by 9.0. The maximum hydrolysis degree was 55.50%, which was 3.3-fold and 1.5-fold times higher than that achieved by surface-displayed aminopeptidase or alkaline protease alone, respectively. Simultaneously, the content of 16 kinds of free amino acids was significantly increased. Specifically, the content of hydrophobic amino acids including leucine, tyrosine, and phenylalanine increased by 19.21mg/L,8.59mg/L and 16.77mg/L, respectively. While the content of umami amino acid including glutamic acid and aspartic acid increased by 13.98mg/L and 4.11mg/L, respectively. These results suggested that aminopeptidase in deep hydrolysis could significantly reduce the bitterness of protein hydrolysate and enhance its umami favor, and had excellent potential for practical use.

    Controllable preparation and properties of photothermal-responsive controlled-release microspheres
    YANG Jiaqi, JU Xiaojie, XIE Rui, WANG Wei, LIU Zhuang, PAN Dawei, CHU Liangyin
    2024, 43(3):  1474-1483.  doi:10.16085/j.issn.1000-6613.2023-0374
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    Single photothermal therapy (PTT) has limited effects and often cannot cure tumors completely. With the integration of material science and biomedicine, multifunctional drug carrier materials have been well developed and utilized, which is conducive to the combined use of PTT with other therapeutic methods, providing an effective strategy for synergistically enhancing antitumor efficacy. In this study, a novel kind of photothermal responsive controlled-release microspheres (PLGA-ICG@PVA/SA) was controllably fabricated by microfluidic technology using poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with indocyanine green (ICG) as the photothermal agent and poly(vinyl alcohol) (PVA)/sodium alginate (SA) as the carrier substrate. The morphology and size controllability, photothermal conversion performance, mechanical properties and biocompatibility of microspheres were systematically investigated. Taking doxorubicin hydrochloride (DOX) as a model drug, the loading capacity and photothermal responsive controlled-release capacity of the microspheres were studied. The results showed that the prepared PLGA-ICG@PVA/SA microspheres had good monodispersity and excellent photothermal conversion effect. The temperature increment was 18.5℃ under 0.5W/cm2 NIR light irradiation for 15min, and the stability was good. The microspheres also had good compressibility and elasticity with a young's modulus of 317.0kPa. In the simulated physiological environment, the release behavior of DOX drug from microspheres conformed to the first-order release kinetic model and exhibited an obvious photothermal response. This microsphere material had broad application prospects in the fields of drug controlled-release and photothermal/chemotherapeutic combination therapy of tumors.

    Fine chemicals
    Thermodynamic properties of four alkyl imidazolium phosphate ionic liquids
    LIU Zepeng, ZENG Jijun, TANG Xiaobo, ZHAO Bo, HAN Sheng, LIAO Yuanhao, ZHANG Wei
    2024, 43(3):  1484-1491.  doi:10.16085/j.issn.1000-6613.2023-1722
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    The density, viscosity, and conductivity of 1-ethyl-3-methylimidazolium dihydrogen-phosphate ([EMIM][DHP]), 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM][DMP]), 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]) and 1-butyl-3-methylimidazolium dibutyl-phosphate ([BMIM][DBP]) ionic liquids were measured in the temperature range of 293.15K to 353.15K under ambient conditions. Some important volumetric properties, including the isobaric thermal expansion coefficients, molecular volume, standard entropy and lattice potential energy were calculated from the experimental density values. The thermal gravimetric analysis was performed in the temperature range of 35℃ to 700℃, resulting in thermal decomposition temperatures up to 271.9—278.6℃. The Walden rule analysis demonstrated that four phosphate ionic liquids complied with the Walden rule well, while [EMIM][DMP] and [EMIM][DEP] were classified as “good ionic liquids”.

    Resources and environmental engineering
    Review on key parameters and storage capacity potential assessment for in-situ carbon mineralization site
    TIONG Michelle, YE Hang, BAO Qi, LIU Qi, JING Tieya, YUAN Haowei, ZHAO Wentao, WANG Xiaolong, XIAN Chenggang
    2024, 43(3):  1492-1505.  doi:10.16085/j.issn.1000-6613.2023-0355
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    The significant greenhouse gases emission, especially CO2 is the main cause of global warming. According to IEA report, carbon capture, utilization and sequestration (CCUS) is proposed as an effective mitigation strategy which accounts for about 15% of cumulative carbon emission reduction. The in-situ mineralization sequestration technology is based on the rapid CO2 mineralization mechanism, utilizing the formations of mafic rocks and ultramafic rocks (such as basalt and peridotite) as carbon storage sites. The mineralization reaction between CO2 and calcium- and magnesium-rich minerals is used to transform them into stable carbonates, achieving permanent and efficient CO2 sequestration. Pilot projects in Iceland and the United States have demonstrated the feasibility of this technology, but no demonstration project has been carried out in China yet. This review presents the mechanism of in-situ carbon mineralization, calculation methods for CO2 storage capacity, and current technical challenges. In addition, the conducted case studies, including their technical details are discussed, while the key parameters required for implementing this technology (include source-sink distance, mineral types, injectivity, and confinement, etc) are provided. Based on the recent research, the future prospects are made, aiming to enhance China’s understanding and attention to the in-situ carbon mineralization technology, at the same time, serving as a guideline for future implementation in China.

    Research progress of polyethyleneimine crosslinked polymer gel system in water-drive reservoirs
    WANG Kai, LUO Mingliang, LI Mingzhong, HUANG Feifei, PU Chunsheng, PU Jingyang, FAN Qiao
    2024, 43(3):  1506-1523.  doi:10.16085/j.issn.1000-6613.2023-0376
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    Polyethyleneimine (PEI) is an environment-friendly and low toxic material. PEI and polymer crosslinked gel system has the advantages of controllable gelation time, high strength of mature gel, high-temperature resistance, long-time stability, and almost unaffected by minerals of reservoir. This paper reviewed the research of various polymer gel systems with PEI as crosslinker. The crosslinking mechanism and the characteristics of those gel systems were clarified. The influence of various factors on the gel system was analyzed. And, the methods to improve the gel performance and successful filed trial were listed, the methods to improve the crosslinking activity of gel system were emphatically analyzed. Finally, it was pointed out that polyacrylamide(PAM)/PEI gel system, as an environment-friendly system, had great application prospects in conformance control and water shutoff of medium and low temperature reservoirs, and it was suggested that the method and the corresponding mechanism of improving the crosslinking efficiency of PAM/PEI system should be studied more extensively and deeply to reduce the loading amount of polymer and crosslinker, and provided a theoretical basis and experimental basis for the promotion and application of this system.

    Review on recycling of graphite anode from spent lithium-ion batteries
    CHU Zhenpu, CHEN Yumeng, LI Junguo, SUN Qingxuan, LIU Ke
    2024, 43(3):  1524-1534.  doi:10.16085/j.issn.1000-6613.2023-0419
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    Lithium-ion battery capacity will reduce to a certain extent after used for 6—8 years and a large amount of waste are generated. The graphite anode accounts for 12%—21% of battery and its recycling is beneficial to the environment protection and economic development. In this paper, the regenerating methods of spent graphite anode into battery-grade graphite are summarized, which include the combination of leaching and calcination, graphite surface coating, preparation of composite materials and heteroatom doping. A brief comparison of these methods is also presented in terms of energy consumption and electrochemical performance. At present, direct regeneration for lithium-ion batteries is considered as the most suitable method for the regeneration of anode materials. In the future, more efficient and eco-friendly leaching agents and the multi-path low-temperature calcination methods should be investigated. In addition, high-capacity anode materials should be studied to composite with spent graphite, as well as the development of low-cost coating on the surface of graphite. Furthermore, the doping mechanism of heteroatoms in graphite is a direction worthy of research.

    Modeling of porous carbon materials based on molecular simulation: State-of-the art
    ZHOU Yihuan, XIE Qiang, ZHOU Hongyang, LIANG Dingcheng, LIU Jinchang
    2024, 43(3):  1535-1551.  doi:10.16085/j.issn.1000-6613.2023-0485
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    Modelling of porous carbon materials serves as prerequisite and foundation for the characterization, structure-performance relationship investigation and adsorption simulation study. In this article, a critical literature survey was conducted on the strategy, application and merits/demerits of approaches to modelling of porous carbon materials based on molecular simulation, and the applicability of various modelling methods was analyzed in demand oriented for screening activated carbon for the purification of volatile organic compounds (VOCs). The results showed that early models constructed by either fragment, basic structural units (BSUs) or basic buildings elements (BBEs) can exhibit some apparent properties of porous carbon materials. Meanwhile, they were incapable of providing guidance for the elucidation of adsorption performance and mechanism of porous carbons. Various modelling methods of porous carbon material can be classified into two groups according to their construction strategy, the mimetic and the reconstructive. The former was suitable for studying the microstructure evolution, but had disadvantages in requirement of high computing power. The latter constructed models via "reconstructing" porous carbon materials by fitting experimental and characterizing data under certain constraint conditions. Among the reconstructive methods, modelling by random packing that can intentionally regulate the pore structure and decorate functional groups of the model, was a promising approach to screening suitable activated carbon matching for purification of specific VOCs even to setting targeted goals for directional preparation of activated carbon. Reasonably, structural model with regulable pore structure and surface chemistry of porous carbons was helpful in adsorption simulation for structure-performance relationships studies. However, it was obvious that the reconstructive modelling methods (including by random packing) can provide guidance for the practical applications of porous carbon materials only till the time, when the pore structure and surface functional groups of porous carbon models could be quantitatively regulated, as well as multi-scale models capable of conducting multi-parameter structure-performance relationship studies would have been developed.

    Study on the preparation of composite adsorbent with titanium-containing blast furnace slag and chromium adsorption performance
    DONG Xiaohan, TIAN Yue, SU Yi
    2024, 43(3):  1552-1564.  doi:10.16085/j.issn.1000-6613.2023-0343
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    Cr(Ⅵ) is a harmful pollutant that not only pollutes the water environment but also causes harm to humans. In this paper, a new composite adsorbent (GLZ-jcz/CS) was prepared for the removal of Cr(Ⅵ) from wastewater, using industrial solid waste containing titanium blast furnace slag as raw material, and the leached slag matrix was obtained by acid leaching and modified by chitosan. The effects of adsorption temperature, pH of wastewater, adsorbent dosage, initial concentration of Cr(Ⅵ) and adsorption time on the adsorption performance of Cr(Ⅵ) were studied. The optimal experimental conditions were determined using the Cr(Ⅵ) adsorption rate as the evaluation index, and the regeneration performance of GLZ-jcz/CS composite adsorbent was investigated. The GLZ-jcz/CS composite adsorbent was characterized by SEM, FTIR, XPS and BET, combined with adsorption kinetic model and adsorption isotherm model analysis to determine the adsorption mechanism. The experimental results showed that the adsorption rate reached 99.8% and the adsorption capacity could reach 67mg/g when the adsorption temperature was 70℃, the pH of wastewater was 4, the amount of adsorbent was 0.13g, the initial concentration of Cr(Ⅵ) was 50mg/L and the adsorption time was 2h. The GLZ-jcz/CS composite adsorbent can still reach over 96% adsorption after six elutions, and the adsorption model was compounded with the proposed secondary kinetic model and the Langmuir adsorption isotherm model.

    Performance and mechanism of the degradation of benzohydroxamic acid by DBD plasma-coupled BiOI catalytic materials
    DONG Bingyan, LI Zhendong, WANG Peixiang, TU Wenjuan, TAN Yanwen, ZHANG Qin
    2024, 43(3):  1565-1575.  doi:10.16085/j.issn.1000-6613.2023-0367
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    A dielectric barrier discharge (DBD) plasma catalytic system was established at ambient temperature and pressure to investigate the effect of discharge parameters on the degradation of benzohydroxamic acid (BHA) by plasma. The catalysts prepared by hydrothermal synthesis were characterized, and the changes in total organic carbon (TOC), pH, and ∙OH radicals during the degradation were analyzed. LC-MS was used to determine the intermediates of the degradation reaction to investigate the reaction’s mechanism. Characteristics of the synthesized BiOI included a high specific surface area, a high pore volume, and high-purity mesoporous nanosheet microspheres. In addition, the DBD could change the crystalline shape and structure of the catalyst, rendering it better catalytic performance. The degradation performance results showed that peak voltage and the volume of blast gas had a significant influence on the degradation rate of BHA. The best result was achieved by adding 0.3g of BiOI catalyst to couple with DBD plasma at a BHA concentration of 80mg/L, a volume of 1000mL, a peak voltage of 24kV, a frequency of 7500Hz, and a blast volume of 30L/min. This increased the degradation rate of BHA from 78.8% to 88.2% compared to the DBD system alone. The degradation mechanism analysis showed that ∙OH was the main active reactant for BHA degradation. Under plasma catalysis, BHA is oxidized and opened to intermediates such as benzoic acid and 2-hydroxyacetic acid, leading to the generation of H2O and CO32-.

    Extraction and separation of carbon from coal water slurry gasification coarse slag by waterflow classifier
    GAO Zenglin, ZHANG Qian, GAO Chenming, YANG Kai, GAO Zhihua, HUANG Wei
    2024, 43(3):  1576-1583.  doi:10.16085/j.issn.1000-6613.2023-0407
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    Extraction and separation of carbon from coal gasification slag is the key to realize its reduction, harmless and resource utilization. This paper takes Yulin gasification coarse slag as raw material and uses the self-developed waterflow classifier, to study the carbon extraction and separation from coarse slag combined with direct waterflow classification and first wet screening and then waterflow classifier. The results showed that the waterflow classifier can effectively achieve the separation of carbon and ash in the coarse slag. By adjusting the water flow velocity and impeller speed, the highest loss on ignition of the floating slag can reach 43.16%, and the loss on ignition of the tail slag can be as low as 6.63%. The combination of wet screening and waterflow classifier can further improve the recovery of carbon in coarse slag, especially for 0.5—0.18mm medium-size samples, the loss on ignition can be increased to 70.05%, this method was significantly higher than the direct waterflow classifier combustible recovery and comprehensive efficiency. The microstructure analysis of products obtained from coarse slag and waterflow classifier showed that the residual carbon particles were mostly irregular in shape, with rough surface and developed pores, while the ash particles were mainly molten spheres of different sizes and irregular smooth and dense particles. The density measurements showed that the higher the residual carbon content of the product, the lower its density.

    Preparation of wood-based cellulose/graphene separation membrane and pollutant separation performance
    CHEN Linlin, YU Fei, Ma JIE
    2024, 43(3):  1584-1592.  doi:10.16085/j.issn.1000-6613.2023-0429
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    The cellulose film was produced by using acidic sodium chlorite and sodium hydroxide solution to remove lignin and hemicellulose from balsa wood. The performance studies on microstructure, element distribution and composition, and wettability of this film were carried out, and the results showed that the adsorption capacity of the cellulose adsorbent after chemical stripping could reach 120.0mg/g for the dye methylene blue, which was in good agreement with both Langmuir and Temkin models. With the shrinkage of membrane pore size and the loading of graphene oxide (GO), the retention performance of the cellulose membrane for antibiotics was greatly enhanced. The pure water flux of the cellulose/GO membrane was increased to 13.5 times of the original flux [from 56.5L/(m2·h) to 764.1L/(m2·h)] at 0.3MPa flux pressure. The retention rate of ciprofloxacin by the cellulose/GO membrane was up to 65.6% (50.9% for ciprofloxacin by cellulose membrane). The related research work provided a new idea for the preparation and application of polysaccharide membranes.

    Construction of a coupled process integrating dissimilatory nitrate reduction and anaerobic ammonia oxidation/denitrification for wastewater treatment
    ZHAO Ruiqiang, ZHOU Xin, NIU Bingxin
    2024, 43(3):  1593-1605.  doi:10.16085/j.issn.1000-6613.2023-0449
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    An anaerobic expanded granular sludge bed reactor (EGSB) was used to treat simulated wastewater containing COD, ammonia and nitrate nitrogen to rapidly establish anaerobic ammonium oxidation (Anammox) process in a high-concentration organic wastewater treatment system. By inoculating a small amount of Anammox sludge and gradually increasing the concentration of ammonia nitrogen, the system successfully started the Anammox reaction after 58d of continuous operation, at which the total nitrogen and COD removal efficiencies were stable to over 97% and 98%, respectively. Mass balance showed that the contribution of Anammox reaction pathway to nitrogen removal gradually increased, and dissimilatory nitrate reduction (DNRA) coupled with Anammox and denitrification together contributed to simultaneous nitrogen and carbon removal in the system. Microbial community analysis found that the relative abundance of Candidatus Kuenenia rapidly increased from 0.27% to 35.87%, and DNRA bacteria (Ignavibacterium, Thermogutta) and denitrification bacteria (Azospira, Gp3) co-existed in the system. The key functional genes of Anammox, DNRA, nitrate reduction and nitrite reduction were detected by gene annotation method. During the operation, the granular sludge turned reddish in color and its particle size increased. Extracellular polymeric substance (EPS) analysis showed an increase in polysaccharide (PS) and protein (PN) contents and a decrease in PN/PS. Three-dimensional fluorescence spectroscopy revealed an increase in humic acid-like substances. These results of the study provide a novel process pathway for efficient treatment of high concentration organic nitrogenous wastewater.

    Transformation of trace metals Cu and Pb during high temperature flue gas pyrolysis of waste tires
    ZHANG Xin, TANG Jiyun, CHEN Juan, SONG Zhanlong, DONG Yong, YAO Hong
    2024, 43(3):  1606-1613.  doi:10.16085/j.issn.1000-6613.2023-0450
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    Waste tires (WT), as a common solid waste, can cause great pollution to the environment if it is disposed unreasonably. In this paper, coal-fired high-temperature flue gas for pyrolysis of WT was used, focusing on the release characteristics of heavy metals Cu and Pb during the pyrolysis process, and the control effects of different metal oxides (CaO, MgO, Al2O3, Fe2O3) on two heavy metals. In addition, the effect of adding PVC on the migration release of two heavy metals was also investigated. The results showed that when the pyrolysis time was 10min, the two elements had been basically released completely. The enrichment of Cu was promoted at high temperature, while the release of Cu was promoted at low temperature. Metal oxides had a controlling role in the release of two elements. MgO promoted the enrichment of Cu, while Al2O3 promoted the enrichment of Pb. When WT with added polyvinyl chloride (PVC) was pyrolyzed, the enrichment of Cu was promoted at low temperature while the release of Cu was promoted at high temperature. However, regardless of the temperature, the addition of PVC resulted in almost complete release of Pb. Furthermore, Fe2O3 inhibited the release of both heavy metals.

    Migration and transformation characteristics of heavy metals during incineration of oily sludge
    GONG Zhiqiang, LIU Lei, WANG Shaohua, HAN Yue, GUO Junshan, SHANG Panfeng, ZHU Lingkai, ZHENG Wei
    2024, 43(3):  1614-1620.  doi:10.16085/j.issn.1000-6613.2023-0453
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    In order to clarify the influence of mineral compounds on the migration and transformation of heavy metals during the incineration of oily sludge, this paper took the oily sludge from the tank bottom of Shengli Oilfield as the research object, and conducted incineration experiments with the addition of CaO, Fe2O3, Al2O3, and MgO using a horizontal tube furnace. The total amount, leaching characteristics and risk analysis of heavy metals in the obtained incineration bottom ash were carried out respectively. The results showed that minerals indicated good adsorption effect on heavy metals during incineration, and CaO exhibited the best adsorption effect on Cu, Cr, Pb and As with a residual rate of 93.40% for Cu. Different mineral compounds were found different inhibition effects on heavy metal leaching. In general, Al2O3 had the strongest inhibition effect on the leaching characteristics of Cr, Zn, Pb, As and Cd with leaching rates of Zn, Pb, and As all below 5%. The impact of minerals on the risk of heavy metals was no strong regularity. CaO and Al2O3 had a significant effect on reducing the risk of Zn and As with the bioavailable content of Zn and As both below 18%.

    Phase equilibrium of Na2SO4-NH3-CO2-H2O system in preparation of sodium bicarbonate from sodium sulfate
    HU Hongyuan, ZHANG Yang, ZHANG Hedong, FAN Bingqiang, ZHENG Shili, TANG Jihai
    2024, 43(3):  1621-1629.  doi:10.16085/j.issn.1000-6613.2023-0472
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    It is of great significance to master the phase equilibrium law of Na2SO4-NH3-CO2-H2O system to optimize the process of preparing sodium bicarbonate with high utilization of sodium sulfate. In this paper, the liquid-solid equilibrium relationship of Na2SO4-NH3-CO2-H2O system and its sub-system Na2SO4-NH3-H2O was studied by isothermal solution equilibrium method at 303.15K, 323.15K and 343.15K at 101.3—1099.0kPa. The equilibrium law of SO42-, CO32- and HCO3- in the Na2SO4-NH3-CO2-H2O system and the Na2SO4-NH3-CO2-H2O system were obtained. The results showed that ammonia in the Na2SO4-NH3-H2O system had a strong salt-out effect on sodium sulfate. Under the action of ammonia, the equilibrium solid phase of the system existed in the form of anhydrous sodium sulfate when the temperature was lower than 305.55K. At the same time, the solution of sodium sulfate ammonia salt water could promote the dissolution of sodium sulfate by carbonation of carbon dioxide. Low temperature and high pressure could promote the carbonation of sodium sulfate ammonia brine solution and improve the conversion of sodium sulfate to sodium bicarbonate.

    Heavy metal leaching toxicity of typical grate furnace/fluidized bed furnace waste incineration fly ash and their chelated products
    ZHENG Yu, LI Jingjie, ZHANG Yufeng, ZHAO Mengqi, ZHANG Na, ZHOU Ao, YU Wei, TAN Houzhang, WANG Xuebin
    2024, 43(3):  1630-1636.  doi:10.16085/j.issn.1000-6613.2023-0502
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    Fly ash from waste incineration is rich in heavy metals, dioxins and other pollutants, which is a hazardous waste and needs to be treated in an environmentally sound manner. At present, the solidification/stabilization + landfill method is widely used in domestic waste incineration plants to dispose of fly ash. In this paper, we sampled the domestic grate furnace waste fly ash and fluidized bed fly ash, and their chelated products. We compared and analyzed the characteristics of two types of fly ash, the leaching characteristics of heavy metals before and after chelation, and analyzed the effects of the differences between fly ash before and after chelation on the stabilization of heavy metals using XRD, XRF, and SEM methods. It was found that chelation can bring the heavy metal problem of fluidized bed fly ash under control and the leaching concentrations of Cd in the fly ash of grate furnace after chelation were still exceeded, pointing out the shortcomings of the current solidification/stabilization method for fly ash treatment. This method can make the fly ash surface dense by cement wrapping, which can reduce the leaching of heavy metals to a certain extent, but the effect of stabilizing heavy metals with chemicals was not obvious. Therefore it was not easy to achieve long-term stabilization of heavy metals and had no sustainable development potential. This paper can provide a reference for further research on new waste incineration fly ash disposal technologies in a targeted manner.

    Reaction dynamics and influencing factors of capacitive deionization desalination using γ-Al2O3 / CuO-ACF
    CHAI Duosheng, GAO Feng, WU Youbing, SUN Xin, HAO Ran, YANG Yu, JIAO Xiangfei
    2024, 43(3):  1637-1647.  doi:10.16085/j.issn.1000-6613.2023-1600
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    Developing electrode materials with a high desalination rate and long life is one of the research hotspots in the field of capacitive deionization (CDI) water treatment technology. CDI electrode (γ-Al2O3/ CuO-ACF) was successfully produced by combining laminated CuAl-mixed metal oxide with activated carbon fibers with a one-pot hydrothermal method. The surface morphology, structure and electrode properties of the samples were characterized by SEM, XRD, FTIR and CV. When the voltage increased from 0.8V to 1.6V under NaCl concentration of 500mg/L, the specific electroabsorption capacity, desalination efficiency, current efficiency and energy consumption increased for both electrodes, while those four parameters for γ-Al2O3/ CuO-ACF were 23.4%—55.3% higher, 44.8%—82.0% higher, 65.5%—90.0% higher and 15.0%—21.4% lower than those for ACF. Under NaCl concentration of 500mg/L and humic acid concentrations of 5—10mg/L, desalination efficiency for ACF was decreased, but that for γ-Al2O3/CuO-ACF was only decreased at humic acid concentration of 10 mg/L. After 15 desalination cycles, the retention rate of desalination efficiency was 96% for NaCl solution system, but that was decreased to 92% with the addition of humic acid. The ion adsorption processes for both cases followed the Langmuir isotherm adsorption kinetic equation, indicating that the salt ions were physically adsorbed on the electrode surface as a single molecular layer. Compared with conventional ACF electrodes, the γ-Al2O3/CuO-ACF electrode had excellent recoverability, stability and enhanced electrochemical properties.

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