Fluidization technology has passed nearly 80 years since it was successfully applied commercially to the petroleum catalytic cracking process in the 1940s. In China, fluidization technology has experienced periods of fast and steady development track along with the reform and opening of the country after a difficult initial R&D stage. This paper highlights the development of fluidization technology in China over the past several decades. After reviewing the origination and progress of fluidization research in the world, we devote the limited pages to significant contributions that Chinese scholars have made to the development of fluidization theory and technology in the world and China over the years, especially the achievements in industrializing fluidization technology, based on the author's best understanding and knowledge. Finally, we provide a brief perspective on the future research and development direction of fluidization technology in China.

In recent years, adsorption and separation materials with a flexible three-dimensional framework have attracted significant interest from researchers. Their unique dynamic adsorption behavior and chemically rich structural framework give them properties utterly different from those of traditional rigid adsorption materials. These unique flexible adsorption materials have shown great potential in adsorption and separation, and environmental purification and sensing. However, the development of this field has needed to be faster due to the lack of in-depth understanding of flexible adsorption phenomena and corresponding theoretical research methods by researchers. In this paper, based on the latest research progress in the definition, theoretical development, and classification of flexible adsorption, we provided an in-depth analysis of its application examples in the removal of pollutants and separation of azeotropes and aim to provide the corresponding theoretical help for the development of this field. The article also pointed out the direction and prospect of industrialization of flexible adsorption materials, and efforts should be made to explore the application prospect of flexible adsorption materials for large-scale and high-efficiency treatment of liquid-phase (gas-phase) environmental pollutants with high (low) concentrations so as to promote the industrialization of flexible adsorption materials.

As one of the important technologies to control greenhouse gas emissions, Carbon Capture and Storage technology has attracted more and more attention. Compared with traditional production systems, carbon dioxide emission sources and sequestration sinks in Carbon Capture and Storage systems are often far away from each other. Transportation by pipeline is currently the most economical way to transport carbon dioxide over long distances on a large scale. In this paper, the mathematical model of the pipeline system for carbon capture was established. For the single-period problem, in order to minimize the total project cost of the pipeline system, the optimal pipe network structures of the pipeline system with and without intermediate nodes were obtained under different carbon capture and storage requirements, and the influence of variation of the carbon emissions on the pipeline system was analyzed as well. For the multi-period problem, considering in a long period of project planning, under the two scenarios of maximum total carbon capture and storage requirement and minimum total project cost of the pipeline system, the impacts of the carbon emissions of sources, injection rates and storage capacities of sinks on the optimal pipe network structures were explored.

The corrosion problem caused by ammonium salts deposition in the top circulation system of crude oil distillation column is one of the problems that lead to local failure and leakage of equipment and pipelines. To understand the mechanism of corrosion, the simulation method of Ab initio molecular dynamics (AIMD) and the experimental method of in situ electrochemical measurements were conducted to explore the hygroscopic properties of ammonium salts and the corrosion evolution for SAE 1020 carbon steel at different temperatures and concentrations. The results of electrochemical impedance spectroscopy and surface characterization reflected that the interfacial process of corrosion was a dynamic mass transfer process under the influence of corrosion product growth, film formation and damage behavior, combined with linear polarization resistance and weight loss tests, and the change of corrosion rate was determined by the mass transfer effect of the product and the electrode reaction process. The results of AIMD demonstrated that the charge state in the system under the action of water molecules was altered, including ionization, hydrolysis, proton transfer chain, etc., which may be an important cause of corrosion.

The refinery short-cut column model plays an important role in the practical application of refinery production scheduling. As the traditional short-cut model does not conform to the actual assumptions, it cannot reflect the true nonlinear property of the product distillation curve. In this study, a refinery short-cut column model based on separation factor was developed. The separation process of the oil refining column was simplified as continuous separation unit by using the relationship between the degree of component separation and the boiling point, and the nonlinear degree of the model was reasonably improved. The model could satisfy the two calculation modes of given cutting point or yield. Based on parameters such as cutting temperature or yield and separation factor, the secant method was used to solve iteratively, which could better simulate the incomplete separation process near the cutting point of the product. The model was verified by an example of the atmospheric and vacuum process. The results showed that the relative deviation between the calculated values of main process indexes and the actual values was within 5%, which proved that the developed model could effectively simulate the refinery column production process.

The study of mass transfer behaviors between bubble phase and emulsion phase is plays an important role in the design and regulation of fluidized bed reactor. The interaction between bubbles increases the complexity of mass transfer process. In this paper, computational fluid dynamics-discrete element method (CFD-DEM) was used to simulate the mass transfer process of two vertically distributed bubbles in a three-dimensional injected bubbling fluidized bed. On the basis of the independent determination method of mass transfer coefficients by convection and diffusion, the evolution of different mass transfer mechanisms with mutual interaction between bubbles was analyzed and the difference of mass transfer processes of two-bubbles and single-bubble was compared. The results showed that compared with the single bubble, the lower bubbles were axially stretched due to the existence of the upper bubbles. The volume of lower bubbles was reduced and the bubble rising velocity was increased. For the mass transfer process, the release of gas species from the upper bubbles increased the resistance of the diffusion-induced mass transfer of the lower bubbles and the reverse convective mass transfer was present. The interval of injection time further affected the mass transfer process. The complex mass transfer process of bubbles depended on many factors including the gas flow characteristics, the evolution of bubble shape and the concentration interference between bubbles.

The micro particle image velocimetry (micro-PIV) technique was used to study the flow field characteristics of single and parallel double micro-cylindrical bypass flow in microchannels. The effect of Re on the velocity field, vortex intensity, vortex angle and vortex dimensionless length was analyzed by observing the single and parallel double micro-cylindrical bypass flow fields at different Reynolds numbers (Re). The experimental study revealed that the vortex formation and shedding of cylindrical winding flow at the micro-nano scale had a certain hysteresis compared with that of cylindrical winding flow at the macroscopic scale. The hysteresis of parallel double micro-cylinders was larger than that of single micro-cylinders. The length and width of the vortex increase with increasing Re, and the vortex volume band extended further downstream of the microcylinder. The vortex angle and the dimensionless length of the vortex also increased with Re. The parallel double microcylinder I vortex structure was deformed and showed a drum shape. Affected by the mainstream region, the vortex structure was squeezed and showed a band vortex, while the position of the focal point was shifted toward the direction of the horizontal line of the center of the two cylinders. With the increasing of Re, the dimensionless vortex length and vortex angle showed an overall increasing trend.

Hydrofluoric acid (HF) alkylation is the main process of alkylbenzene production, and acid-hydrocarbon separator is one of the key equipment in the process. Due to the high corrosivity and high hazard of HF catalyst, the separation method of large tank sedimentation is still in use. As a result, the retention time of reaction effluents is long and the amount of HF reserves is large, which brings great risks to alkyl benzene units. There have been few researches on the separation of the system (both at home and abroad) due to the particularity of the medium. In this paper, a coalescence separator suitable for rapid separation of HF and alkylated oil was developed and pilot test was carried out. The acid content of oil phase outlet (≤0.2%) and the circulating acid concentration of acid phase outlet (≥98.5%) met the technological criterion. Moreover, the acid-hydrocarbon separation rate increased about 2 times, and the volume of separator and the amount of HF reserves shrank by more than 2/3. In view of the emulsification phenomenon of the reaction system, the emulsion yield and reduction rate were measured and calculated in the test, and the multi-layer boundary distribution of acid, hydrocarbon and emulsion layer in the separator was elucidated, which provides a good guide for the upgrading and transformation of HF catalytic process.

In order to promote the formation of HCFC-141b hydrate under static conditions, the condensate surfactant OP-13 of octylphenol and ethylene oxide was chosen to study its effect on the formation of HCFC-141b hydrate. Stable HCFC-141b-water emulsion can be prepared by adding OP-13. The experimental results showed that adding of OP-13 can significantly shorten the induction time of HCFC-141b hydrate formation. When OP-13 with mass fraction of 1% was added, the average induction time of HCFC-141b hydrate formation was the shortest, about 96min. The mass fraction of OP-13 affected the cold storage capacity of HCFC-141b hydrate. When 0.5% or 1% OP-13 was added, the cold storage capacity of HCFC-141b hydrate was bigger, which was 247.57kJ/kg and 248.42kJ/kg, respectively. Considering the induction time and cold storage capacity of hydrate formation, 1% OP-13 was the best addition. The experimental results also showed that HCFC-141b hydrate nucleation was random, and the addition of OP-13 stabilized hydrate nucleation. The surfactant OP-13 promoted hydrate formation mainly due to its micelles. Hydrate can form rapidly and stably due to the "memory" effect during hydrate formation/dissociation.

The oxygen mass transfer resistance in the cathode catalyst layer of proton exchange membrane fuel cell (PEMFC) is the main bottleneck limiting the polarization performance of membrane electrode with low Pt at high current densities. To reduce the oxygen mass transfer resistance of the cathode catalyst layers is of highly significance for the improvement of PEMFC performance and accelerating its commercial applications. In the paper, the sources and contributions of oxygen mass transfer resistance in catalyst layers have been analyzed. It is pointed out that the local oxygen mass transfer resistance is primarily caused by the resistance across the three-phase contact interface among the gas phase, ionomer, and Pt nanoparticles. The influences on the oxygen mass transfer resistance, especially the local one have been expounded from four aspects of Pt nanoparticle, ionomer, carbon support and the water formed, respectively. The methods of reducing oxygen mass transfer resistance have also been summarized. Finally, the design of cathode catalyst layers with low Pt for PEMFC is prospected. It is proposed that constructing suitable support pore structure, rationalizing the Pt particle distributions both inside and outside of the pores, controlling ionomer thickness and its distribution, as well as strengthening water transfer, could help to reduce the oxygen mass transfer resistance and thus to promote the cell power outputs at high current densities.

Chemical upcycling soapstock into biofuels is of great significance to reduce environmental pollution and achieve carbon neutrality. Biofuels were produced from soapstock by pyrolysis and subsequent catalytic vapor-phase hydrotreating in a pressurized two-stage fixed bed reactor. The effects of soapstock pyrolysis, non-catalytic and catalytic vapor-phase hydrotreating on the production of n-alkanes were explored. The reaction mechanism of n-alkanes obtained from the pyrolysis and catalytic vapor-phase hydrotreating of soapstock was proposed. To maximize the production of n-alkanes, the process parameters including pyrolysis temperature and hydrogenation temperature were optimized. Experimental results indicated that the primary intermediates of pyrolysis were completely deoxygenated and hydrogenated with Ni/Al₂O₃-SiO₂ catalyst, and the relative content of C₅—C₁₇n-alkanes increased from 15.8% to 97.3%, compared with that of the non-catalytic. The yield of n-alkanes initially increased and then decreased with increase of pyrolysis temperature, and the highest yield was observed at 550℃. The yield of n-alkanes gradually decreased with increase of hydrogenation temperature, and the highest yield was observed at 300℃.

The purified and active CaSO₄ was derived from flue gas desulfurization slag using improved purification technology and relevant parameters, which was further utilized as the template to prepare CuFe₂O₄ modified CaSO₄ mixed oxygen carrier (OC) with special "core-shell" structure via sol-gel combustion synthesis method. Effects of reduction temperature and cycle numbers on the reaction of CaSO₄-CuFe₂O₄ mixed OC with coal were studied on the fixed bed reactor. Meanwhile, gaseous sulfur species emitted from different CaSO₄ side reactions and their interaction with the introduced CuFe₂O₄ were further investigated. The results indicated that during reaction of the CaSO₄-CuFe₂O₄ mixed OC with coal, the reduced CuFe₂O₄ products as Cu and FeO regained the unutilized lattice oxygen included in the CaSO₄via the solid eutectics between the unreacted CaSO₄ and reduced CaS to realize their in situ oxidization, which not only enhanced the reactivity of the CaSO₄-CuFe₂O₄ mixed OC and promoted coal conversion, but also benefited the directional transfer of the oxygen involved in the unreacted CaSO₄ to reach cascade utilization of the oxygen involved in the mixed OC. Furthermore, through comprehensive consideration of carbon conversion for coal and gaseous sulfur release from CaSO₄, optimized reaction condition was determined as 900℃. Finally, after reduction and oxidation cyclic experiments, CaSO₄-CuFe₂O₄ OC was found to incompletely inhibit the CaSO₄ side reactions coupled with partly sintering of the reduced OC, which caused the cyclic reactivity of the modified OC to decay.

In the face of the growing domestic hot water and electric energy demand of residents, the application of PV/T technology can reduce the energy consumption during building operation. In this paper, a solar PV/T photovoltaic energy storage direct drive CHP system was introduced. In order to reduce energy loss during system operation, direct current compressor and energy storage battery were used, and the operation performance of the system was tested in Lanzhou. The results showed that the PV panel temperature of the PV/T system was on average 12.26℃ lower than that of the traditional PV module, and the average power generation efficiency was relatively increased by 8.1%. In the process of heating water from 24.4—27.2℃ to 50.1—50.7℃, the average COP could reach 5.48, which was 82.1% to 106.8% higher than that of the traditional air source heat pump water heater. The average heat collection efficiency and comprehensive efficiency were 37.30% and 71.24% respectively, the power generation and consumption of the PV/T system were 3.33kWh and 1.69kWh respectively, and the power generation was 5.7% higher than that of PV system. In general, solar PV/T photovoltaic energy storage direct drive CHP system could decrease energy consumption of the construction sector, improved the power generation efficiency and comprehensive efficiency of the PV/T system, and realized off grid operation under sunny conditions.

Platinum based catalysts play an important role in many important liquid phase hydrogenation reactions. It is of great significance to develop catalysts with controllable size, crystal shape and morphology so as to provide high platinum utilization rate and good activity. The latest research progress of platinum based catalysts is systematically reviewed in this paper, including the synthesis methods of different platinum nanocatalysts, the types of reducing agents, and the influence of important factors (including particle size, morphology, composition and carrier) on the catalytic activity and selectivity of platinum-based catalysts. Despite of their high catalytic efficiency, Platinum-based catalytic materials are still very expensive, so further exploring the hydrogenation mechanism of platinum-based catalysts, increasing the catalyst life while reducing the cost and realizing their controllable preparation are still the key research directions in the future.

High value-added products such as aromatic methanol, formaldehyde and formic acid that are derived from methyl aromatic hydrocarbons have been always in short supply worldwide. Because of its high conversion rate, low cost, good safety and other advantages, liquid phase selective catalytic oxidation is the main production method of methyl aromatic hydrocarbon derivatives in industry at present, and the high performance catalyst is one of the key factors. Based on the summary of the catalytic oxidation mechanism of methyl aromatic hydrocarbons, the applications of metal salt catalysts, metal complex catalysts, metal-organic framework (MOF) catalysts, metal oxide catalysts and other catalysts are reviewed in this paper. In order to improve the activity and stability of catalysts and reduce the preparation cost, researchers improves different kinds of catalysts, and find that the improvement of the performance of metal salt and metal complex catalysts lies in the development of corresponding support, while that of the MOFs catalyst should develop high activity Co and Mn metal MOFs catalysts. Besides, the development of metal oxide catalyst should optimize the existing preparation process. Finally, the improvement measures and future development directions of catalysts for liquid phase catalytic oxidation of methyl aromatic hydrocarbon are proposed.

With the merits of green, effective, safe and on site, hydrogen peroxide production via electrocatalytic two-electron oxygen reduction process is considered as an alternative to the traditional high pollution and energy intensive anthraquinone method. Benefitting from the virtues of high atom utilization, homogeneous active sites and high activity, single atom catalysts for two-electron oxygen reduction show great potential in hydrogen peroxide production. This paper focuses on the progress of single atom catalysts including both noble metal and non-precious metal in electrocatalytic oxygen reduction to hydrogen peroxide. Both experimental results and theoretical calculations are emphasized to reveal the relations between electronic structure and catalytic performance. Strategies to enhance the two-electron catalytic performance including altering of central metal atoms, regulation of coordinated atoms and local environment are also summarized. This paper aims to provide ideas and reference for the design of catalysts with high activity and selectivity towards hydrogen peroxide production. Opportunities and challenges of single atom catalysts for electrocatalytic oxygen reduction to hydrogen peroxide are prospected. Characterization of active sites, stability and preparation method for single atom catalysts are urgently needed to be improved to promote their development in hydrogen peroxide production via electrocatalytic oxygen reduction.

The emission of nitrogen oxides (NO _x ) has seriously harmed the ecological environment and human health, and they are mainly from fixed source of flue gas emissions and mobile source of exhaust emissions. In recent years, hydrogen selective catalytic reduction (H₂-SCR) to modify platinum based catalysts to control mobile source NO _x has attracted extensive attention. Because different modification methods can promote the electron migration between platinum and the support to form bifunctional reaction mechanism acid sites, Therefore, it is of far-reaching significance to develop efficient mobile source denitration catalysts by deeply understanding the NO _x catalytic reaction mechanism of platinum based H₂-SCR catalysts. In this paper, the types of platinum based H₂-SCR denitration catalysts are reviewed, and the mechanisms of H₂/NO adsorption, NO oxidation reduction, and dual function reaction on their surfaces are described. The strengthening methods to improve the stability, sulfur resistance and selectivity of platinum based H₂-SCR catalysts are summarized. Further investigations of the multivalence and electron mobility of highly efficient metal oxide and molecular sieve-loaded Pt-based H₂-SCR catalysts and the mechanism of NO, H₂, and O₂ on the catalyst surface, as well as the reduction of Pt loading for cost reduction, are also foreseen.

Selective catalytic reduction of ammonia (NH₃-SCR) is recognized as one of the most effective technologies for NO _x elimination, and efficient and stable catalysts are the core of NH₃-SCR technology. Cu-based zeolite catalysts, especially Cu-SSZ-13, have attracted extensive attention and research. However, there are still some problems, such as low high temperature activity, insufficient N₂ selectivity and poor sulfur resistance. In order to further improve the denitrification performance of Cu-SSZ-13 zeolite catalysts, transition metal modification can be applied. In this paper, the research progress of Cu-SSZ-13 zeolite catalyst modified by transition metals is reviewed, and the preparation methods of Fe-modified Cu-SSZ-13 zeolite are summarized. The ion exchange method, impregnation method and one-step hydrothermal synthesis method are introduced respectively. The differences and reasons of denitrification performance of Cu-SSZ-13 zeolite modified by different transition metals (Fe, Mn, Nb, Co, Ni, Ti, Zn) are discussed. Finally, the research emphasis and development prospect of Cu-SSZ-13 zeolite catalysts modified by transition metals are prospected, and it concludes that the form, location and synergistic mechanism of transition metals in Cu-SSZ-13 zeolite need to be further studied.

Nano zero-valent iron (nZVI) has been considered to be one of the potential materials, however, its high activity makes it easy to corrosion in air and water and the formed passivation layer covering the surface of particle leads to reduction of the active sites. The researches indicate that the problem of oxidation, passivation and agglomeration of nZVI can be reduced by the modification method. This paper mainly introduces the coating, loading, bimetallic and sulphurization four modification methods, and the enhancement mechanism of modified nZVI is discussed. The application problem of modified nZVI is indicated and relevant suggestions are given for the problems. The nZVI composites prepared by various modification methods can not only reduce the agglomeration and improve the treatment effect of target pollutants, but also can solve the potential problems of biotoxicity. It also suggestes that one of the future research points is the size of nanoparticles and the stability of modified materials.

Ethylene vinyl acetate copolymer (EVA) is one of the most widely used polymer pour point depressants commercially. It can disperse wax crystals by changing the crystallization process of wax crystals, effectively inhibit the formation of three-dimensional network structure of wax crystals, and improve the low-temperature fluidity of wax oil. Therefore, the research on the application of EVA pour point depressant in the field of crude oil pour point depressant has far-reaching significance. This paper summarized the research and application progress of EVA and its modified polymer in improving the low-temperature fluidity of waxy crude oil in recent years, introduced EVA pour point depressant and its effect after chemical, nano hybrid and synergistic modification, and expounded the pour point depressant mechanism and influencing factors. Compared with the traditional EVA pour point depressant, the pour point depressant after chemical modification, nano hybrid and cooperative modification can further change the morphology and structure of wax crystals and disperse wax crystals, thus significantly improving the pour point and viscosity reduction effect of crude oil. With the rise of long-distance pipeline transportation, repeated heating resistance and shear resistance were still important factors restricting the practical application of pour point depressants. Therefore, nano hybrid EVA was still the main research direction in the future.

In recent years, superhydrophobic coatings have drawn extensive attention in the anti-corrosion and anti-scaling fields. Taking the fundamentals of superhydrophobic surface as the starting point, this paper briefly introduced the Young model, Wenzel model and Cassie-Baxter model. Through comprehensive analysis, two essential requirements for the preparation of artificial superhydrophobic surfaces are obtained: nano-micro hierarchical structures and low surface energy. Then, the anti-corrosion and anti-scaling mechanisms of superhydrophobic coating are expounded in detail: ① the air layer trapped by the special nano-microstructures can effectively isolate the corrosive medium and affect the growth morphology of scaling; and ② the extremely low surface energy can greatly reduce the adhesion strength of corrosion and scaling ions. On this basis, the research progress of superhydrophobic coatings in anti-corrosion and anti-scaling fields in recent years is reviewed, and the principles and advantages of various research results are summarized. Moreover, the problems faced by superhydrophobic coatings in practical applications, including complex preparation methods, poor mechanical durability and insufficient chemical stability, are further pointed out. Finally, the future development direction of superhydrophobic coatings is prospected from the selection of coating materials and the improvement of the preparation process and the evaluation system, etc.

Graphene oxide/carbon nanotubes (GO/CNTs), as ideal carbon nanomaterials, have unique three-dimensional spatial structure and huge specific surface area, and are widely used in reinforcing polymer materials, which can improve the physical mechanical properties and stability of composite materials, and endow the composites with excellent thermal conductivity, electrical conductivity and dynamic mechanics, etc. In this paper, the preparation methods commonly used for the preparation of GO/CNTs bases are introduced, and the microscopic morphology, advantages and disadvantages of the composites prepared by the casting/coating method, the vacuum filtration method and the blending method are compared. The relationship between structural control and the properties of GO/CNTs-based composites is discussed. The modification of GO and CNTs, and the compatibility of GO/CNTs doping with polymer materials are introduced in detail. And its application in epoxy resin, rubber and biodegradable polymer is analyzed to explore the effect of GO/CNTs on the physical mechanical properties and functionality of composites. Finally, the technical advantages and current problems of GO/CNTs modified polymer materials are summarized, and the future development direction is prospected in order to provide a reference for the preparation of high value-added products from GO/CNTs modified epoxy resin, rubber and other polymer materials.

With the increasing demand for nuclear energy, it is of great significance to extract uranium from seawater as a supplement or substitute for traditional uranium resources. Owing to the high specific surface area and tunable pore structure, metal-organic frameworks (MOFs) have attracted extensive attention in academia as a novel adsorbent for uranium capture. Regarding the water instability, low selectivity and difficult separation of MOFs from seawater after uranium capture, these issues can be addressed by surface modification and composite with heterogeneous materials. This paper briefly introduced the structural advantages of MOFs materials for uranium extraction in water, analyzed the influence factors of water stability, listed the properties of three representative types of water-stable MOFs materials, summarized the performance of these MOFs applied to extract uranium from seawater and investigated the mechanism. Meanwhile, the uranium extraction performance by pristine MOFs, surface-functionalized MOFs and MOFs composites are compared. Based on the structural characteristics of MOFs and the adsorption mechanism of uranyl ions, it is concluded that the future development direction of uranium-removing MOFs adsorbents is to improve water stability, perform surface functionalization of MOFs and expand multiple material composite methods.

Supported metal nanoparticles have been widely applied in catalytic processes related to energy conversion and storage. However, the size and distribution of metal nanoparticles prepared by impregnation and deposition are difficult to control. The metal nanoparticles catalysts are often deactivated due to sintering, carbon deposition and other problems in operation. The exsolution strategy is expected to provide a feasible way to solve the above problems. The exsolved metal nanoparticles are embedded and evenly distributed on the surface of the oxide matrix, which can provide a strong metal-support interaction and effectively alleviate sintering and coking. Based on the metal exsolution of perovskites, this paper summarizes the characteristics and formation process of exsolved metal nanoparticles and introduced the driving forces of oxygen vacancy, phase transition and Gibbs free energy in the exsolution process. Then, the effective methods to control exsolution are proposed from the characteristics of the matrix and the reduction conditions. Finally, the application progress of exsolution strategy is discussed. However, the exsolution mechanism and properties regulation of metal nanoparticles needed to be further studied by combining in situ characterization technology and theoretical calculation. This paper provides an important reference for optimizing the surface properties of metal nanoparticles and developing high-performance catalysts.

The development of highly efficient and low-cost cathode catalysts for microbial fuel cell (MFC) cathode catalyst is the most urgently needed. In this study, the bimetallic blade structure Co/Zn-ZIF precursor material was prepared by combining the ZIF-8 and ZIF-67 with similar crystal structure. The Co₃O₄/ZnO(x)-ZIF cathode catalyst was prepared by using the Co/Zn-ZIF precursor as template, and N and C sources. The effects of Co content (x) on catalyst structure, oxygen reduction (ORR) performance and power generation performance of MFC were studied. The results showed that among the as prepared Co₃O₄/ZnO(x)-ZIF catalysts, Co₃O₄/ZnO(2)-ZIF possessed the best performance. The MFC output voltage decreased in the order of Pt/C (0.58V)>Co₃O₄/ZnO(2)-ZIF (0.52V)>Co₃O₄/ZnO(3)-ZIF (0.43V)>Co₃O₄/ZnO(1)-ZIF (0.39V). The maximum power density and COD removal rate of MFC using Co₃O₄/ZnO(2)-ZIF as cathode catalyst were 741.1mW/m² and 96.1%, respectively, which were close to those of commercial Pt/C (848.1mW/m² and 96.9%). This is attributed to its high pyridine N content and suitable pore structure and Co/Zn ratio. In addition, Co₃O₄/ZnO(2)-ZIF followed a 4-electron transfer path and exhibited no significant decrease in electrical performance within 30 days operation, showing excellent stability.

The hierarchical porous carbons were prepared from rice husk bio-oil as carbon precursor by using magnesium chloride (MgCl₂) as a template agent and potassium oxalate (K₂C₂O₄) as activator. The effect of process parameters on the physicochemical properties and electrochemical properties of porous carbon was investigated. It was shown that K₂C₂O₄ as an activator could etch the carbon skeleton and greatly increase the pore structure of carbon. MgCl₂ template could improve the activation effect and increase the mesopore ratio. The BOC-3 prepared under the optimal activation conditions had a three-dimensional foam structure, high specific surface area (1961.1m²/g), high mesoporosity (47.25%) and high oxygen content (15.0%). Benefiting from the multiple synergistic effects of these properties, BOC-3 has a mass specific capacitance of 280F/g, and a specific capacitance retention rate of 94.8% after 5000 cycles of charging and discharging. BOC-3 had excellent rate performance and cycle stability. This study revealed that the combination of K₂C₂O₄ activator and MgCl₂ template could be used as an efficient route to fabricate hierarchical porous carbons for high-performance supercapacitors from bio-oil, which was conducive to the high value utilization of bio oil.

Lignin/polyaniline(Lig/PANI) composite material was prepared by chemical polymerization with polyaniline(PANI) and lignosulfonate(Lig). The morphology, structure and properties of the materials were characterized by scanning electron microscopy, transmission electron microscopy and infrared spectroscopy. The adsorption properties of composite materials on Congo red was studied, and the effects of the amounts of adsorbent, initial concentration of dye, and adsorption time on the adsorption properties were investigated. The results showed that under the dosage of 20mg adsorbent and the initial concentration of 350mg/L, Congo red had the best adsorption effect within 200min and the highest adsorption capacity was 431.17mg/g. The adsorption process followed the Freundlich adsorption model and the quasi-second-order adsorption dynamic model, in which chemisorption was dominant and belonged to multi-molecular layer adsorption. The adsorption mechanism of Congo red mainly included electrostatic attraction, pore adsorption and electron transfer during the adsorption process. The internal diffusion model indicated that the internal diffusion was not the only factor controlling the adsorption rate, and the whole process of adsorption was spontaneous and entropic.

Great attention has been attracted by researchers due to the stable fluorescence properties, adjustable structure and low cost for organic luminescent molecules. In order to obtain functional organic luminescent molecule with excellent properties, a multifunctional organic luminescent molecule APAD with A-D-A type was synthesized by Suzuki reaction by adjusting the structure of molecule. The structure, energy level and potential difference distribution were determined by theoretical calculation, indicating the exist of intramolecular charge transfer characteristic in the molecule. The energy level was further analyzed by electrochemical analysis test. In addition, the aggregated luminescence study showed that APAD displayed typical aggregation induced emission effect. Finally, the applications for molecule APAD were studied utilizing its molecular luminescence characteristics. It was found that APAD can be used as an organic fluorescent probe to detect the harmful substance hydrazine hydrate in real-time detection with high selectivity and anti-interference, and the limit of detection is as low as 3.2×10^-7mol/L was calculated. Additionally, it was also used as a fluorescent thermometer due to its temperature dependence of fluorescent characteristics.

Compared with polymer gels, small organic molecule-based gels possess easy modification, have better stimuli response, and show great application potential in many fields. In this work, gallic acid and mono-carboxy tetraphenylene were used as the starting materials to synthesize a gelator G1 with both aggregation-induced emission property and reduction responsiveness. The gelator G1 can self-assemble into gels in cyclohexane and dimethyl sulfoxide (DMSO), and the critical gelation concentrations were 5.6mg/mL and 16.7mg/mL, respectively. The results of UV-vis spectroscopy, fluorescence spectroscopy, infrared spectroscopy, temperature-dependent NMR study and XRD study indicated that π-π stacking and hydrogen bonding were the main driving forces for the formation of the gel. In addition, the results of the contact angle study indicated that the contact angle of the xerogel films derived from the DMSO gels was as high as 137°, suggesting strong hydrophobicity of the xerogel films, which can be potentially applied in the field of stimuli-responsive fluorescent hydrophobic materials.

Using zinc oxide quantum dots (ZnO QDs) as fluorescent pigment, water as solvent and polyethylene glycol (PEG) as film forming material, ZnO QDs water-based inkjet fluorescent ink was synthesized. By analyzing ink viscosity, surface tension, printability parameter Z value and fluorescence intensity, the effect of PEG concentration on ink rheology and fluorescence properties was explored, and the optimal ink formulation was obtained. The results showed that the ink fluorescence intensity was the best when the amount of ZnO QDs was 30mg/mL and the volume fraction of PEG aqueous solution was 40%. The viscosity was 7.56mPa·s, the surface tension was 51.95mN/m and the Z value was 6.77, which met the quality index of inkjet printing ink. The contact angle was 58.71°, there was no coffee ring phenomenon, and the adhesion property was good. The prepared ink can combine with two-dimensional code technology, fluorescence quenching scheme and combined printing method to achieve multiple anti-counterfeiting effects, and thus had practical application value.

Gemini ionic liquid, 1,1'-(1,3-trimethylene)-bis-3-methylimidazolium dibromide [C₃(MIM)₂Br₂], was synthesized using 1-methylimidazole and 1,3-dibromopropane as raw materials. A series of deep eutectic solvents were prepared by mixing C₃(MIM)₂Br₂ and ethylene glycol with various molar ratios. Melting points of all deep eutectic solvents were lower than -90℃, much lower than those of C₃(MIM)₂Br₂ and ethylene glycol, and increased with the increase of ethylene glycol composition. The thermodynamic properties of the deep eutectic solvents, including density, viscosity, electrical conductivity and specific heat capacity, were respectively determined at temperature range of 288.15K to 323.15K. The results showed that the density and viscosity decreased with increasing temperature, whereas the electrical conductivity and specific heat capacity increased. With the increase of the molar ratio of ethylene glycol in the deep eutectic solvent, the density and viscosity decreased, while the electrical conductivity and specific heat capacity increased. The correlation coefficients of the linear equations of density and specific heat capacity with temperature were greater than 0.99. VFT equation was employed to correlate viscosity and conductivity data with temperature, and the correlation coefficients of the corresponding empirical equations were all more than 0.999.

Using polyaspartic acid (PASP) and polyacrylamide (PAM) as raw materials, magnetic PASP/PAM semi-interpenetrating (semi-IPN) hydrogels loaded with nano Fe₃O₄ particles were prepared by in-situ coprecipitation and semi-interpenetrating technology. The hydrogels were characterized by FTIR, TG, SEM, TEM and EDS. The magnetic properties, swelling properties and temperature sensitivity of the hydrogels were tested. The results showed that the prepared magnetic hydrogel had excellent thermal stability, and the nano Fe₃O₄ particles were spherical with a particle size of about 18nm and evenly dispersed. The hysteresis loop was “S” shaped, the maximum saturated magnetic intensity was 0.35emu/g, and it had superparamagnetic. The magnetic response time showed that the appropriate concentration of Fe₃O₄ was 1.0mol/L. When the concentration of nano Fe₃O₄ was 1.5mol/L and 0.5mol/L, the equilibrium swelling rate was 38g/g and 47g/g, respectively, and when the temperature was lower than 45℃, the swelling rate of hydrogels showed temperature sensitive and positive characteristics.

A water-soluble alkali lignin (AL) extracted from pine wood was used as raw material to prepared amphoteric lignin (AML-45) which used (3-chloro-2-hydroxypropyl)trimethylammonium chloride solution to chemical modify the AL by quaternization. AML-45 was activated in 8g/L NaOH, 12g/L urea and -10℃, then in alkaline medium activated AML-45 and polyethylene glycol diglycidyl ether were co-polymerized to prepare lignin-based pH-responsive hydrogel. The structures of AML-45 and lignin-based hydrogel were characterized by FTIR spectroscopy, DLS measurement. Scanning Electron Microscope was used to discover hydrogel's morphological characteristics. The swelling behavior of the hydrogel at different pH PBS-buffered solution was tracked. These results showed that the hydrogel was highly pH-responsive to a range of pH 2—7.4, with the swelling rate reaching minimum of 260%(pH=4) and maximum of 330% (pH=7.4). In addition, the swelling rate of hydrogel related to the lignin concentration, amount of cross-linker polyethylene glycol diglycidyl ether and 5-fluorouracil was used as model drug to explore its drug release behavior in buffer media in the acidic range (pH=2—7.4). The cumulative drug release from the loaded hydrogel in buffer solution (pH=7.4) was up to 78% within 30h which was higher than the cumulative drug release of 62% (pH=4) and 69% in (pH=2) in acidic buffer environment. The hydrogel had significantly drug retarded effect.

In order to study the self-healing behavior of asphalt under different crack damage and healing temperatures, a molecular model of asphalt was constructed by molecular dynamics (MD) method to simulate the self-healing behavior of 70^# matrix asphalt under the conditions of temperature 313—333K and crack width 10—50Å. The rationality of the asphalt molecular model was verified from the density of asphalt molecular model, radial distribution function, glass transition temperature, cohesive energy density and solubility parameters. The self-healing ability of asphalt molecular model was evaluated qualitatively (density and mean square displacement) and quantitatively (diffusion coefficient, cohesive energy density and free volume fraction). The results showed that when the self-healing temperature was 313—333K, the cohesive energy density of the healing models with different crack widths fluctuated in the range of 0.2%—3%, indicating that the self-healing of asphalt molecules was insensitive to the temperature change in this temperature range. When the crack width of asphalt molecular model was 30Å, the healing process of the model was obvious and the healing effect was also the best. It was recommended to use 30Å as the crack width of 70^# matrix asphalt healing model.

A method of molecularly imprinted solid phase extraction combined with high performance liquid chromatography (MISPE-HPLC) was developed for the determination of two triazine herbicide residues in tobacco leaves. An optimal functional monomer was firstly selected and then the optimum polymerization ratio of the template molecule (TER) to the functional monomer (AA) was determined by computer simulation technology. Based on the simulation results, the molecularly imprinted polymers of terbutylazine were prepared by precipitation polymerization. Comparing the infrared spectra of the computer-simulated complex with the experimentally prepared TER-MIPs, the analysis showed that the main absorbing groups of them had the same peak positions. The adsorption performances of MIPs to the template molecule and its structural analogs were investigated. It was found that MIPs had good specific adsorption capacities for TER and its structural analogs. TER-MIPs was used as a solid phase extraction filler to prepare a TER-MISPE column for pretreatment of spiked tobacco leaves and the samples were analyzed by HPLC. The results indicated that MISPE had better enrichment effect on terbutylazine and terbumeton. The average recoveries of the two triazine herbicides were between 84.29% and 96.64% and the relative standard deviations (RSD) were 1.19%—1.70% (n=3). The method can meet the requirements of simultaneous determination of terbutylazine and terbumeton triazine pesticide residues in tobacco leaves, providing support for the analysis and detection of triazine herbicides in tobacco leaves and crops with complex substrates.

Multi-enzyme co-immobilization systems, in which two or more enzymes are immobilized onto or into the same carrier, are based on enzyme cascade reactions. Due to their high atomic economy and sustainable utilization properties, such systems have become a research hotspot in various fields such as material science, life science, and biomedicine. Selecting suitable carrier materials is the most basic and important way to improve the catalytic efficiency of multi-enzyme co-immobilization system. In this paper, the cascade reaction consisted of glucose oxidase and horseradish peroxidase was used as the model reaction, and the current research progress of carriers for multi-enzyme co-immobilization was summarized from three different interaction forms between carriers and enzymes: random immobilization, partition immobilization and directional immobilization, respectively. Finally, in order to provide research ideas for more multi-enzyme co-immobilization systems, the limitations and challenges in this field were analyzed.

The online detection of glucose, a key substrate in the fermentation process, plays a key role in improving the fermentation efficiency and assessing the fermentation status in real-time. At present, traditional offline detection has problems such as complicated operation, large errors, and long lag time, which make it difficult to meet the requirements of concentration feedback control in the fermentation process. To address the problem of online accurate and wide range detection of glucose in the fermentation process, an adaptive Kalman filter high-precision detection method was proposed based on a homemade glucose enzyme biosensor. Firstly, a detection module was built, a concentration-response characteristic equation was established for calibration, and an automatic adjustment of the feed volume strategy was proposed to achieve high accuracy detection under a wide range of concentrations. The noise interference characteristics during the 10^-6 level current acquisition process were analyzed, and the moving average filtering algorithm was combined with the high concentration detection to further extract the effective signal under the noise by partitioning the segments. The experimental results showed that the error was less than 2% for a wide range of concentrations (1—180g/L), achieving high accuracy detection of glucose concentration in the fermentation process.

To establish a starch-based super absorbent polymer dust suppressant for industrial manufacture, a super absorbent resin dust suppressant was synthesized by mechanical activation one-step solid phase (MAMS) method, which took cassava starch, acrylic acid (AA) as raw materials, ammonium persulfate (AP) and sodium sulfite (SS) as initiator, and N, N'-methylene bisacrylamide as cross-linking agent. Process conditions for preparation of the materials were optimized by orthogonal test and single factor method according to viscosity and water absorption rate. FTIR, XRD, SEM and ¹³C NMR were used to test and characterize the materials. The results showed that the cassava starch was successfully grafted with acrylic acid to form a super-absorbent resin. This method could effectively destroy the starch granule structure and improve the reaction efficiency. The optimal conditions were as follows. The ball milling reaction time was 3h, the AA neutralization degree was 80%, the reaction temperature was 60℃, the AA/starch mole ratio was 1∶1, the initiator dosage was 0.9g, the cross-linking agent dosage was 0.05g and the rotation speed of the ball mill was 380r/min with 500mL ball mill medium. Under these conditions, the viscosity of the dust suppressant was 670mPa·s, the water absorption ratio was 116.21g/g, and the monomer conversion, grafting rate and grafting efficiency were 96.81%, 42.35% and 81.36% respectively. The dust samples sprayed with a concentration of 2% starch-based dust inhibitor could effectively prolong the water evaporation time, solidify the dust particles, enhance the damage resistance of the dust samples and improve the dust suppression effect. After evaporating for 7h, the moisture content of the dust samples was still as high as 6.85%, the particle size of the samples with more than 40 meshes was 38.93%, and the dust suppression rate under the wind speed of 9m/s reached 96.40%. The dust suppression effect was much better than those dust samples sprayed with water, proving the starch-based dust inhibitor to be a green and environmentally friendly one.

Potassium is the third element of plant growth, which plays a vital role in plant expansion, metabolism and growth. With 56% of China's arable land lacking potassium, the stable supply of potash is a matter of food security and agricultural security. China is the world’s largest consumer of potash, but its potash resources are seriously insufficient, and 50% of potash is imported. Due to the characteristics of non-renewable nature and unbalanced spatial distribution of potassium resources, it is of great significance to develop potassium resources reasonably under the increasing tense international situation. The present situation of global potash reserves and production status distribution are first introduced in this paper. There are some problems in the development and utilization of potassium salt in China, such as low storage-production ratio of potash, single product variety, and serious loss of potassium resources in the evaporation process of salt fields. This article reviews the related research on resource optimization and circular economy in the development of mineral resources at home and abroad, and puts forward suggestions on the efficient utilization and sustainable development of potassium resources in China, which provides a path for the high-quality development of potassium resources.

The photochemical products discharged by organic amines to the atmosphere include ammonia, aldehydes, amides, nitrosamines and so on. Nitrosamines have carcinogenicity and are considered as hazardous substances to health, as well as the health risk factors of air exhaust emissions from organic amine absorption process. Aiming at the CO₂ capture project of 2 million t/a in Shengli Power Plant, gaussian model was used to simulate the exhaust diffusion of emission absorber, and the emission concentration of nitrosamine with distance was studied. According to the American EPA health risk assessment method, the allowable atmospheric concentration of nitrosamines for children and adults was calculated, the risk level was assessed, and the safe protection distance of residents was determined. In view of the risk control, two methods were proposed to reduce the emission intensity of nitrosamine at the top of the tower and increase the emission height of tail gas. The research conclusion showed that when the emission intensity of nitrosamine at the top of the tower was reduced by 83%, or the emission height of tail gas was higher than 128m, the acceptable carcinogenic risk value reached 10^-6 level.

Cellulose-templated CaO-basted pellets were prepared by an extrusion-spheronization method. The effects of steam addition during calcination on the CO₂ capture capacity, mechanical properties, and microstructure of the modified sorbents were investigated based on a double fixed-bed reactor. The experimental results showed that the sorbent pellets formed stable pore structures under the combined effect of thermal sintering and atmosphere-induced sintering, ensuring that the CO₂ capture capacity and mechanical strength were maintained at a high level. The CO₂ uptake of the sorbent with 10% (mass ratio) cellulose and 5% (mass ratio) cement as well as 10% volume fraction steam reactivation was 0.32g/g after 20cycles, which was 132% and 60% higher than the raw sorbent (0.138g/g) and the modified sorbent (0.20g/g) without steam injection, respectively. Moreover, the average crushing strength of the pellets calcined with adding 10% volume fraction steam into the calcination atmosphere was 14.7N, which was enhanced by about 2.7 times that without steam. The strength was further increased to 20.5N after 50 cycles. Thus, steam injection during calcination demonstrated great potential in retaining CO₂ capture durability and improving the mechanical properties of the cellulose-templated sorbent.

In this study, tetramethylethylenediamine (TMEDA) was used as phase separating agent, four kinds of amines (ethanolamine, aminoethylethanolamine, triethylenetetramine and diethylenetriamine) that commonly used to capture CO₂ were mixed with TMEDA in a mass ratio of 1∶2. The solvent composed of TMEDA and AEEA could form a liquid-liquid phase separation after absorbing CO₂, and had the best CO₂ absorption characteristics, with absorption loading capacity of 1.620molCO₂/kg. The mixture of 1,8-diazabicyclo [5.4.0] undecano-7-en-imidazole ([DBU][Im]) ionic liquid and TMEDA-AEEA biphasic solvent was used to study the influence of [DBU][Im] on the absorption and phase separation characteristics. The material distribution of organic amine and CO₂ products in two phases were analyzed by ¹³C NMR spectrum. It was indicated the introduction of [DBU][Im] ionic liquids into TMEDA-AEEA biphasic solvent was helpful to increase the CO₂ absorption loading capacity. The [DBU][Im] ionic liquids, water and CO₂ reaction products were mainly distributed in the lower liquid phase, while TMEDA and a small amount of [DBU][Im] ionic liquids existed in the upper liquid phase. When the mass ratio of TMEDA, AEEA, water and [DBU][Im] ionic liquid was 10∶4∶5∶1, the absorption loading of the rich liquid phase of the absorbent was 49.6% higher than that of TMEDA-AEEA biphasic solvent.

To investigate the migration characteristics of heavy metals (Pb, As, Cu, Cr, Cd) and the influence of minerals on the heavy metal retention effect in the mixed combustion conditions, the combustion of sludge and coal slime alone and the co-combustion in multiple proportions were studied under different combustion conditions using an electric tube furnace and by means of ICP and XRD characterization analysis. The results showed that when sludge was burned alone, the volatilization rate of As increased with the increase of temperature, and the volatilization rates of Pb, Cu, Cd and Cr peaked at 700℃ and decreased with the increase of temperature at 700—900℃. For the combustion of coal slime, the volatilization rates of Pb and Cr gradually increased with the increase of temperature, the volatilization rate of Cu showed a trend of decreasing and then increasing with the increase of temperature and reached the lowest point at 700℃, while the volatilization rate of Cd was the opposite. For the coupled sludge-coal slurry combustion process, the retention rate of heavy metals in sludge-coal slurry at 5∶5 blending ratio was higher than that at 2∶8 and 8∶2 blending ratios, and the actual residual rates of Pb, As, Cu, Cr and Cd from mineral interactions in sludge-coal slurry at 900℃ combustion temperature at 5∶5 blending ratio increased by 148.9%, 5.8%, 28.6%, 112% and 75.7%, respectively, compared with the theoretical values. The retention of heavy metals in the mixed firing process was mainly influenced by the interaction between mineral components, in which, for single-component combustion conditions, SiO₂, Al₂O₃, and Fe₂O₃ were prone to react with heavy metals to form compounds that were difficult to volatilize and fused in the ash, while the mixed firing process could promote the decomposition of silica-aluminate and iron-containing compounds to form SiO₂ and other compounds in large quantities, which enhanced the heavy metal residual rate.

Liquid slag discharge is an important means to solve the problem of slagging and fouling in the combustion process of Zhundong coal. Blending low melting point fuel can effectively reduce the ash melting point of the mixed fuel, thereby improving the efficiency of liquid slag discharge. In this paper, high activated sludge and Zhundong coal were blended. The combustion characteristics and ash fusion behavior of the blends were studied by thermogravimetric analysis, ash melting point analysis, Fourier transform infrared spectroscopy and ash composition analysis. The results showed that the ignition temperature decreased significantly with the increase of sludge blending ratio, and the ignition performance and burnout performance of the mixture deteriorated rapidly when the sludge mass ratio exceeded 20%. The burnout temperature decreased first and then increased with the increase of sludge mixing ratio, and reached the lowest when the sludge mixing mass ratio was 10%. The results of infrared spectroscopy showed that the incorporation of sludge promoted the pyrolysis and combustion of active hydroxyl groups, aliphatic functional groups, oxygen-containing functional groups and aromatic functional groups in pulverized coal. The Fe₂O₃ in the sludge reacted with SiO₂ in the coal to form a low melting point eutectic, which made the mixed fuel be of a relatively low ash melting temperature. When the sludge blending ratio was 10%, the ash melting temperature of the mixture was 1080°C. Considering the stability of fuel combustion and the reduction of ash melting point, it was recommended that the optimal blending ratio of sludge and Zhundong coal is 1∶9.

Large production and difficult disposal of excess sludge has become a common problem faced by sewage treatment plants in China. In recent years, the use of ozone oxidation by-pass conditioning to achieve in-situ sludge reduction technology has attracted attention. A continuous SBR device was used to compare the differences in sludge reduction effect, effluent water quality and sludge characteristics between separate ozone oxidation (O₃) and Mn²⁺ catalytic ozone oxidation conditioning (O₃+Mn²⁺) to verify the practical application effect of Mn²⁺ catalyzed ozone oxidation. The results showed that the in-situ reduction effect of sludge in O₃+Mn²⁺ group was better than that of O₃ group, and the addition of Mn²⁺ had no obvious negative impact on the effluent quality of SBR process, and the removal efficiency of COD, NH₄⁺-N and TP after O₃+Mn²⁺ conditioning was slightly higher than that of O₃ group._{The apparent sludge yield coefficient Yobs of traditional activated sludge system was 0.32gMLSS/gCOD, group O3 decreased to 0.25gMLSS/gCOD and the group O3+Mn²⁺ decreased to 0.21gMLSS/gCOD, they decreased by 21.9% and 34.4%, respectively. From the sludge concentration (MLSS), the sludge reduction rate of group O3+Mn²⁺ was 2.6 times of group O3. At the same time, the flocculation, sedimentation and dehydration performance of activated sludge in the group O3+Mn²⁺ were all further improved.}

To solve the problem of high nitrate and ammonia nitrogen content and difficult removal in low carbon or inorganic industrial wastewater. The proposed sulfur (thiosulfate)-driven denitrification and anaerobic ammonium oxidation (Anammox) process was developed in two phases: first, the sulfur autotrophic short-cut denitrification (SASD) process was started up by gradually increasing the nitrate concentration in influent, and then, Anammox bacteria were loaded onto the filler, at (30±1)℃, a sulfur autotrophic short-cut denitrification coupled with anammox system (SASD-A) was constructed in 147 days. The interaction between SASD and Anammox process and denitrification contribution rate were clarified. Also, the effect mechanisms and microbial population response characteristics of different S/N (S₂O₃^2-∶NO₃^--N) ratios on the denitrification efficiency of the coupling process (SASD-A) were discussed. The results showed that the removal efficiencies of NH₄⁺-N, NO₃^--N and TN were 91.49%, 90.81% and 91.44% respectively, with the S/N of 3/1 in influent. The different S/N had a direct relationship with the relative abundance of functional bacterial genera. The dominant genera associated with denitrification function in the SASD-A system were Limnobacter (2.85%—4.71%), Denitratisoma (1.01%—1.99%), Candidatus_Brocadia (2.28%—18.81%), norank_f_Bacteroidetes_vadinHA17 (6.68%—10.81%) and norank_f_PHOS-HE36 (6.93%—11.47%) etc. Batch experiments showed that sulfur-oxidizing bacteria used reduced thiosulfate as an electron donor to convert it into S⁰ and sulfate, and nitrate was reduced to nitrite at the same time. And then it continued to be reduced to nitrogen gas taken ammonia as electron donor in the SASD-A system. Anammox process was responsible for the dominant nitrogen removal in the SASD-A system.

The effects of hydroxylamine (NH₂OH) on the activity and kinetic parameters of ammonia oxidizing bacteria (AOB) and the recovery of AOB activity after inhibition were investigated using SBR to treat synthetic domestic sewage. Results of batch test showed that when the concentration of NH₂OH was 4.5mg/L, the activity of AOB showed the highest level, the activity of nitrite oxidizing bacteria (NOB) decreased, and the oxidation rate of NO₂^--N (Q_{\mathrm{m}\mathrm{a}\mathrm{x}}^{\mathrm{N}\mathrm{O}\mathrm{B}}) decreased to 8.00mg/(L·h). The half-saturation constant of NO₂^--N (K_{\mathrm{N}{\mathrm{O}}_{\mathrm{2}}}^{\mathrm{N}\mathrm{O}\mathrm{B}}) increased to 7.77mg/L, indicating that the inhibition type of NH₂OH on NOB was mixed inhibition. In the long-term experiments, R1 and R2 were operated in anoxic/aerobic, and R3 was operated in aerobic/anoxic mode four times alternately per day. NH₂OH was added into R2 and R3 reactors and not in R1. The results showed that, there was no nitrite accumulation in R1. When the concentration of NH₂OH was 4.5mg/L in R2, the activity of AOB was (6.04±0.4)mgN/(gMLVSS·h) on the 6th day. When the concentration of NH₂OH was 10mg/L, the activities of AOB and NOB decreased to (0.16±0.1)mgN/(gMLVSS·h) and (0.15±0.1)mgN/(gMLVSS·h), respectively. The activities of AOB recovered on the 5th day under high strength aeration without adding NH₂OH. When the concentration of NH₂OH was 4.5mg/L in R3, the ratio of NO₂^--N/NH₄⁺-N in effluent was 1.2 on the 7th day. High-throughput sequencing of 16S rRNA showed that the relative abundance in R2 and R3 of AOB and NOB were 6.6%, 1.3%, and 3.0%, 1.9% when the concentration of NH₂OH was 4.5mg/L. Ellin6067 and Nitrosomonas belonged to AOB, and Unidentified Nitro spiraceae belonged to NOB.

Aiming at the problem of excessive heavy metals in the anaerobic digestion of pig manure, this paper constructed an anaerobic digestion system using pig manure/corn straw as raw material, and compounded three kinds of passivation agents of biochar, humic acid and fly ash. Then, the organic carbon fractional extraction method was used to analyze the changes of Cu and Zn species in the optimal passivation group and to explore the interaction mechanism between heavy metals and humic substances.The results showed that humic acid and fly ash had the optimal passivation effects for Cu and Zn, respectively, and the optimal compound ratios of humic acid∶fly ash∶biochar were B1 (7.5%∶7.5%∶7.5%) and B2 (5.0%∶7.5%∶7.5%). The ratio of humic acid (HA) to fulvic acid (FA) content in the system showed an increasing trend with anaerobic digestion. Before digestion, Cu and Zn in biogas residue humus of each treatment group mainly existed in the form of FA-Cu and FA-Zn, and after digestion, heavy metals were mainly combined with HA. The proportion of HA-Zn and HA-Cu in B1 and B2 was significantly higher than that in control group (CK), and the bioavailability in B1 and B2 was significantly lower than CK. Comparing the stable states of Cu and Zn, it was found that the amplitude of the stable state of Zn conversion was small, mainly because Zn was a heavy metal of amphotericity, which was more active and easy to bind with small molecule humus FA, while Cu mainly combined with macromolecular humus HA and the binding was relatively tight. In B1 and B2, the binding form of heavy metals and humus was more stable, so the compound passivator could further reduce the biological toxicity of heavy metals Cu and Zn in the anaerobic digestion. Infrared spectroscopic analysis found that passivators increased the aromaticity of the substrate, making it easier to bind to heavy metals, and aromatic, aliphatic compounds, proteins and polysaccharide compounds were the main heavy metal binding functional group.

Loofah sponge has a natural three-dimensional porous structure, making it an ideal precursor for the preparation of biomass-derived heteroatom doped porous carbon. In this study, the loofah sponge, urea, and ferric sulfate nonahydrate were used as the carbon source, nitrogen source, and iron source, respectively. After simple impregnation and high-temperature carbonization, iron/nitrogen co-doped porous carbon (Fe@NC) was successfully prepared. The characterization results of SEM, XRD, and Raman showed that the prepared Fe@NC maintained the porous structure of biomass precursor, and the Fe/N co-doping was beneficial for improving the specific surface area and defect degree of carbon materials. Then, it was found that Fe@NC could serve as favorable catalysts for PMS activation, resulting in the efficient degradation of RhB. The effects of carbonization temperature, PMS concentration, the dosage of porous carbon, initial pH value of the solution, anions, and humic acid on the RhB removal efficiency were discussed in detail. The results showed that under the optimized conditions, the removal efficiency of RhB in the Fe@NC-800/PMS system would reach 99.9% within 20min and the rate constant was 2.5 times, 12.7 times, and 22.7 times that of Fe@C-800 /PMS, NC-800/PMS, and C-800/PMS systems respectively. Results of the inhibition experiments and EPR analysis revealed that SO₄^·-, ·OH, and ¹O₂ were the main active species in the Fe@NC-800/PMS system. The degradation of RhB could be achieved through both radical and non-radical processes. In addition, the cycling experiments demonstrated the good reusability of Fe@NC-800, and the metal leaching could be effectively inhibited.

The refractory organic matter sulfonated phenolic resin (SMP) was treated with ferrate. The influences of various factors on the COD_Cr removal rate of SMP were studied. The optimal conditions were determined. When the initial concentration of SMP was 0.05% (mass ratio), the ferrate was 1.2g/L, the pH=13 and the reaction time was 2h, the COD_Cr removal rate of SMP was 79.4%. The amount of ferrate had a great influence on the COD_Cr removal rate. Different concentrations of SMP should choose different ferrate dosage. The removal rate of SMP was still dominated by oxidation and flocculation accounted for a low proportion of the total removal rate. Combined with UV-Vis, GPC and GC -MS analysis, it can be concluded that the sulphomethyl structure of SMP was completely degraded, and the macromolecular backbone of SMP was broken to generate substances with a molecular weight of about 1300 with a benzene ring. When the backbone was degraded to a certain degree, the benzene ring began to be oxidized and the ring-opening reaction occurred to form small molecular organic hydrocarbons, which were eventually oxidized to CO₂ and H₂O.

After the process of in-situ pyrolysis mining of oil shale, its lithology and composition would change significantly, then the groundwater intrusion of the mining area will lead to water pollution. Therefore, this study explored the effects of heavy metals and extractable petroleum substances released from oil shale char at different pyrolysis temperatures on the groundwater quality. The pyrolysis of oil shale semi-coke which at 100—500℃ under normal pressure was selected for physical property characterization experiments, and it was divided into two groups with particle size ≤2mm. The study was on the specific surface area, and the microstructure of oil shale and the changes of proportion of elements before and after pyrolysis of oil shale were measured. At the same time, the pyrolysis semi-coke was soaked to detect the content of heavy metals Fe, Mn and Cr in water samples. The maximum concentration reached 9.07mg/L, 5.26mg/L, 0.053mg/L, and the result showed that it exceeded the class V water standard of groundwater quality standard (GB/T 14848—2017), in the mean while the analysis showed that the excessive heavy metal elements were mainly caused by the immersion of mineral components of oil shale into water after pyrolysis, which was related to the changes in physical properties of oil shale caused by in-situ pyrolysis. At the same time, it was found that the effect of extractable petroleum substances on groundwater reached the maximum when the pyrolysis temperature was 400℃.