The petroleum and chemical industry is a “three high” industry with high energy consumption, high pollution and high carbon emissions. Under the goals of carbon peak and carbon neutrality, it is an urgent need to promote the coordinated and sustainable development of the petroleum and chemical industries and the ecological environment. In this article, the measures and actions taken by typical countries and their petroleum and chemical industries are summarized to face the carbon peak and carbon neutrality goals from national and corporate levels. The energy consumption and carbon dioxide emissions of petroleum and chemical products in different production routes are compared such as ethylene and refined oil. The characteristics of China’s regional energy distribution, the output value of the petroleum and chemical industries and the carbon dioxide emissions of each province are also analyzed. The petroleum and chemical industries, therefore, may be included in the national carbon market during the “14th Five-Year Plan” period as a major carbon emitter. China’s petroleum and chemical industry should build a clean, low-carbon, energy-saving and efficient technological process system to promote the high-quality development by learning from the advanced carbon emission reduction experience of developed countries, basing on its own national conditions, comprehensively considering the country’s energy distribution and the energy consumption and carbon dioxide emissions of the production of petroleum and chemical products. The core task of carbon dioxide emission reduction in the petroleum and chemical industry is to build green integrated chemical parks by adjusting the regional energy structure and optimizing technological processes, supplemented by the comprehensive utilization of renewable energy such as wind and solar energy, and by the use of carbon capture, utilization and storage technologies for carbon fixation. In addition, as the reduction of other greenhouse gases such as methane has been put on the agenda, technical research also needs to be accelerated.

In distillation system, separation of high boiling point and heat sensitive material system has problems of high heating temperature and long heating time, which is easy causing the deterioration of heat-sensitive material, and it has been the difficulty of efficient separation and purification. In this paper, the principle of distillation separation of high boiling heat and heat sensitive material system is summarized, and the process requirements of low operating pressure and short residence time is proposed. The advantages, disadvantages and applications of molecular distillation and vacuum distillation (including vacuum distillation, vacuum fractionation and vacuum batch distillation) in the separation of high boiling point and heat sensitive systems are summarized. It is found that the vacuum degree and separation degree of molecular distillation are higher than vacuum distillation, but the separation efficiency and industrialization degree of molecular distillation are lower than vacuum distillation. Finally, for the separation of high boiling point and heat sensitive systems by distillation, it is still necessary to explore new processes and new equipment to improve separation efficiency and reduce separation energy consumption, so as to facilitate industrial-scale applications.

The loop heat pipe, abbreviated as the LHP, is an enhanced heat transfer element using phase change of working fluid for heat transfer. It is widely used in the waste heat recovery, the solar collectors and heat dissipation of the electronic devices. The performance of the capillary wick in the LHP evaporator is always focused. The 3D printing wick overcomes the limitations of uneven pore size distribution and high randomness of the sintered wick. Based on the characteristics of the gas-liquid two-phase flow in the LHP evaporator, the upper layer of the wick as the liquid-absorbing layer and the lower layer as the evaporating layer were defined. It was found that when the pore diameters of the evaporation layer are constant, increasing the pore size of the liquid absorbing layer will reduce the superheat in the evaporation zone; reducing the pore size of the liquid absorbing layer will cause dry burning in the evaporation zone, both of them will limit the heat transfer performance of the LHP. In addition, while the pore diameters of the absorbing layer are constant, increasing the pore size of the liquid-absorbing layer will cause heat leakage; reducing the pore size of the evaporating layer can strengthen the heat transfer performance of LHP. The composite capillary wick with a pore size of 100μm for the evaporation layer and 200μm for the absorbing layer has the highest heat transfer coefficient and the highest heat capacity.

Heat transfer enhancement and effects of graphene oxide (GO) nanofluid on a pulsating heat pipe (PHP) were studied experimentally. Results showed that heat transfer performance of the GO/water PHP was significantly affected by the filling ratio, concentration and heating power. At a lower filling ratio, e.g. 30%, the PHP worked under the combination of two-phase thermosyphon and pulsation role, showing the advantage of lower thermal resistance but the shortage of easier dry-out. Adding GO nanoparticles could improve the heat transfer performance, such as reducing the thermal resistance and alleviating dry-out effectively. Especially in the mass fraction of 0.05%—0.08% and Q=10—50W, the thermal resistance of the GO/water PHP was lower about 38.1%—74.1% than that of the water PHP. In the mass fraction of 0.08%—0.1%, the dry-out limitation Q_max was higher about 33% than that of pure water. At a higher filling ratio, e.g. 80%, the PHP had smaller vapor phase space for the fluid to move or pulsate. Thus, its overall operation was not quite satisfactory compared with the lower and medium filling ratios. At a higher filling ratio (FR=80%), adding GO nanoparticles could not improve the heat transfer performance of the PHP apparently, and the heat transfer performance was even deteriorated at higher concentrations (the mass fraction of 0.1%). In terms of the thermal resistance and dry-out limitation, the PHP achieved the best overall performance at a medium liquid filling ratio (FR=50%), and especially in the mass fraction of 0.03%—0.08% and Q=20—105 W, thermal resistance reduced about 18.9%—54.4% compared with the water PHP, showing the obvious enhancement effect. Finally, an empirical correlation was fitted based on Kutateladze number (Ku), Bond number (Bo), Morton number (Mo), Prandtl number of liquid (Pr), and Jacob number, to predict the thermal performance of the GO/water PHP with the nanofluid mass fraction in the range of 0—0.1% and the filling ratio in the range of 30%—80%.

In the nucleate boiling zone of the spray cooling, the impact of the droplets with the liquid film and the bubbles in the liquid film has an important effect on the process heat transfer. A two-dimensional numerical model of a droplet impacting liquid film with bubbles was established. The model using water as the cooling fluid was used to simulate the impact process and heat transfer laws. The results showed that when the We was 6.94 and the quantity of dimension one liquid film thickness was 0.5(corresponding droplet velocity 0.5m/s, liquid film thickness 1mm), the liquid film was not disturbed significantly, and the motion shape was similar to ripples. When the We increased to 111.11(corresponding droplet velocity 2m/s), the gauge pressure at the junction of the droplet and the liquid film reached 6000Pa, which became the driving force of the neck jet phenomenon and gradually developed into a crown splash. The existence of bubbles hindered contact between the droplet and the heating surface, but as the bubbles burst, the droplet directly contact the heating surface, which made the surface heat transfer coefficient near the impact point much larger than other areas. The peak value of the surface heat transfer coefficient increased with the decrease of the liquid film thickness, or with the increase of the droplet velocity. The research results can provide a basis for further research on spray cooling system.

In order to achieve a safe, continuous and stable supply of biomass feedstock to the fluidized bed pyrolysis reactor, a cold test apparatus for fluidized bed pneumatic feeding was designed and constructed. Larch and quartz sand were used as raw material and bed material respectively. The minimum fluidization velocity of the apparatus was measured and the effects of fluidized gas velocity, injection gas velocity, flow rate, initial static bed height, bed size and feedstock particle size on the feeding characteristics were studied. Experimental results showed that increasing the fluidized gas velocity and injection gas velocity could increase the feed rate. Fluidized gas provided feed space for biomass particles through fluidization of bed material. Injection gas provided kinetic energy for biomass particles and balanced part of the bed pressure. Increasing the particle size of biomass and bed material was detrimental to the feeding characteristics. Reasonable control of the gas flow ratio could improve the feeding rate and feeding stability. A three-phase flow model of biomass, bed material and gas was constructed to research the relative relationship between different parameters and feed rate. Experiments were carried out to verify the model. Results showed that the derivation error was ±13%.

With the intensification of chemical equipment, parallel towers are often damaged due to large cross-flow vibration. However, the coupling mechanism among parallel towers is complex, which is rarely reported. In order to solve this problem, a rigid truncated model with elastic support was used to simulate the cross-flow vibration of parallel towers, and wind tunnel experiments were carried out to analyze the cross-flow vibration characteristics. The cross-flow displacement of each tower was measured, and the cross-flow vibration characteristics of the parallel towers were analyzed. In addition, a micro fins were designed, and the best vibration reduction effect was achieved by adjusting the size parameters of micro fins. The research showed that the cross-flow vibration characteristics of parallel towers can be divided into three typical regimes according to the range of spacing ratio, which contains "single bluff body" regime, "reattachment" regime and "co-shedding" regime. When spacing ratio S/D<2, the upstream tower will gallop at a smaller reduced velocity, and there will be energy conversion between upstream and downstream towers, which should be avoided in engineering practice. When the thickness parameter of micro fins is greater than 0.1D and the length parameter is greater than 0.9D, the vibration reduction effect of micro fins is the best, which can prevent wake galloping and reduce the cross-flow amplitude of parallel towers by 78.63%—95.67%.

Ethyl levulinate is a potential biomass-based platform compound, which has a wide application in chemical industry. The traditional methods for manufacturing ethyl levulinate are mainly in a batch reactor, which had a low efficiency, difficult in product separation and a long technological process. Therefore, a reactive distillation process in producing ethyl levulinate was proposed. Based on the results of pilot-scale experiments, the reactive distillation technological process was established using Aspen Plus simulation software, the key parameters, such as reflux ratio, feeding position, feed mole ratio and theoretical stage numbers were investigated, and the optimal configuration for the synthesis of ethyl levulinate using conventional reactive distillation technology was obtained. In order to obtain ethyl levulinate with a purity higher than 99.9%, the double column reactive distillation purification process and the reactive dividing-wall distillation process were further proposed, and through the comparison of product purity and energy consumption of these two processes, the effectiveness of reactive dividing-wall distillation process in producing ethyl levulinate was verified and its energy saving effect was demonstrated.

Due to the influence of the gas field and the transportation environment, the field operation has been fluctuating for a long time, and the stable operation of the device is closely related to whether the response action under different working conditions is timely and effective. In order to analyze the response characteristics of the device under different operating conditions, an optimization study was carried out based on the actual operation of the natural gas decarbonization cycle experimental device built in the laboratory, and the key influencing factors were analyzed. The research results showed that in the single-factor experimental study, the influence of different intake air flow, tower internal pressure and lean liquid inlet temperature on the temperature field in the absorption tower and the response characteristics of the flash tank liquid level under start-up conditions had little difference. However, when the starting condition was at a large inlet flow, a high tower pressure, and a low or high lean liquid inlet temperature, the controller response would be delayed to a certain extent or the level fluctuation of the tower kettle was severe. Therefore, taking the response time of the bottom of the absorption tower as the evaluation index, and using the BBD design method to conduct a response surface analysis of the interaction of various factors, it was found that the absorption pressure had a very significant impact on the response time of the bottom of the tower, and the three factors interact with each other. Among them, the interaction between the absorption pressure and the temperature of the lean liquid entering the tower had a more significant impact on the target value.

The heat exchanger of crude oil petrochemical unit is often affected by fouling, which leads to the serious decline of heat exchanger performance and the decline of heat exchanger network performance. At the same time, due to the coupled relationship between heat exchangers, the performance decline of different heat exchangers has different effects on the change of heat exchanger network performance. In the past, cleaning decisions were mainly made based on the performance degradation of a single heat exchanger to a certain extent, resulting in the poor operation of the heat exchanger network. Therefore, a method of heat exchanger network cleaning decision-making based on intelligent prediction and mechanism was proposed in this paper. The intelligent prediction model was established for the operation data of heat exchangers to obtain the performance change trend of heat exchangers. Combined with the performance simulation model of heat exchangers network, the performance change trend of heat exchanger network was further obtained, so as to formulate the cleaning scheme from the perspective of the performance change of heat exchanger network. Based on the operation data of crude oil heat exchangers, the neural network prediction model was established, which has good prediction accuracy. Through the case study of heat exchange network of a crude oil distillation unit, when the performances of HE1, HE2 and HE5 heat exchangers decline at the same time, the annual additional utility energy consumption of heat exchanger network increases by 12.1%. Compared with the traditional cleaning scheme based on the performance of single heat exchanger, the annual additional cost of utility, loss cost and annual total cost of the cleaning scheme based on the performance degradation of heat exchanger network are reduced by 13.1%, 14.1% and 13.8%, respectively, while the cleaning number of times is only increased by 3.

Due to the high dimension of fault diagnosis data in chemical process, the fault features are not easy to distinguish, and the SOM network is easy to fall into the problem of local best. A fault diagnosis method based on KFDA and DE algorithm to optimize SOM neural network was proposed. Firstly, Euclidean distance was used to weight the distance between classes, so as to avoid the problem of overlapping of projected data due to the large distance between classes. As a consequence, the fault data samples could obtain better projection effect and optimize the classification performance. Then, the DE algorithm was used to dynamically adjust the weight vectors of SOM neural network, which effectively avoids the problem of falling into local optimum due to the appearance of "dead neurons". The fault data of TE process and PX disproportionation process were tested. The results showed that compared with traditional SOM network, KFDA-DE-SOM algorithm has higher classification diagnosis accuracy and can be effectively applied to the fault diagnosis of the chemical process.

Coke is easy to be formed during thermal treatment of bio-oil, which is one of the bottleneck problems that hinder the large-scale use of bio-oil. Therefore, the knowledge about the coke formation of bio-oil during its thermal treatment is the foundation for the efficient thermochemical use of bio-oil. In this paper, the current research progress of coke formation from the bio-oil pyrolysis process is reviewed from the angles of key reaction parameters (temperature, heating rate, atmosphere, pressure, ash content), bio-oil chemical composition, interactions among bio-oil organic components, and free radical reaction characteristics. This paper analyzes the influences of the key operating parameters on the coking behaviors of bio-oil during its thermal treatment, and also summarizes the coke formation from the different components of bio-oil and the coking behaviors of bio-oil affected by the interaction among bio-oil components. Furthermore, in view of coke formation mechanism of bio-oil and the physical and chemical properties of coke, the potential utilization of the coke as fuel and carbon material is summarized. Finally, it is pointed out that clarifying the coke formation mechanism of bio-oil required further research from the perspective of the interaction mechanism among bio-oil components and the free radical reactions mechanism. This paper provides a theoretical reference for realizing high-efficiency thermal utilization of bio-oil.

Pyrolysis of low-rank coal is one of important ways for coal clean and efficient conversion. Dust removal of high temperature oil-gas is a bottleneck restricting its industrialization. The hot oil-gas has the properties of high temperature, large dust content, consisting of much polycyclic aromatic hydrocarbon, easy condensing and carbon precipitating. As a result, the dust collector and subsequent process pipeline are easily blocked, which deteriorates the quality of coal tar. This review analyses the application status of the important high-temperature dust removal technologies in relevant fields, including wet dust removal, cyclone dust removal, electrostatic dust removal, ceramic tube dust removal, metal filter dust removal, and granular bed dust removal. The advantages and disadvantages of each technology are summarized, as well as the patent status in the field. The technologies of granular bed dust removal, catalytic dust removal, and combined dust removal are expected to be the future development direction in this field.

At present, CO₂ capture and storage technology is the most effective way to achieve CO₂ emission reduction. Wherein, CO₂ mineral sequestration mainly utilizes the reactions of carbon dioxide with calcium and magnesium silicate minerals to form stable carbonates, and thus can permanently store CO₂. The principles and pathways for CO₂ mineral carbonation are briefly introduced in this paper. Indirect carbonation receives more attentions due to the moderate reaction condition, higher mineralization efficiency and possibility for recovering valuable byproducts. This paper reviews and compares the carbonation process by using natural minerals and industrial solid wastes as feedstock. It is found that the latter is more conducive to the CO₂ mineralization process. This process realizes the disposal of industrial solid wastes while storing CO₂, realizing the treatment of waste with waste, which had certain advantages in economy. Based on above, this paper takes blast furnace slag as representative and summarized its research progress in CO₂ mineral carbonation. It is pointed out that using recyclable reagents and recovering valuable elements from blast furnace slag can improve the economy of CO₂ mineralization. To realize the industrial application of the CO₂ mineralization technology, the scale-up experiments, life cycle assessment and developments of new approaches with low energy consumption should be paid more attentions to.

In order to solve the problem of high COD and difficulty in direct discharge of flowback water from shale gas hydraulic fracturing, three methods including individual ozonation, individual ultrasound, and ozonation-ultrasound combination (O₃+US) were compared. O₃+US had the best performance because it could produce much more radicals than the other two methods. During the O₃+US treatment, firstly, the organic pollutants in flowback water could be oxidized directly to form aldehydes and ketones by O₃, and then oxidative degradation of free radicals happened. At the same time, the color of flowback had the characteristic change corresponding to the process. The effects of pH, US power, catalyst type, catalyst dosage, and reaction time on COD reduction of O₃+US were investigated. The COD reduction increased with decreasing pH and increasing reaction time, and increased firstly and then decreased with increasing US power. The recommended O₃+US condition was as follows: O₃ concentration 42mg/L, pH 2.5, US power 800W, catalyst MnO₂ 0.45g/L, and reaction time 100min. The COD reduction was 68.17% at the recommended condition. In addition, it was found that the degradation kinetics of organic pollutants in flowback water by O₃+US was likely to be second-order kinetics.

The unglazed PV/T system with full photovoltaic coverage has a simple structure and excellent electrical performance, but its thermal efficiency is low and the study on its energy loss is rare. In this paper, based on the first and second laws of thermodynamics, the energy balance equations of unglazed PV/T were established respectively, and an experimental platform was built to carry out the performance test under different temperatures and flow conditions. The cooling effect of working medium was verified by combining the temperature curve of the PV cell, and the thermodynamic characteristics of the system was analyzed from the perspective of enthalpy-entropy-exergy. It was found that the water-cooled channel improves the efficiency of photovoltaic modules and the uniformity of the temperature field, and shortening the water heat collection time contributes to energy saving and revenue. Ambient temperature was an important factor affecting the thermal efficiency, thermal exergy efficiency and heat loss rate of PV/T system, while the electrical efficiency was more obviously affected by the flow rate. Under the test conditions, the maximum electrical, thermal, and comprehensive efficiencies of the unglazed PV/T system were 17.36%, 25.37%, and 70.12%, respectively. The high electrical efficiency ensures the quality of energy collection, and the water collection temperature could be adjusted by the flow to meet the needs of life. Increasing the flow rate could improve the exergy efficiency of the PV/T, and the optimization plan involving the pump can further improve the economy of the system. The increase of system entropy was negatively correlated with the exergic efficiency, and it showed a decreasing trend with the increase of flow rate. The data showed that the exergy efficiency of the PV/T system reached the maximum value of 19.05% when the flow rate was 0.06kg/s, corresponding to a minimum entropy of 0.0191kW·h/K.

Electrocatalytic reduction of CO₂ to alleviate the energy crisis and global warming has become a research hotspot in catalysis. However, due to the close oxidation-reduction potentials of different reaction pathways, the product selectivity of electrocatalytic reduction of CO₂ is not high and should be improved. So far, carbon monoxide (CO) and formic acid (HCOOH) can be obtained with high-selectivity in aqueous electrolytes. The mechanism of electrocatalytic reduction of CO₂ to CO is described in a three-step process of CO₂ adsorption, two-electron transfer and CO desorption. The recent research progress of noble metal catalysts, transition metal complex catalysts and non-metallic carbon-based materials is introduced, including:①the influence of crystal face design, morphology control and surface functionalization of noble metals on the reaction activity and product selectivity; ②the electron transfer paths of iron porphyrin, cobalt phthalocyanine and nickel triazine in the reduction of CO₂ to CO; ③the coupling effect between heteroatoms and carbon matrix in non-metallic carbon-based materials. The advantages and disadvantages of various catalysts are briefly summarized. Among the three kinds of catalysts for electrocatalytic reduction of CO₂ to CO, the non-metallic carbon materials have high CO Faraday efficiency, and they have potential application advantages in the electrocatalytic reduction because of their low cost, simple preparation and controllable structure. Carbon materials will be one of the candidate materials of novel catalysts which could realize commercial application.

Due to their unique carrier structure, excellent chemical stability and adsorption properties, carbon-supported metal materials show broad application prospect in environmental catalysis, and hence are expected to become a new generation of green catalysts. It is paramount to study the correlation between the carbon-supported metal catalyst of different dimensions and the activation mechanism of peroxymonosulfate (PMS) for developing pertinent environmental functional materials. Hence, this review summarizes the advance of PMS activation by multidimensional carbon-supported metal catalysts for the water treatment, including zero-dimensional, one-dimensional, two-dimensional and three-dimensional composites. The impacts of interactions between carbon material and its supporting metal, non-metallic element doping and the activation mechanism of PMS have been deeply explored. Finally, the future development directions of supported environmental catalytic materials, such as single-atom catalysis, multi-reaction center system and photoelectric catalytic system, are analyzed and prospected.

Selective oxidation of light olefins to produce the corresponding aldehydes and other oxygen-containing compounds is a key step in the production of important organic chemical intermediates and products. Molybdenum bismuth composite metal oxides have attracted wide attentions in industry and academia because of their excellent catalytic performance. However, there is still debate on the selective oxidation mechanism on the catalyst and the nature of the catalytic reaction. This work systematically reviews the research progress of using molybdenum bismuth composite metal oxides as catalyst in selective oxidation of light olefins to aldehydes. It is pointed out that the micro-structure and catalytic performance of molybdenum bismuth composite metal oxides are mainly controlled by three strategies including the phase structure of bismuth molybdate, additives and carriers. And the selective oxidation reaction mechanism over the molybdenum bismuth composite metal oxides is discussed and summarized. Finally, the development of molybdenum-bismuth composite metal oxides in selective oxidation reaction is prospected to provide ideas for their modification and the exploration of efficient catalysts for light olefins to oxygen-containing compounds.

On the basis of Al₂O₃, K₂O, CaO promoters, the experimental scheme of 17 samples with univariate, bivariate, trivariate and quadruvariate components was constructed for MgO, V₂O₅, ZrO₂,WO₃ four promoters, and the effect of each variable on the performance of the catalyst was investigated by simple contrast method and characterized by SEM-EDS, H₂-TPR, N₂-TPD, XRD, BET. The results showed that the samples with the highest activity in univariate, bivariate, trivariate and quadruvariate samples contained V₂O₅, ZrO₂ or WO₃ promoters, and the outlet ammonia concentration increased to 19.06%, 24% relative increase, with each additional promoter, indicating that the catalyst activity was related to the superposition and interaction of promoters, in which ZrO₂ and MgO were beneficial to the uniform distribution of elements in the catalyst. It can increase the number of active sites of the catalyst, increase the specific surface area of the catalyst, and improve the heat resistance of the catalyst. V₂O₅ and WO₃ decreased the apparent activation energy of the catalyst, increased the number of active sites of the catalyst, and increased the electron density of α-Fe, while ZrO₂ and MgO were alkaline and V₂O₅ and WO₃ were acidic, and there was acid-base synergism between them. Therefore, the catalyst had the highest activity when MgO、V₂O₅、ZrO₂、WO₃ were added together.

At present, the traditional nitrification method with mixed acids is still often used in the synthesis of α-nitronaphthalene in chemical industry. However, the method has many limitations such as low regional selectivity, poor functional group tolerance, excessive acid waste generated, as well as high cost of post-treatment, which lead to environmental pollution and increase of production cost. This is not in line with the concept of green chemistry. In view of the application prospect of α-nitronaphthalene, a series of supported copper catalysts were designed and synthesized through the steps of impregnation, roasting and reduction, which realized the efficient, economical and green catalytic conversion of naphthalene to α-nitronaphthalene. Among them, the catalyst Cu/ZSM-5 with ZSM-5 as the carrier had the best catalytic performance. The target product α-nitronaphthalene was obtained with high yield (up to 95%) and excellent regioselectivity [(α-∶β-)>(98∶2)]. The catalyst still maintained high catalytic activity and structural stability after recycled for 4 times.

Amorphous mesoporous Al-xP-O catalysts with different P/Al molar ratios (x=1.00, 1.05, 1.10, 1.15, 1.20) were prepared by a one-pot precipitation-evaporation route. The Al-xP-O catalysts were characterized by X-ray diffraction (XRD), N₂ adsorption-desorption method, ICP-AES, NH₃ temperature-programmed desorption (NH₃-TPD) and CO₂-TPD experiment. The relationship between P/Al molar ratio and surface acidic-basic properties of Al-xP-O catalysts were also studied. The results demonstrated that with the increase of the P/Al molar ratio in the range of 1.00~1.10, the amounts of weak acidic sites increased, the amounts of medium-strength basic sites decreased, the conversion to catechol increased, and the selectivity to guaethol increased significantly. As the reaction conditions were: temperature of 270℃, LHSV of 3.0mL/(g_cat·h) and P/Al molar ratio of 1.10, the catalyst exhibited the relative higher catalytic activity. In the reaction period of the 200h stability test, the selectivity to guaethol remained stable at 93.0%, and there was no obvious coke-deposition after reaction. The result indicated the catalyst has good industrial application prospects due to the properties of high stability for the vapor-phase selective synthesis of guaethol with catechol and ethanol.

The ZSM-5 zeolite powders with different silica/alumina ratios(SiO₂/Al₂O₃) were characterized by XRD, SEM, NH₃?TPD and Py-IR. The catalytic performance of the ZSM-5 zeolites was compared in the synthesis of polyoxymethylene dimethyl ethers (PODE) from trioxane and methylal in a batch reactor. The ZSM-5 catalyst with SiO₂/Al₂O₃ molar ratio of 400 showed the highest yield and selectivity of PODE_2-8. Then, the extruded ZSM-5 catalyst were prepared from the ZSM-5 powder (SiO₂/Al₂O₃=400) by adding silica sol and methyl cellulose as binder. The mechanical strength of the extruded ZSM-5 catalyst was influenced by the adding amount of silica sol and the molecular weight of methyl cellulose. The extruded ZSM-5 catalyst were used to synthesize PODE in a fixed-bed reactor. Temperature and space velocity had little effect on the conversion of trioxane and the selectivity of PODE under the conditions examined. When the reaction temperature was 85℃ and space velocity was 5h^-1 in the fixed-bed reactor, the extruded ZSM-5 catalyst showed excellent stability in a 240h test, and the conversion of trioxane was higher than 90%, and the selectivity of PODE_2~8 was above 95%.

The production of bio-jet fuel from biological deoxygenated oil has great application potential and development prospects. To improve the yield of bio-jet fuel, it is essential to develop high-performance catalysts for the hydrocracking and hydroisomerization. After low-temperature aging, adding seeds or increasing the alkalinity of the initial gel and crystallization, small size ZSM-22 zeolites were obtained with the average c-axis size between 100—330nm. The samples were characterized by XRD, SEM, N₂ physical adsorption, NH₃-TPD and Py-IR. Catalysts prepared by ZSM-22 with different crystal sizes were evaluated on the cracking and isomerization of long-chain normal bio-paraffins from hydrodeoxygenated biomass oil to bio-jet fuel. The results indicated that, the small crystal size H-ZSM-22 synthesized by increasing alkalinity of gel had stronger acid centers and more accessible strong B acid centers. The conversion of long-chain normal bio-paraffins were more than 80%. Further, the Pt/ZSM-22 catalyst possessed high Pt dispersion and exhibited great hydrocracking and isomerization performance. The conversion reached 97.79%, and the yield of bio-jet fuel was as high as 50.25% with an iso/n-paraffin ratio of 7.55.

Since the first report of layered black phosphorus (BP) in 2014, it has become a new member of two-dimensional nanomaterials and received extensive research attention. Due to the large specific surface area, adjustable band gaps, high carrier mobility, good biocompatibility and easy accessibility for functionalization, BP can serve as a promising candidate for biosensing material. In this review, a survey on the BP-based electrochemical sensors is provided, which are classified according to the type of analytes, including gas molecules, small biological molecules, other small molecules, large biological molecules and cells. Specifically, the preparation methods and properties of BP and its composites, as well as the structure, sensing mechanism and analytical performance of these BP-based electrochemical sensors are comprehensively summarized. Finally, the current challenges and future prospects of the application of BP-based nanomaterials in electrochemical sensors are discussed, which provided a perspective on the further applications of BP nanomaterials in the field of chem- and bio-sensing.

Two-dimensional nanomaterials have high mechanical strength and specific surface area, a large number of surface functional groups, good hydrophilicity and biocompatibility, and are good carriers for enzyme immobilization. In this paper, classical graphene oxide (GO) and new transition metal carbon/nitrogen compounds (MXenes) were selected, and their preparation methods, structure, physical and chemical properties were introduced respectively. Their applications in the field of enzyme immobilization were reviewed and compared. GO is prepared from graphene by chemical oxidation and then peeled. MXene is prepared from its precursor by etching. Materials prepared by different oxidation or etching methods have differences in composition, structure and properties. There are more reactive functional groups on GO surface, including hydroxyl, carboxyl and epoxy groups, so it is widely used in the field of enzyme immobilization. Enzyme is immobilized on MXenes mainly by the reaction with hydroxyl groups or the adsorption on the negative charges on the surface, and current major application is in biosensors. At last, it is pointed out that there are still some problems for the two kinds of materials, such as low preparation efficiency, easy agglomeration of nanosheets and poor recyclability. The future development directions are to develop simpler and safer material preparation methods, explore more effective means of intercalation and stripping, and improve the recycling strategies of the immobilized enzymes, so as to further promote the application of two-dimensional nanomaterials in the field of enzyme immobilization.

Magnesium sulfate heptahydrate is an inorganic salt hydrate chemical heat storage material with high heat storage density (2.8GJ/m³) and low working temperature (<150℃). The development of high-efficiency thermochemical heat storage materials and heat storage systems based on magnesium sulfate heptahydrate is expected to achieve good energy-saving and emission-reduction application effects in the fields of solar thermal utilization, industrial waste heat recovery, seasonal energy storage and building heating. This article introduces in detail the heat storage principle and basic physical properties of magnesium sulfate heptahydrate. Magnesium sulfate heptahydrate faces the shortcomings such as large mass transfer resistance, limited service life, insufficient heat transfer performance, etc. Therefore, the methods to prepare high-performance composite materials are introduced by modifying magnesium sulfate with zeolite, polymer foam and carbon materials, as well as the performance of the thermal storage unit. The paper points out the future development trend of magnesium sulfate heptahydrate for thermochemical storage and application.

Carbon aerogel is a kind of porous carbon nano materials with low density, high porosity, high specific surface area, excellent electrical conductivity and good mechanical properties. Therefore, it has become a hot spot and an important direction in the research of carbon materials. The purpose of this paper is to elucidate the development process of phenolic carbon aerogels and to highlight the development direction of phenolic carbon aerogels in the future. Based on this, the preparation methods of phenolic carbon aerogel are introduced in detail firstly, including three main steps: sol-gel, drying and carbonization process. Furthermore, the preparation of phenolic carbon aerogels with three different precursors, namely resorcinol, phenol and biomass tannin/lignin, as well as their advantages and disadvantages are described. Then, the applications of phenolic carbon aerogels as adsorption materials (gas/liquid adsorption), electrochemical energy storage materials and also for other fields are reviewed. Finally, the research direction and development prospect of phenolic carbon aerogels are summarized and prospected. It is pointed out that the traditional method of preparing phenolic carbon aerogel with resorcinol as raw material by supercritical drying method had high raw material cost and harsh reaction conditions, which limited its practical production and application. Replacing resorcinol with phenol or improving its preparation process by freeze-drying method can greatly reduce the raw material and production costs. However, the future development direction would be the systematic research of green and renewable biomass raw materials (tannin, lignin, cashew phenol, etc.) and the development of their composite materials. Therefore, in the future development of phenolic carbon aerogels, it is necessary to further improve the preparation process and method and broaden the source of raw materials to improve the performance and expand the application field.

With the trend of global warming, environmental pollution is worsening and the development of energy-saving technology is imminent. Radiative cooling materials have attracted increasing attention over the world because of their excellent heat-sinking capability without consuming energy. However, complicated preparation process, high cost and poor weather resistance limite their practical application. At present, the optimization of the properties of various radiation cooling materials becomes a hot issue. Based on the mechanism of radiation cooling, the research progress of several radiative cooling materials and their current limitations are reviewed. Finally, the development trend of radiative cooling materials is prospected. It is pointed out that the main research directions in the future are to combine different types of radiative cooling materials reasonably and to evaluate the radiative cooling properties of materials according to the local environmental characteristics. The research on the radiative cooling materials can make great contributions to China’s energy conservation and emission reduction industry.

Magnetic hydrothermal carbon, which has the advantages of both adsorption property of hydrothermal carbon and recovery of magnetic material, is a kind of water treatment adsorption material with broad application prospect. At present, the preparation of magnetic hydrothermal carbon by two-step method is more complicated. Therefore, this paper used Pinus Massoniana sawdust as raw material, FeSO₄ as magnetizing agent, NaOH as activating agent, and 1,2-propanediol as reducing agent, and developed one-step preparation technology of magnetic hydrothermal carbon. The effects of reaction temperature and time on the yield and structure of magnetic hydrothermal carbon were investigated. The products were characterized by XRD, SEM, BET, VSM. The results showed that with the increase of reaction temperature and reaction time, the yield of magnetic hydrothermal carbon decreases gradually, but the specific surface area and the magnetism increase. The magnetic hydrothermal carbon prepared from Masson Pine under 240℃ and reaction time of 8 hours had good adsorption performance and magnetism, the amount of Cu²⁺ adsorbed by magnetic hydrothermal carbon was 9.58mg/g, and the maximum saturation magnetization was 3.74emu/g, which had good application potential.

Using cyclodextrin as raw material, activated carbon with high specific surface area and abundant pore structure were obtained by carbonization-activation method. Keeping activation time and activation temperature as constant, the pore structure and electrochemical performance of activated carbon in different alkali-carbon ratio (KOH/C) were investigated. Increasing the dosage of KOH, the surface area, total pore volume and specific capacitance of the samples all indicated a trend of first increasing and then decreasing. When the alkali-carbon ratio was 3, the prepared sample showed the best capacitance performance. This sample had the highest value of specific surface area (1672m²/g), and highest value of total pore volume (0.75m³/g). Moreover, the specific capacitance of the sample can reach 165F/g at 1A/g current density, which was better than commercial activated carbon 21KSN (140F/g) under the same condition, and its capacity retention rate was still 98.7% after 50000 cycles.

Aiming at the recovery and removal of residual solvents in the solvent extraction residues of heavy oil mines, a surfactant-enhanced bubbling separation process based on the bubbling separation process was proposed. The influence of surfactant types on the bubbling separation process was explored, and the kinetics of the anionic surfactant sodium dodecyl sulfate (SDS) on the bubbling separation process was studied. The results showed that the type of surfactant has an important influence on the removal effect. By reducing the toluene-water interfacial tension and increasing the hydrophilicity of the solid surface, the anionic surfactant SDS promoted the separation of the toluene liquid layer from the surface of the solid particles, thereby strengthening the bubbling separation process. The first-order kinetic model of the process was confirmed. However, the cationic surfactant tetradecyl trimethyl ammonium bromide (C₁₄TAB) and the amphiphilic surfactant lauryl betaine (SB-12) increased the hydrophobicity of the solid surface, which promoted the particled to leave the solution system and inhibited the progress of bubbling separation. But the degree of SB-12 modification on the solid surface was weaker than that of C₁₄TAB, so the inhibitory effect of SB-12 was weaker than that of C₁₄TAB. With the extension of the bubbling time, the change of toluene-water interfacial tension caused by SB-12 became the main factor affecting the effect of bubbling separation, the effect of SB-12 on the bubbling separation process changed from inhibition to enhancement. But C₁₄TAB always exhibited an inhibitory effect during the bubbling separation process. The above results had certain theoretical significance for the removal and recovery of residual solvents after similar solid-phase solvent extraction.

In order to solve the problem of high brittleness and poor toughness of cement-based materials, a method of doping redispersible emulsified asphalt powder (REAP) to improve the toughness of cement-based materials was presented. The redispersible emulsified asphalt particle modified cement mortar (REAPMCM) was prepared, and the REAP contents were 0, 10%, 20% and 30% of the cementitious material, respectively. The effects of REAP on the mechanical properties of REAPMCM, such as compressive strength, flexural strength, flexural-compression ratio and elastic modulus, were studied. The effects of REAP on the micromorphology of cement hydration products were analyzed, and the micromorphology of cement emulsified asphalt mortar prepared with emulsified asphalt was compared. The results showed that with the increase of REAP content, the compressive, flexural strength and elastic modulus of REAPMCM were reduced, and the flexural-compression ratio was increased. The flexural-compression ratio of REAPMCM with 30% REAP was 28.5%, which was 46.6% higher than that without REAP. The addition of REAP improved the toughness of cement-based materials, but as the age of cement hydration increased, its improvement effect decreased. As the amount of REAP increased, the total porosity of the slurry and the asphalt film area between cement hydration products increased, and its section micromorphology was basically similar to that of emulsified asphalt mortar with the same asphalt solid content. It was proved that REAP also had good dispersibility and can be distributed in the cement hydration product as a film, achieving similar application effect as the modification of cement-based materials by emulsified asphalt emulsion.

Enzyme@ZIF-8/PAM-AA microparticles with excellent catalytic, storage and environmental tolerance properties, were synthesized by in situ growth of enzyme@ZIF-8 nanoparticles via biomineralization on uniform polyacrylamide-co-acrylic acid hydrogel (PAM-AA) microparticles from microfluidics. The microparticles showed average sizes of 559.97μm, with CV value of 2.17%, exhibiting good monodispersity. The enzyme@ZIF-8 nanoparticles mainly grew in situ on the microparticle surface, which facilitated their effective contact with the substrates for catalytic reaction. The catalytic performance of the microparticles was studied by using hydrogen peroxidase as the typical enzyme. The results showed that, the microparticles exhibited good catalytic performance, as well as good storage properties and environmental tolerance.The microparticles maintained about 75% of relative activity after treatment with 80℃ water, UV irradiation and trypsin for 30 min, respectively. Moreover, their enzymatic activity remained nearly unchanged after stored at room temperature for 7 days. This work provided a new strategy for design and fabrication of novel advanced functional microparticles for enzyme immobilization.

In order to reasonably explore the method of intelligence to the luminescent polyurethane, the flexible luminescent polyurethane composite (LPC) with thermochromic function was prepared by coating finishing. The surface roughness of the material was observed by scanning electron microscope (SEM). X-ray diffractometer (XRD) analysis showed that the coating process and the addition of pigments did not affect the phase structure of the rare earth luminescent materials. The reflectance and emission spectra indicated that the material has excellent thermochromic luminescence characteristics. Under standard light source, the color of material itself can be changed by body temperature (from red to white). After excited by ultraviolet-visible light source, the system of low-temperature red light and high-temperature white light was formed in dark environment, which fully demonstrated its application potential in the field of smart wearable devices.

Nitrogen-doped carbon nanotubes (NCNT) were prepared by introducing nitrogen-containing groups into surface of carbon nanotubes of different wall numbers using the pre-oxidation treatment and the ammonia hydrothermal method. Effect of carbon nanotube wall number on the electro-catalytic activity of NCNT for oxygen reduction reaction (ORR) was investigated. X-ray photoelectronic spectroscopy showed that the nitrogen content and the types of nitrogen-containing groups of each NCNT was similar. On the contrary, the content of different nitrogen-containing groups in each NCNT was quite different. Among them, the NCNT sample with an average wall number of 2.5 exhibited the lowest contents of pyridine nitrogen and graphite nitrogen, whereas it exhibited the highest ORR activity in terms of the most positive half-wave potential and the highest limiting current density. This indicated that the ORR activity of NCNT was decided by the number of walls of NCNT, rather than that of pyridine nitrogen and graphite nitrogen active groups when the samples had the similar nitrogen content. For this sample, the inner layer provided an effective conductive path to transfer electrons from the inner layer to the outer layer through the tunneling effect, and then the active sites of the nitrogen-containing groups on the outer wall converted O₂ to OH^-. Nevertheless, the tunneling effect became weaker with increasing the wall number of NCNT, leading to the decrease of the ORR activity of NCNT.

As a potential material for thermal energy storage and thermal management, phase change material (PCM) has a reasonable energy storage density and a negligible temperature variation, where undergoing low thermal conductivity leads to poor thermal transfer efficiency. In this study, copper foam was used to enhance the thermal properties of paraffin. By measuring the temperature variation during the heating and cooling process of PCM, the effect of adding copper foam on the heat storage and release rate and temperature uniformity was investigated. On the basis of experiments, the heat release model of PCM was established and solved, and the temperature cloud diagram was obtained which could provide better guidance for the practical applications of PCMs. The results showed that after adding copper foam, the latent heat storage and release time of paraffin were reduced by 16.67% and 14.71%, respectively. The maximum temperature difference between the center point of the center layer and the outer layer during the heating and cooling process was reduced by 91.5% and 87.5%, respectively. The model of temperature change with time in the exothermic process of PCM was established. The correlation coefficient and standard error were 0.99℃ and 0.13℃, respectively by comparing the actual value with the predicted value, which proved that the model had high accuracy and could effectively predict the temperature change of PCM.

Aspartate transcarbamylase (ATCase) is the first enzyme in the pyrimidine biosynthesis pathway, and the feedback regulation mechanism of its activity plays an important role in controlling the balance of purine and pyrimidine metabolism. Currently, the activity of ATCase is detected through a spectrophotometric method with antipyrine and 2,3-butanedione oxime as the color reagent. However, this method requires a reaction in the darkness for 16h, and then a water bath at 45℃ for 30min with uniform illumination, which is complicated to operate. In this study, p-dimethylaminobenzaldehyde (PDAB) hydrochloric acid solution was used as the color reagent to establish a method for detecting the activity of ATCase. The principle of this method is that N-carbamoyl-L-aspartic acid (the product of ATCase) reacts with PDAB at room temperature for 15min, which can produce a yellow substance and can be quantitatively detected by colorimetry. In the range of 0.1—5mmol/L, the yellow color deepened with the increase of the N-CP-DL-Asp concentration, and the absorbance at 438nm had a good linear relationship. The precision RSD was 0.87%—1.52%, and the recovery rate of standard addition was 96.6%—101.9%. This method was successfully used to determine the activity of recombinantly expressed ATCase, and the specific activity was 56.83U/mg. This method realizes the efficient, rapid and visual detection of the activity of ATCase, and can achieve high-throughput detection by using a microplate reader.

The salinity in food waste has an adverse effect on its anaerobic digestion and methane production. In order to solve this problem, the effects of iron-carbon microbial electrolytic cells on the thermophilic anaerobic digestion were studied. Zero-valent iron was used for the anode of the microbial electrolytic cells to improve the salt tolerance of microorganisms and enhance the oxidation of organics, thereby promoting the methane production. The results show that the maximum cumulative methane yield of the iron-carbon microbial electrolytic cells reaches 1110.67mL, which increases 68.18% compared to the control group. With the increase of Na⁺ concentration, the hydrolysis and acidification process is inhibited, and the iron-carbon microbial electrolytic cells promote the process of microbial degradation of organics and the process of converting propionic acid and butyric acid into acetic acid. From the microbiological analysis,the abundance of Methanomassiliicoccus in the iron-carbon microbial electrolytic cells group is enhanced, accounting for 52% of the anode. Metabolic pathway analysis shows that the iron-carbon microbial electrolytic cells improve the salt tolerance of microorganisms, promote the hydrolysis and acidification process and increase the gene abundance of enzymes in the process of acetic acid decarboxylation and CO₂ reduction in the process of methanogenesis. Iron-carbon microbial electrolytic cells are beneficial to the anaerobic digestion of food waste.

In order to improve the leaf deposition rate of avermectin and its resistance to UV decomposition, a foliar affinity nanocarrier was designed. By free radical polymerization, dimethyldiallylammonium chloride (PDMDAAC) was used to modify Zein, and the modified Zein with positive charge on the surface was obtained, which was used to load avermectin. The drug-carrying nanoparticles with an average particle size of 64.92nm were prepared by anti-solvent precipitation method. The encapsulation efficiency of avermectin was (34.75±0.18)%. The electrostatic interaction with the plant surface improved the wettability of the suspension, and the contact angle decreased from 77.38° to 64.60° with the increase of the amount of PDMDAAC grafting. Leaf retention reached 33.69mg/cm². Avermectin coated with modified Zein improved the UV resistance, the half-life was extended from 15min to 40min, and the release rate of avermectin was regulated by the grafting rate of PDMDAAC.

The interaction between octyl phenyl polyoxyethylene ether (Triton X-114) and fatty alcohol polyoxyethylene ether (AEO-9) could significantly affect the ultraviolet spectrum of Triton X-114 in aqueous solution. The experimental results indicated that the maximum absorption wavelength of Triton X-114 was 223nm in the range of 200—350nm, and the ultraviolet absorbance of AEO-9 was close to 0. In aqueous solution, AEO-9 can decrease the UV absorbance of Triton X-114 by 3.4%. AEO-9 also significantly decreased the apparent critical micelle concentration (cmc) of Triton X-114 from 0.219mmol/L to 0.207mmol/L and 0.202mmol/L, respectively when the concentration of AEO-9 increased from 0 to 0.050mmol/L and 0.100mmol/L. Experimental results further showed that β-cyclodextrin (β-CD) can effectively reduce the AEO-9 on the ultraviolet absorbance of the Triton X-114 and the influence of apparent cmc. When the Triton X-114 and AEO-9 distribution in aqueous solution with the amount of substance ratio 1∶1 to join the β-CD, the recovery of Triton X-114 in the mixed aqueous solution changed from 95.8%—103.3% to 99.0%—100.1%. It was suggested that the β-CD can significantly reduce the interference of AEO-9 on Triton X-114. The results of Fourier transform infrared spectroscopy analysis (FTIR), nuclearmagnetic resonance hydrogen spectrum (¹H NMR) analysis and thermogravimetric-differential thermal analysis (TG-DSC) showed that Triton X-114 entered β-CD molecular cavity and formed inclusion, which was the main reason for blocking the formation of mixed micelles of Triton X-114 molecule and eliminating the interference of AEO-9 to Triton X-114.

A series of KF/MgO catalysts were prepared from the high temperature impregnated KF/MgCO₃ precursor, and then employed as solid base catalysts for the transesterification of dimethyl carbonate (DMC) and glycerol (GL) to glycerol carbonate (GC). The effects of KF content and calcination temperature on the catalytic performance were systematically investigated, and the structure of these catalysts were characterized by XRD, N₂ adsorption-desorption, SEM and Hammett acid-base titration. The 20%KF/MgO-550 sample calcinated at 550℃ with 20%KF loading was found to be the best catalyst for this reaction. The highest GC yield of 96.8% were obtained at the optimum reaction conditions of molar ratio of DMC to GL 3∶1, catalyst dosage of 2.0% (relative to GL mass), 75℃, and 1.5h reaction time. The GC yield over 20%KF/MgO-550 could drop from 96.8% to 67.3% in the third run, but the catalytic activity can be restored with more excellent stability after regeneration.

Chemical solvent absorption is currently the most effective CO₂ capture technology, and organic amines are commonly used as absorbents. However, its application in industry is limited due to its high regeneration energy consumption and high cost. Phase-change absorbers developed on the basis of traditional organic amine solvents are considered to be able to significantly reduce the energy consumption of desorption, which has become a research hotspot in recent years. In this paper, the common types and phase separation mechanism of phase change absorbers are introduced in detail, and the types are classified according to their specific composition. The regeneration energy consumption of the common phase-change absorbent and the traditional MEA absorbent is compared and analyzed. It also points out the influence of temperature, CO₂ load and phase separation on the long-term stability of the process flow of the phase change absorbent. In the process of preparing phase change absorber, an activator can be added to reduce the viscosity of CO₂ rich liquid, and a cosolvent can be added to improve the mass transfer characteristics. The research status of volatilization, degradation and corrosion characteristics of phase-change absorbent is reviewed. Finally, some suggestions on the future research direction of phase-change absorbers are given based on the research status and the requirements of flue gas capture.

Brackish water electrodialysis desalination technology has the advantages of excellent desalination performance, low cost, and environmental protection. However, there are some problems such as complex membrane preparation process, imprecise mass transfer model, and energy efficiency which needs to be improved. This article first analyzes the preparation and modification methods of the brackish water electrodialysis ion exchange membrane, and discusse the problems in membrane materials. Secondly, the principle and latest progress of brackish water electrodialysis in simplified model, theoretical model and semi-empirical model are compared and summarized. Both the operation mode and process optimization strategy of conventional brackish water electrodialysis are summarized systematically. The principle and application of new electrodialysis processes in brackish water desalination, such as new electrodeionization, shock electrodialysis and renewable energy driven electrodialysis, are further introduced. Future works will focus on reducing the cost of membrane preparation, optimizing mass transfer model, exploring integrated membrane desalination process and new electrodialysis process.

The effective green regeneration of saturated activated carbon is very important for the recycling of activated carbon in the process of pollutant adsorption. In this paper, the method of ultrasonic assisted melting oxalic acid was used to regenerate the saturated activated carbon with high efficiency and green. The effects of temperature, time, ultrasonic amplitude and solid-liquid ratio on the regeneration efficiency of saturated activated carbon were discussed. The results showed that the saturated activated carbon can be regenerated rapidly in 20 minutes by molten oxalic acid under the assistance of ultrasound and the regeneration efficiency was as high as 94.72%. After five adsorption desorption cycles, the regeneration efficiency can still reach 78.02% and the recovery rate of organic acids was very high with an average of 98.35%, and thus green regeneration was realized. Under the assistance of ultrasound, the molten oxalic acid with strong hydrogen bond association ability reacted more fully with caramel to form a strong hydrogen bond association system between oxalic acid and caramel, which reduced the affinity between caramel and activated carbon surface. Then, the adsorbate can be desorbed to achieve the regeneration of the activated carbon. This method can provide a new idea for the research and development of green and efficient activated carbon regeneration method.

In order to more intuitively study the mechanism of the flow electrode capacitive deionization (FCDI) ammonia removal process and make efficient improvements, an electrochemical steady-state model for the removal of ammonium ions by the FCDI device was constructed, and the simulation accuracy of the experimental results reached 93.8%. The model was used to study the energy consumption and removal efficiency change trend of the FCDI ammonia removal process under the conditions of inlet water flow, current density, and active carbon mass fraction in the electrode solution. Two indicators of ion selectivity and removal rate were calculated which qualitatively explained the influence mechanism of operating parameters on the removal of ammonia to optimize working conditions. The results showed that when the FCDI ammonia removal process has an inlet water flow of 1.25mL/min, a current density of 21.26A/m², and an activated carbon mass fraction in the electrode solution of 10%, the ammonia removal efficiency is 74.5%, and the energy consumption is 29.62kWh/kg N, which has reached the comparatively ideal result. Under the optimized working conditions, the situation that the microscopic transmission of ammonium ions in the FCDI device was discussed. Considering that the excessively long flow channel length would increase the polarization of the current and reduce the ammonia removal performance of the device, suggestions for series installation were put forward. Keeping the length of the flow channel and the working conditions unchanged, the series-connected device can increase the removal efficiency by 32.9% compared with the original device, and at the same time can reduce the energy consumption per unit mass of N by 22.0%, indicating that the improvement of the device is effective. The optimized FCDI ammonia removal process with higher ammonium ions removal efficiency, lower energy consumption, and broad application prospects has more advantages than similar treatment processes.

N,N-dimethylethanolamine (DMEA) is a promising absorbent because of its fast reaction rate and high CO₂ trapping ability. In this study, DMEA, as a new type of absorbent, was used in hollow fiber membrane contactors to separate CO₂ from CO₂/CH₄ gas mixtures. A two-dimensional steady-state mathematical model was established to simulate the effects of MEA (monoethanolamine), DEA (diethanolamine), MDEA (N-methyldiethanolamine) and DMEA on the absorption properties of CO₂ under different operating conditions. The results showed that the decarbonization performance was MEA>DMEA>DEA>MDEA, the effect of gas phase parameters on decarbonization rate was more significant than liquid phase parameters, the decarbonization rate decreased with the increase of gas flow rate and CO₂ concentration, the decarbonization rate increased with the increase of liquid velocity and absorbent concentration, and the removal efficiency of CO₂ can be improved by properly increasing absorbent flow rate and absorbent concentration. In addition, the CO₂ absorption flux will increase with the increase of gas velocity and decrease with the increase of CO₂ load in the liquid phase. Finally, through the joint action of two influencing factors, the best operating conditions of membrane contactor for acid gas separation were determined. Therefore, membrane absorption had good potential in natural gas decarbonization.

Plastic products have been widely used because of their advantages of light weight and stable nature, but most waste plastics have not been properly recycled and become pollutants, causing harm to the environment. Therefore, recycling and reprocessing of waste plastics have become an effective way to protect the environment and utilize the resources. Separation is an important link for waste plastics to be reprocessed. At present, a variety of separation methods have been developed, among which plastic flotation method is favored by people because of its simple process and less pollution. However, in plastic flotation, the surface hydrophilicity and hydrophobicity are affected by the environment, which further deteriorates the separation effect. In order to avoid the fluctuation of separation process, it is urgent to explore the effect of environmental factors on hydrophilicity and hydrophobicity. Based on this, this paper selected three kinds of waste plastics, namely ABS, PC and PS, to explore the influence of environment on flotation separation and surface hydrophilic and hydrophobic group reconstruction. The results showed that when ABS, PC and PS after oxidation modification were in polar environment, the floatability of the plastics remained unchanged, the contact angle fluctuated slightly, and the surface remained hydrophilic. In the ethanol environment, the floatability of plastics increased, the contact angle rose to about 75°, and the recovery speed of surface hydrophobicity was faster than that of polar environment. In the non-polar environment, the floatability of the plastic enhanced faster, while the surface was completely restored to the hydrophobicity before modification. In the polar environment, the hydrophilic groups were more likely to stay on the surface. With the decrease of polarity, the hydrophilic groups gradually migrated to the body and the plastic surface resumed to be hydrophobic. Therefore, polar environment was more conducive to maintaining hydrophilic surface of plastics.

The production of high-quality synthetic gas from municipal sludge turns out to be an effective solution in terms of lower environment pollution, higher added value of waste and realizing energy utilization. By using dielectric barrier discharge non-thermal plasma (NTP-DBD) technology, urban sludge and its model compounds, i.e. leucine and glucose, were gasified. The effects of different atmospheres and discharge frequencies on gas generation characteristics were studied. The solid products were subjected to Fourier infrared (FTIR), scanning electron microscope (SEM) for characterization. The results showed that the syngas concentration produced by NTP-DBD gasification sludge was increased by 1.84% compared with that of thermal gravimetric wastewater in Ar. When the discharge frequency was adjusted from 10.5kHz to 9.2kHz, the output voltage was increased by 36%, and the sludge gasification rate was increased by 5 times. When the ambient gas was CO₂, the gasification efficiency accounted for 74.86% of the volatile content of the sludge. Leucine gasification produced more H₂, CO, CO₂ and CH₄, indicating that the protein in the sludge contributes more to the gas products of sludge gasification. Compared with the performance of ordinary pyrolysis, the NTP gasification technology can not only effectively increase syngas capacity, but also ease high temperature operation and avoid the formation of highly toxic substances such as dioxins during sludge gasification.

Electrolytic manganese residue (EMR) stored in the residue yard contains a large amount of manganese (Mn²⁺) and ammonia nitrogen (NH{}_{\mathrm{4}}^{+}-N), which can easily migrate and pollute the surrounding environment. Therefore, the physical and chemical properties of EMR with different storage time (3 months to 10 years), such as pH, water content, conductivity, total metal content, leaching toxicity, chemical morphology and phase structure, were systematically studied. The phase composition, micro morphology and surface electronic valence of EMR with different storage time were analyzed by XRD, SEM and XPS. The results showed that with the storage time increased, pH, the water content, electrical conductivity and the contents of soluble Mn²⁺, Ca²⁺, Mg²⁺, Se⁴⁺ and NH{}_{\mathrm{4}}^{+}-N decreased. Exchangeable and carbonates bound Mn were the main forms of Mn loss. EMR stored for 10 years still had a great risk of environmental pollution. The total amount of Cu, Cr, Cd, Pb, and Zn far exceeded the background value of Guangxi soil. The leaching concentration of Se⁴⁺ was 11 times of the concentration limit in 《Identification standards for hazardous wastes—Identification for extraction toxicity》 (GB 5085.3—2007). The leaching concentration of Mn²⁺ and NH{}_{\mathrm{4}}^{+}-N were 102 times and 45 times of the first class standard limit of 《Integrated wastewater discharge standard》 (GB/T 8978—1996). The main forms of Mn²⁺ and NH{}_{\mathrm{4}}^{+}-N in EMR with different storage time were (NH₄)(Mn,Ca,Mg)PO₄·H₂O, (NH₄)₂SO₄, MnSO₄·H₂O, MnCO₃, Mn₂O₃ and MnO₂. Iron-containing phases mainly included FeS₂, FeOOH, Fe₃O₄ and Fe₂O₃. And it also contained clay minerals, including Al₄(OH)₈(Si₄O₁₀), Al₂Mg₄(OH)₁₂(CO₃)·3H₂O and KAl(SO₄)₂·12H₂O. In addition, with increasing storage time, the average pore size of EMR decreased, and the phenomenon of crisscross inclusion of massive, columnar and ball like particles increased. The Fe(OH)₃ colloid particles gradually transformed into FeOOH, Fe₂O₃ and other iron-containing phases. The research results provided basic theoretical support for the harmless treatment and resource utilization of EMR.

Chemical oxidation can rapidly and efficiently repair oil contaminated soil, but little attention has been paid to its impact on soil quality and environmental risk of residual pollutants. In this study, sodium percarbonate (SPC) was used as oxidant and citric acid (CA)/ferrous sulfate [Fe(Ⅱ)] as catalyst. The remediation efficiency of activated sodium percarbonate for diesel contaminated soil and the degradation characteristics of different components in diesel were analyzed. The changes of pH availability and biotoxicity of extracts indicated the environmental risk of different treatments. The changes of soil characteristics before and after remediation were analyzed by organic carbon and FTIR. The results showed that the efficiency of SPC alone was low, and CA/Fe(Ⅱ) significantly increased the removal rate of TPH. FTIR spectra indicated that the vibration of Si—O—Si, C—H and —OH increased after treatment. GC/MS analysis exhibited that the main component of TPH was long chain alkanes (C₁₆—C₂₁). The inhibition rate of luminescent bacteria in extract of hydroxypropyl-β-cyclodextrin (HPCD) increased with the increase of pH, indicating that the strong alkalinity produced by excessive SPC dosage had a significant effect on soil biotoxicity. The increase of CA dosage can promote the removal rate of TPH more than SPC and FeSO₄, and help to reduce the bioavailability of residual TPH and improve the content of TOC in soil. Environmental risk analysis and optimization of remediation conditions should be carried out for remediation of organic contaminated soil by chemical oxidation.

Novel moving bed biofilm reactor (MBBR) was constructed by adding magnetic carriers (named by R2) in order to enhance the cold resistance of biofilm and improve the nitrification performance of MBBR at low temperature. Meanwhile, the traditional MBBR with commercial carriers was taken as the control group (named by R1). R1 and R2 were operated at various temperatures (14℃±1℃ and 9℃±1℃) for a long time. The effects of magnetic carrier on the pollutants removal performance and biofilm growth characteristics in MBBR were investigated at low temperature. In addition, the high-throughput sequencing technology was used to explore the microbial response relation in biofilm. The results showed that the COD and ammonium removal efficiency of R2 was better than R1 during the whole low temperature operation period (0—60d). At 9℃±1℃, the ammonium average concentration of effluent of R1 and R2 were 11.94mg/L and 7.60mg/L, respectively. The ammonium removal rate of R2 was 16.2% higher than that of R1. At low temperature, magnetic carrier significantly improved biofilm nitrification activity. And magnetic carrier promoted the secretion of extracellular polymeric substances (EPS) in biofilm, which maintained and improved the structure of biofilm. Moreover, high-throughput sequencing results showed that there were significant differences in biofilm microbial community structure among different carriers at 9℃±1℃. Most dominant genera in the two carriers could degrade organic matter. More nitrifiers were found in magnetic carrier. The relative abundance of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were increased by 1.82 and 1.05 times, respectively, compared to the commercial carrier. Furthermore, Nitrifiers (MND1and Candidatus_Nitrotoga)were found only in magnetic carrier. The study explained the difference of ammonium removal efficiency between the two reactors from the point of biofilm characteristics and nitrifiers abundance, which showed that magnetic carriers MBBR has better nitrification performance at low temperature.

In order to remove nitrogen and phosphorus from municipal wastewater and nitrate wastewater economically and efficiently, denitrifying phosphorus removal (DPR) and partial denitrification Anammox (PDA) processes were established in an Anaerobic Baffled Reactor (ABR) and Continuous Stirred Tank Reactor (CSTR) integrated reactor, respectively. Results showed that the removal efficiencies of PO{}_{\mathrm{4}}^{\mathrm{3}-}-P and TN were 96.91% and 97.75%, respectively, under the conditions of anoxic/anaerobic and external COD/NO₃^--N ratio of 0.7 after 185 days of operation. The final effluent PO{}_{\mathrm{4}}^{\mathrm{3}-}-P and TN concentrations were as low as 0.22mg/L and 3.30mg/L, respectively, which indicated that the excellent nitrogen and phosphorus removal efficiency of the system independent of oxygen and organic carbon sources. The removal of PO{}_{\mathrm{4}}^{\mathrm{3}-}-P and TN by DPR accounted for 99.07% and 60.23% of the total, respectively, while the proportion of TN removal by PDA increased gradually (4.53%→37.52%). Batch experiments showed that, ①high concentration of COD (300mg/L) significantly inhibited the activity of DPR bacteria, and PO{}_{\mathrm{4}}^{\mathrm{3}-}-P was mainly removed by DPR with NO{}_{\mathrm{3}}^{-}-N as electron acceptor and organic matter as electron donor under anoxic condition; ②the highly-efficient partial denitrification process (NTR 92.25%) supplied stable electron acceptor (NO{}_{\mathrm{2}}^{-}-N) for anammox, andthe residual NH{}_{\mathrm{4}}^{+}-N of DPR system was mainly eliminated by NO{}_{\mathrm{2}}^{-}-N oxidation. Therefore, the DPR+PDA system had achieved the high-efficiency and synchronous nitrogen and phosphorus removal effect. High throughput sequencing showed that Accumulibacter (7.41%) was the functional phosphorus removal bacteria in DPR system, and Thauera (7.24%) and Candidatus Brocadia (3.12%) were the key nitrogen removal bacteria in PDA system.

The successive processes including physicochemical units (oil separation+air flotation)+biofilter (BAF)+hydrolysis acidification (HA)+anoxic/oxic (A/O)+oxic-membrane bioreactor (O-MBR)+catalytic ozonation (COP) were used to treat heavy oil refining saline wastewater. The organics degradation characteristics along treatment processes were comprehensively analyzed by GC-MS combined FT-ICR MS. Small molecular organic acids, esters, aldehydes and ketones were dominantly degraded by BAF. HA showed very weak degradation towards organics. Most O₂ species and all N₁O₂S₁ species were degraded by A/O. The O₃S₁ and N₁O₃ species, penetrated from O-MBR, were completely mineralized by COP. The residual COD in the final effluent mainly were macromolecular saturated fatty acid and naphthenic acid with high unsaturation degree. The results may guide the assessment and optimization of heavy oil refinery wastewater treatment plant.

Glucocorticoids (GCs), as a kind of environmental endocrine disruptors, have attracted increasing attention in the field of environment. Due to the lack of technology to effectively control GC pollution in water, this research built a paralleling plasma jet/activated carbon fiber (PPJ/ACF) system to effectively degrade fluocinolone acetonide (FA). At PPJ discharge power of 49.7W and ACF dosage of 3g/L, the removal efficiency of FA reached 96% at 60min with energy yield of 96mg/kWh and energy consumption of 0.36kWh/L. The combination of PPJ and ACF showed significant synergistic effects. During PPJ treatment, the added ACF provided catalytic sites and adsorption sites for GCs. In the meantime, PPJ released ACF adsorption sites in situ. In PPJ/ACF system, hydroxyl radicals (·OH) were identified as the functional reactive species for FA degradation by radical scavengers. Transformation intermediates with lower lipophilicity and toxicity were identified by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (UHPLC-QTOF), indicating possible degradation pathways of FA including defluorination, keto acid decarboxylation, demethylation, intramolecular cyclization, cleavage and esterolysis. Overall, this study provides an effective and practical way to control GC pollution by PPJ/ACF treatment.

The effects of different temperatures (120—200℃) and treatment times (15—90min) on the migration transformation and environmental risks of heavy metals (Cr, Mn, Ni, Cu, Cd and Pb) in sludge were investigated by analyzing the changes of heavy metal content and morphology during sludge thermal hydrolysis treatment, and the correlation between physicochemical parameters (VS, soluble protein, polysaccharide, SCOD, alkalinity, ammonia-N, and pH) and changes of heavy metal bioavailability was analyzed. The results showed that the sludge was effectively cracked by thermal hydrolysis, and some of the heavy metals were released into liquid phase, but most of them remained in solid phase. The contents of Cr and Mn in the solid phase increased at higher treatment temperatures (≥180℃) compared to those in the original sludge, while the contents of other heavy metals decreased. Most of the heavy metals (except Pb) in weak acid extracted fraction in sludge showed a decreasing trend with increasing temperature and prolonged time after thermal hydrolysis treatment, while Cr, Ni, Cu, Cd and Pb in residue fraction increased significantly after treatment. The contents of bioavailable heavy metals were strongly correlated to indicators such as ammonia-N, SCOD, soluble protein, and VS. The ecological risk of individual heavy metal was closely related to its migration and transformation, and the risk index of total potential ecological risk of heavy metals in sludge was significantly reduced after thermal hydrolysis treatment.

Based on the thinking of the traditional refining and chemical integration, how to use the temperature to strengthen the refining and chemical process was analyzed in a vertical series mode, and the refining and chemical technologies were summarized in a horizontal parallel mindset. Therein, the way of energy supplying by electricity was used to reconstruct the traditional steam cracking technology so that it could achieve a new technical route and the innovative development space for refining and chemical integration under re-electrification. In the meantime, by replacing the fuel furnace with electric energy, the direct steam cracker electrification technology and dry reforming technology could make not only the traditional oil refinery and olefin plant to realize energy conservation, emission reduction and low-carbon transformation, but also the dry gas obtained by the way of electric energy supplying to produce syngas and hydrogen, which could be used in the reduction iron by hydrogen metallurgy to help China’s steel industry decarbonizing, in the methanol production to promote China’s CCUS developing, and also in the green hydrogen of auto industry to support the China’s dual-carbon target achieving.