Microbubbles have several physical characteristics, such as large gas-liquid contact area, fast gas dissolution rate, slow rise speed, and long residence time in the water, etc., which are suitable for the biological fermentation process with high gas-liquid mass transfer efficiency. In this study, several kinds of microbubble generators, like microbubble diffuser, microporous membrane, fluid oscillator coupled microporous membrane, and microbubble aeration agitator were introduced. The application of microbubble generator coupled stirred bioreactor, airlift bioreactor or biofilm reactor in biological process was described. The research progress of carbon dioxide microbubble bioreactor was summarized. This study reveals that the research of microbubble coupling bioreactor is in the early stage, and the study on the scaling up and energy consumption is limited. The continuous progress of microbubble coupled bioreactor is vital to the development of industrial biotechnology, petrochemical industry, sewage treatment, and resource reuse.

Hydrocyclone, as a typical non-thermal physical separation equipment, has the technical advantages of simple structure, high separation efficiency, large processing capacity, low operation, and low maintenance costs, etc. It has been widely used in many fields such as petroleum, chemical industry, environmental protection, and mining. With the development of intensified technology for the hydrocyclone separation process, the accuracy of hydrocyclone separation has also developed from the millimeter level to the micron, nanometer, and even ionic molecular level. Based on the principles and engineering applications of the intensification of the hydrocyclone separation process, the research progress of the new intensification technologies for the hydrocyclone separation process is introduced in this study. The testing methods of continuous phase flow from one-dimensional point to two-dimensional surface, and then to three-dimensional body are systematically summarized. A synchronous high-speed motion analyzer (S-HSMA) system, based on microfluidic and high-speed camera, was developed for the detection of the velocity of fast spirally moving particles. The new phenomenon of high-speed self-rotation of particles in hydrocyclone were detected for the first time. The particle self-rotation in hydrocyclone has achieved a breakthrough from phenomenon discovery to engineering application. The new mechanisms of absorption, extraction, and desorption enhancement by particle self-rotation in hydrocyclone were introduced, as well as the novel intensification methods and equipments for bubble enhanced oil-water separation, particle sequencing enhanced micro-particle removal, self-rotation enhanced oil removal in porous media.

The dispersibility of nanoparticles is a key problem for their applications. A new generation of nanomaterials-monodispersed nanoparticle materials as so-called nanodispersions can be dispersed in solvents with good transparency or obvious Tindal effect. Compared with traditional nanopowders, the nanodispersions show better dispersibility in applications with enhanced nano effects. Among the relevant researches, the preparation of nanodispersions with a high solid content, high stability and high transparency at low cost and large scale is still a great challenge. In order to solve this problem, based on high-gravity reactive crystallization process with intensified molecular mixing, as well as surface design and property control of particles, our group firstly proposed a new method of high-gravity reactive crystallization coupled with modification separation ("high gravity plus" method) by properly introducing surface modification-separation process for the requirements of terminal engineering applications to prepare transparent nanodispersions. In this article, the researches on the controllable preparation of transparent nanodispersions by “high gravity plus” method and their applications in our group in recent years are summarized, and the future research is prospected.

Ozone-based advanced oxidation process (AOP) is one of the cutting-edge technologies in wastewater treatments due to its advantages of green-efficiency, wide applicability and simple operation. However, its absorption and utilization efficiency in traditional reactors is low. Rotating packed bed (RPB) applies high-speed rotating packing to generate high-gravity, splitting the liquid into thin film, filaments or small droplets. Hence, the mass transfer and decomposition efficiency of ozone can be significantly enhanced by the high gas-liquid interface area, interface renewal rate, and forced turbulence of internal fluid. This technology has the prominent advantages for the strengthening of ozone-based advanced oxidation process with limited mass transfer. In this study, the principle of enhanced ozonation by high gravity as well as the coupling applications of high gravity with AOPs such as O₃, O₃/H₂O₂, O₃/Fenton, O₃/PS, and catalytic ozonation in organic-based wastewater treatments are introduced. The advantages and technological breakthroughs of high gravity are discussed, and its potential economic and environmental benefits in wastewater treatments are summarized. The development of novel functional packing and large-scale RPB is proposed. This study could provide theoretical and technical implications for the industrial amplifications.

Membrane dispersion has been reported as an emerging technology for realizing the rapid interphase mixing and mass transfer. Gas/liquid-phase reactant can be uniformly dispersed into another phase in microscale size through the micro/nano-pores of porous membranes. This review summarizes the principle and characteristics of membrane dispersion. The latest progress of membrane dispersion on the preparation of micro/nanostructured powders and the intensification of heterogeneous catalysis is introduced. In the aspect of the synthesis of micro/nanostructured powders by membrane dispersion, the mixing mechanism in membrane dispersion, as well as the applications in the preparation of polymer microspheres and inorganic nanoparticles, are described. For the heterogeneous catalytic reactions intensified by membrane dispersion, the works related to the experimental studies and theoretical calculation of gas-liquid two-phase flow intensified by membrane dispersion are reviewed. The key factors related to bubble formation and mass transfer characteristics are described, and the applications in intensifying the heterogeneous catalytic reactions are introduced. Furthermore, the future research directions of membrane dispersion are proposed.

Membrane separation is energy-saving and highly efficient, which shows important applications in the fields of water treatment and gas separation. Two-dimensional (2D) membrane is a kind of novel membrane, assembled from 2D nanosheets with a high aspect ratio. They are easily manufacturable and have good mechanical strength with designable and controllable structure. In the laboratory, 2D membrane has been widely used in organic solvent dehydration, nanofiltration, ion rejection, gas separation, etc, which is expected to break through the performance limit of traditional separation membrane. However, till now, the study on 2D membrane is still in its infancy. It is still challenging to accurately design and tune the structure of 2D membrane to achieve the desired separation performance. This study summarized several strategies of the structure design and tuning, which include cross-linking, guest materials intercalation, surface modification, etc., aiming to improve the permeability, selectivity, and stability of 2D membranes. This information can help to improve the separation performance by tuning the interlayer spacing, channel orderliness of the 2D membrane, and the interaction between the nanosheets.

Hydrogenation technology is an indispensable main means of producing clean oil products and improving product quality, which is the core of refining and chemical integration. Despite decades of development, hydrogenation technology has made considerable progress, but there are still several problems such as high investment and operating costs, high energy consumption, etc, which are unable to meet the requirements of petrochemical companies for sustainable development. The progress of low-investment and low-energy hydrogenation technology in China is briefly described, such as hydrocracking catalyst grading technology for strengthening the catalytic reaction process, light cycle oil hydroconversion technology with enhanced reaction conditions, low energy consumption and low investment SHEER technology to strengthen the heat transfer process, and liquid phase circulation hydrogenation technology for enhancing mass transfer process. It is proposed that future hydrogenation technology will play an increasingly important role as a hub for refining and chemical integration. It will achieve a coordinated spiral upgrade through coupling and perfecting process intensification technology. The complex system reaction behavior of the upgraded hydrogenation technology is closer to the intrinsic reaction state. The hydrogenation technology will achieve a high degree of atomic economy, which is more in line with the future needs of the green development of human society.

Selective hydrogenation of acetylene catalyzed by Pd-based catalysts is crucial in the production of polymer-grade ethylene from both steam cracking process of naphtha and the coal-based acetylene feedstock. The traditional Pd-based catalysts are expensive, and exhibit poor selectivity and stability. This review summarizes recent research advances in the structure-sensitivity of catalyst and the corresponding regulation of catalysts' structures. The effects of particle sizes, morphologies and electronic structures of active metal nanoparticles on the catalytic performance are demonstrated, which provides the target of structure regulation toward enhanced performance. Furthermore, the research progress related to the precise structure regulations for the catalysts are summarized based on the characteristics of hydrogenation of acetylene, including the introduction of a second metal to prepare alloy or intermetallic compounds catalysts and the design of single atom and single atom alloy catalysts (SAC and SAA). By rationally regulating the structure of catalysts, we could optimize the adsorption/desorption behavior of key species involved in the reaction and the reaction kinetics, and then the selectivity and stability of catalysts can be significantly improved. In the future research, the rational design of highly efficient, stable and low-cost catalysts for the reaction would be the key issue.

Photo(electro)catalytic nitrogen reduction technology has many advantages over the traditional, well-established Haber-Bosch process for nitrogen fixation, such as the utilization of natural sun light as the energy source and significantly lower pressure and temperature to affect the reaction process. These advantages result in the use of the photo(electro)catalysis for nitrogen fixation being of lower energy cost and lower CO₂ emissions than that of the Haber-Bosch method, making it one of the most promising emerging synthetic ammonia technologies. The key to photo(electro)catalytic nitrogen fixation lies in the design of the catalyst and the optimization of the catalytic reaction system. Based on the fact that nitrogen is a non-polar molecule, has a low water solubility, and is chemically inert, it is difficult to be activated, and so the overall efficiency of nitrogen reduction to ammonia is relatively low. Increasing the utilization rate of photogenerated carriers also significantly affects the overall catalytic efficiency. This article introduces the reaction process and mechanism of photo(electro)catalytic nitrogen reduction to ammonia, mainly from the specific reaction processes of promoting the dissolution and diffusion of nitrogen, adsorption and activation of nitrogen, and enhancement of the separation and transmission of photogenerated charge carriers. Moreover, the latest research status based on the enhancement of the above reaction process in the field of ammonia synthesis are summarized. Finally, some deficiencies in the current research of photo(electro)catalytic ammonia synthesis are highlighted, and the future development trends in this field are analyzed and assessed.

Due to the exceptional ring strains, epoxides have remarkable reactivity, which can be reacted with nucleophiles to product the various synthetic intermediates via ring-opening reaction under the acid or base catalysis. The regioselectivity and stereoselectivity of ring-opening reactions of epoxides are the central topics of synthetic chemistry. This review provides a summary and perspective of the extensive research, aiming to put insight into the development of process strengthening for ring-opening of epoxides. The effects of different strengthening strategies are introduced from the aspects of intensification of new material, intensification at the presence external field and intensification of process equipment. Meanwhile, the effects of new porous materials, metal oxides, and ionic liquids on the nucleophilic ring-opening reactions of epoxides are also emphatically analyzed. In the practical industrial processes, the conversion and selectivity of the nucleophilic ring-opening reactions of epoxides in strengthening technologies are still low, and the energy consumption is high. Furthermore, this study reveals that the establishment of the coupling process of various strengthening technologies based on the ring-opening reactions of epoxides is the future research direction.

Deep eutectic solvents (DESs) possess properties, as a new generation of green solvent, obtain similar features with ionic liquids, such as low volatility and designable. With the advantages of less expensive and easier preparation, DESs attract much attention in many applications as alternatives to conventional organic solvents, especially in extractive separation of mixtures. In this paper, the development of DESs applied in extraction is introduced. The applications of DESs in liquid-liquid extraction, associative extraction with in situ formation of DESs, and the extraction through DESs decomposition are described. The features and problems of each processes are analyzed. The stability of DES in the processes of extraction and the methods for DES regeneration are introduced. The development of theory for the description of DES and extraction mechanisms are reviewed. Finally, the challenges, for instance, the DESs theory, extraction mechanisms, and cyclic stability are discussed. The industrial applications and further research trend of DESs are prospected.

As a kind of green solvents, ionic liquids have been widely applied in the enhancement of extraction processes. However, high production cost and special hydrodynamics associated with high viscosity are among the main concerns that hinder industrial applications of ionic liquids. The emergence of microchemical technology provides an efficient and enhanced platform for continuous extraction processes with the use of ionic liquids. In recent years, the coupling enhancement between microchemical technology and ionic liquid has received increasing attention in the field of extraction separation. In this article, the basic introduction of the microflow extraction technology, the characteristics of extraction processes with the use of ionic liquids, ionic liquid based liquid-liquid two-phase flow patterns, mass transfer and enhancement mechanism in microreactors are mainly reviewed. The applications of ionic liquids for the extraction of metals and organic substances, and the research progress of the process scale-up for ionic liquid based extraction in microreactors are highlighted. The prospects about ionic liquid based multi-step extraction, functionalized ionic liquid based extraction and its corresponding scale-up of microflow extraction are proposed.

The massive combustion of fossil fuels not only advanced the process of industrialization but also initiated severe climate and environmental issues. To mitigate ever-rising atmospheric CO₂ concentration and to achieve the 2℃ goal set by the Paris Agreement, CO₂ capture techniques have received increasing attentions and researches, and some technologies have already been demonstrated on pilot scale. In the context of constantly pushing forward energy conservation and emission reduction, intensifying current industrial processes via CO₂ capture is an emerging aspect of interest. In doing so, the original processes can be operated in a much more efficient manner with improved product quality and dramatically reduced CO₂ emission, making it a very prospective technical route. Here, starting from the mainstream CO₂ capture techniques, the advances of process intensification techniques towards CO₂ capture are presented with focus on the hydrogen production via steam reforming, water-gas shift and biomass gasification processes intensified by CO₂ capture, and CO₂ hydrogenation, CH₄ dry reforming and chemical looping combustion processes integrated with CO₂ capture. The techniques regarding utilization and conversion of captured CO₂ has also been briefly reviewed.

Side-reactor column (SRC) configuration is a discrete integration technology in which the reactors and distillation column are not only independent but also coupled with each other. The limitation of operation conditions in traditional reactive distillation (RD) could be overcame due to the different location of reaction and separation, expanding the RD application areas and facilitates industrial amplification. This study reviewed the SRC technology from basic to application. The equivalence of SRC and RD were analyzed from the aspects of conversion, selectivity, temperature, and composition profile. The advantage of SRC was the flexible adjustment of operating conditions, which could realize the perfect match between reaction and separation capacity. The developments in steady state simulation and optimization, dynamic simulation and control strategies of SRC were introduced. It also summarized the current applications of this technology from two aspects: integrated technology of reaction and distillation under different working conditions, convenient catalyst loading and reactor design. The future research and application of SRC were prospected from the aspects of optimization design theory, advanced control methods, comprehensive utilization of energy, enhanced enzyme-catalyzed reaction.

Oil-water mixtures are widely present in various industrial processes. Its properties and enhanced separation technologies are one of the most important research topics in the field of chemical separation. The conventional physical separation technologies, such as sedimentation, cyclone, and electric coalescence, etc are used in combination with chemical agents for demulsification, which have several problems, such as low separation efficiency and secondary pollution. In recent, the development of enhanced separation technology represented by multi-physical field coupling and new separation materials has attracted wide attention. In this study, the separation of the large volume of water-in-oil (W/O) crude oil emulsion and oil-in-water (O/W) oily wastewater emulsion in the petroleum industry is investigated. The formation, classification, and basic physicochemical properties of oil-water mixtures are described. It pointed out that the breaking of emulsion stability is the key to enhance the separation based on the analysis of microscopic interfacial film. Various separation technologies and their characteristics are systematically introduced from the aspects of conventional separation technology, applied field, separation materials, and coupling, etc. Finally, the further research trends of enhanced oil-water separation technology are prospected.

China is abundant in rare earth resources with wide distribution and complete range of types. However, a large amount of wastewater contained rare earth ions and other pollutants is produced by rare earth leaching and acid precipitation processes. The health of people and ecological environment could be affected dramatically, if wastewater was discharged into rivers or groundwater. Extraction technology is widely used in the separation of rare earth elements. However, the traditional extraction technology and equipment has several disadvantages, for instance, large consumption of extractant, serious loss of solvent entrainment, low extraction efficiency, and easy emulsification etc. In recent, gas-liquid-liquid microdispersion extraction technology is an important research content in the fields of microfluidics, microchemicals, and microanalysis, which has the unique advantages of fast mass transfer and short phase separation time. This review introduced the research progress of gas-liquid-liquid microdispersion extraction technology in the field of enrichment and recovery of low-concentration rare earth ions. These contents included the preparation and regulation law of gas-liquid-liquid double emulsion, the flow pattern of three-phase flow in microchannels, and the application of gas-liquid-liquid microdispersion technology in the field of rare earth ion extraction and recovery and the scale-up of gas-liquid-liquid microdispersion extraction technology. The current research results reveal that the gas-liquid-liquid microdispersion extraction technology has unique advantages in the extraction and recovery of low-concentration rare earth ions, which is expected to solve the problem of rare earth leaching tailings treatment. This study summarized the research progress in the above aspects, and prospected the future development direction.

Reactive and antisolvent crystallizations are widely used techniques for the manufacture of inorganic and organic chemicals, such as catalysts and active pharmaceutical ingredients. High supersaturation conditions are usually created in these processes, resulting in fast primary crystallization kinetics, especially nucleation rate. Thus fast and sufficient mixing of different reactants or antisolvent and solution before the onset of crystallization is required to avoid the spatial inhomogeneity of supersaturation, which can lead to crystal products with undesirable properties. The analytical and predictive abilities associated with modelling and numerical simulation can provide insights into the mechanisms of the process phenomena and facilitate the design and optimization of operating conditions and crystallization devices. This paper reviews the development of process intensification approaches and modelling studies of reactive and antisolvent crystallizations. Firstly, process intensification studies by means of diverse crystallization devices, external fields and membrane technology are presented. Secondly, population balance equation and extensively adopted micromixing models are introduced, including engulfment model and joint composition probability density function-based micromixing models. Finally, modelling studies on liquid-liquid and gas-liquid reactive crystallizations and antisolvent crystallization are summarized, in which similar studies are analyzed by comparing the predictive performance with each other. In view of the limitations of existing studies, some perspectives on further development and improvement are presented.

The research progress on technologies for producing para-xylene (PX), including toluene disproportionation and trans-alkylation, xylene isomerization, methanol aromatization, selective disproportionation of toluene, and selective alkylation of toluene with methanol, has been reviewed in this paper. The pros and cons of these technologies have been discussed. Compared with methanol to aromatics technology, selective alkylation of toluene with methanol has significant advantages of high PX selectivity, short process and no adsorption separation unit, which is more favorable to realize the development of coal to PX industry. By coupling a unit for selective alkylation of toluene with methanol, the aromatics complex in petrochemical plants can increase PX production by more than 40% and doesn’t produce benzene ideally. The development trend in PX production technology is proposed: the technology of selective alkylation of toluene with methanol can promote the clean and efficient utilization of coal, ensure the polyesters industry safety, and is helpful to open a potential way for the coordinated development of coal chemical and petrochemical industries.

Polyoxymethylene dimethyl ethers (DMM_n), as a new type of green and environmentally friendly diesel fuel additive, can effectively reduce the emission of pollutants after combustion and improve the industrial structure of coal chemical industry with coal-based methanol as the source because of its high cetane number and oxygen content. Therefore, the synthesis process and industrialization process of DMM_n are widely concerned by scholars at home and abroad. The domestic and foreign DMM_n synthesis process, industrial layout and future development prospects are reviewed. Based on the existing process, the characteristics of various synthesis routes of methanol to DMM_n through different intermediate products are summarized. Through the analysis of the key factors restricting the DMM_n industrialization process, especially the sharp drop in oil price caused by the global COVID-19, which has brought a huge impact on the coal chemical industry, reactive distillation is considered as the most competitive technology route for DMM_n product promotion and industrial application in the future.

In this study, the markets and technology development trends of coal-based bulk chemicals have been systematically analyzed. It is urgent to develop the downstream applications to increase the demand of the coal-based chemicals because the capacity of ammonia, urea, and formaldehyde is serious surplus in China. The import dependence of methanol, ethylene, and propylene has shown a downward trend with the coal to methanol (CTM) and methanol to olefin/propylene (MTO/MTP) technologies development. However, the production ratio between ethylene and propylene needs to be further optimized. In recent, the development of coal-based natural gas, para-xylene and ethylene glycol technologies were the research hotspot. Respectively, the coal-based ethylene glycol industrialization reduced the input dependence from 75.0% to 54.4%, while the quality of the ethylene glycol polyester grade still needed to be improved. Due to the shortage of oil and gas resources, natural gas and para-xylene have been dependent on imports for years in China. Therefore, it is of great strategic significance to the energy and chemical industry via developing the technologies of coal-based natural gas and coal-based para-xylene. The thought of coal chemical technology development has been proposed, which focuses on the extension of the downstream industrial chain of ammonia and formaldehyde bulk chemicals, solution of the poor quality of coal to ethylene glycol products, and breakthrough of the relevant research on the industrialization of methanol-toluene aromatization.

Polymethoxy dimethyl ether (PODE_n), as a potential blend component of diesel, can effectively reduce emission of the pollutants from insufficient combustion of diesel. However, the technological bottleneck in scaling up and operation of the reactor has hindered commercial production of PODE_n. Aiming at modelling design and operation of the PODE_n reactors, this article reviews advances in reaction kinetics of PODE_n synthesis in recent years for a variety of synthetic processes and summarizes the urgent issues in the synthesis of PODE_n.The analysis shows that water has an effect on the reaction rate and changes the products distribution of PODE_n.The reaction with methylal as the end group source has less by-products due to the absence of water, which can reduce the difficulty of products separation and greatly simplify the kinetic model. Simultaneously,the research progress of chain growth mechanism is briefly described. It is proposed that insights into the reaction mechanism of PODE_n synthesis are critical to construct a universal kinetic model in the future, so that it can be applied to process optimization and reactor scale-up design.

Aromatics production in China is now facing the difficulty of shortage of oil resources, while the abundant coal resources and the current excess methanol capacity can provide low-cost raw materials for the production of aromatics from coal-based methanol, which is of great significance for the energy security of China. This article summarizes the recent research progress of methanol to aromatic hydrocarbon (MTA) technologies at home and abroad, and then introduces the MTA fixed bed and fluidized bed technologies respectively. In view of the disadvantages of traditional MTA process, such as complex products, large energy consumption in separation and poor economic benefits, the more economical one-step methanol to p-xylene (MTPX) and one-step methanol to p-xylene and low carbon olefins (MTO&PX) technologies are summarized. In view of the insufficient stability of traditional MTA catalysts and other deficiencies, the comparison introduces two novel routes of methanol directly to aromatics and methanol to aromatics through dimethyl ether or low-carbon olefins. The results show that the route of methanol to aromatics through low-carbon olefins has the advantages of long catalyst life and easy adjustment of product composition. Finally, this paper points out that zeolite confinement effect, new technology for molecular sieve surface modification, and metal-acid dual active center synergistic effect are important directions for future MTA research.

In this study, a novel middle vapor recompression distillation column (MVRC) was proposed and compared with the conventional distillation column (CD). Meanwhile, their performance was investigated by the separation of the propylene and propane. Process modeling and optimization were realized by using the Aspen Plus simulation software, and the energy-saving, overall exergy loss, and economic benefits were discussed according to different ratios of propylene to propane. The results show that the MVRC has good energy-saving effect compared with CD, especially, it is the most significant when the ratio of propylene to propane is 3∶1. The MVRC has a significant overall exergy loss reduction compared with CD, and almost unaffected by the different ratios of propylene to propane in the feed. In terms of economic investment, the large economic benefit is obtained in the MVRC and the total annual investment saving rate is affected little by the feed composition ratio. It shows that the middle vapor recompression distillation column has good adaptability in feed composition ratio.

ZSM-5 zeolites were synthesized with different templates by hydrothermal method and characterized by XRF, XRD, SEM, NH₃-TPD, Py-FTIR, and ²⁷Al MAS NMR. The effect of templates on the catalytic performance of ZSM-5 zeolites in the trioxane synthesis was investigated. The results indicated that types of templates affected the distribution of acidity, the surface acidity and the particle size of the catalyst of the ZSM-5 zeolites. Acid sites located on the intersection of straight channel and S-channel, small particle size and high surface B acid /L acid ratio were favorable to enhancement of trioxane selectivity. Synthesized with tetrapropylammonium hydroxide, the ZSM-5 zeolite, of which the average particle size was 240nm×240nm×150nm and high acid sites distributed in the intersection of straight channel and S-channel, exhibited the formaldehyde conversion of 30.15% and trioxane selectivity of 88.35%.

Alkylation of toluene with methanol is a promising technology for p-xylene?production. However, this process is exothermic and the easier coke deposition will cause a relatively quick catalyst deactivation. Accordingly, the fluidized bed should be an appropriate reactor due to the excellent heat transfer performance and easy realization of continuous catalyst regeneration. In this paper, the discrete particle model was applied for a numerical study on alkylation of toluene with methanol in a fluidized bed reactor. And some conclusions were as follows for a given flow rate of toluene. If the toluene/methanol feed molar ratio reduced, the p-xylene yield and selectivity would increase, while the mole ratio of p-xylene to olefin had a sharp decrease. Both of the toluene conversion and methanol conversion can be well improved at elevated pressures, following with a reduction in p-xylene selectivity. Staged methanol feeding can not only improve the toluene conversion, but also adjust the product distribution. Gas backmixing in fluidized bed reactors would lower the p-xylene selectivity. And the change of the flow pattern under different operating conditions followed with different gas-solid contact efficiency and local partial pressure of the reactants, which would also influence the product distribution. These results can give some guidance for the optimization and scale-up of the fluidized bed reactor.

As one of the main directions of energy storage technology, the phase change thermal energy storage technology is widely used in renewable energy utilization, i.e. solar and wind power generation, waste heat recovery, and distributed energy system. Based on the analysis of relevant literatures, phase change materials (PCM) are classified, meanwhile, the properties, advantages and disadvantages, and suitable application condition of the PCM are also introduced in detail. Furthermore, the research progress of composite phase change technology and heat transfer enhancement technology are mainly discussed, since the PCM has the defects of leakage, corrosion, supercooling, poor heat conduction, etc. Finally, the problems in PCM utilization are pointed out and the future development directions are also prospected, which are reliable composite phase change technology, efficient heat transfer enhancement technology and improvement of the PCM thermal stability. This review has important reference value for the future research and development of the phase change thermal energy storage technology.

Four catalysts prepared from H-MCM-49, H-ZSM-5, H-ZSM-22 and H-ZSM-35 molecular sieves were used for the hydrocracking and hydroisomerization of the long-chain normal bio-paraffins obtained by hydrodeoxygenation of biomass oil to bio-jet fuel. Their physicochemical properties and catalytic performance were investigated. On this basis, a series of Pt/ZSM-35 bifunctional catalysts with low Pt loadings (0.1%, 0.2%, 0.3%) were prepared by using H-ZSM-35 as the carrier. The performance of the Pt/ZSM-35 catalysts in the hydrocracking and hydroisomerization of long-chain normal bio-paraffins to bio-jet fuel was evaluated by the conversion of the bio-paraffins, the selectivity of C₉—C₁₆ products, and the yield and the iso/n-paraffin ratio of bio-jet fuel. Then the reaction conditions were optimized. The results showed that the strength and the amount of the strong acid center of H-ZSM-35 were the highest. Meanwhile, due to the small pore and large spherical cage, H-ZSM-35 possessed a certain amount of hydrocarbon capacity and good shape-selectivity. The Pt/ZSM-35 catalysts with Pt loading of 0.1%—0.3% exhibited high activity and high selectivity to bio-jet fuel. The optimized reaction conditions were obtained as 320℃, 1MPa, 0.7h^-1 and H₂/n-paraffin volume ratio of 840∶1. The conversion of long-chain normal bio-paraffins over the 0.1%Pt/ZSM-35 bifunctional catalyst reached 84.3%, and the yield of bio-jet fuel was as high as 41.1% with an iso/n-paraffin ratio of 1.34. In the long-term operation test for 81h, the 0.1% Pt/ZSM-35 catalyst showed good stability.

As new kind of nano-porous structured material, SiO₂ aerogels have excellent properties such as high specific surface area, low thermal conductivity and refractive index, and hence are widely used in various fields. However, the low mechanical strength and brittle quality of SiO₂ aerogels severely limit their industrial application. Therefore, the improvement on the mechanical properties of SiO₂ aerogels is essential for its widespread application. Recently, the introduction of functional components into SiO₂ aerogels has become one of most effective methods to enhance their strength and flexibility. In this frontier review, the preparation and modification of SiO₂ aerogel have been introduced first. The design of nanoparticles-SiO₂ aerogel composites is then discussed in detail. The influences of different dimensional nanomaterials such as 0D metal oxides nanoparticles, 1D nanotubes/nanofiber, 2D graphene oxide nanosheets and 3D metal-organic frameworks on the structure and surface physicochemical characteristics of the aerogels are analyzed. Finally, the industrial application potentials of SiO₂ aerogel composites in environmental adsorption/catalysis are discussed.

Three CuO(y)/Cu_xCe_1-xO_δcatalysts with different compositions were prepared and evaluated for the removal of trace CO in liquid-phase propylene at low temperature. The effects of the surface Cu species and Cu_xCe_1-xO_δ solid solution on the structure, redox ability, surface state and CO oxidation activity were investigated, aiming to gain guide for further modification of the catalysts and finally to realize the industrial application. The catalysts were characterized by XRD, TEM, XPS, H₂-TPR, CO-TPD, etc. which showed that in the carrier Cu_xCe_1-xO_δprepared by citric acid complexation, the copper particles could enter into the crystal lattice of cerium oxide, which enhanced the reducibility of the catalyst for oxygen activation. And the catalyst improved by impregnation method on this carrier, had more reduced and highly dispersed Cu species on the surface, which was beneficial to the chemisorption of CO. Therefore, the CO oxidation was promoted by the synergistic interaction. CuO(0.40)/Cu_0.1Ce_0.9O_{δexhibited the highest activity for CO conversion. Under the conditions of 50℃, LHSV=8h^-1 and 3.0MPa, the volume fraction of CO in liquid propylene decreased from 1.0×10^-5 to 2.65±0.27×10^-8 with good stability, which met the requirements of "polymer grade" propylene.}

The carbon thermal reduction of phosphate rock with different dopants of K₂CO₃, Na₂CO₃, NiSO₄ and K₂CO₃-NiSO₄ were compared and analyzed. The results showed that the reaction progress of the systems with alkali metals doped was slightly better than that of other systems at 1200℃ because it was easier to produce liquid phase that was conducive to the diffusion. Comparing the XRD patterns at different temperatures of the doped system with those of the undoped system, we found that the dopant only strengthened the reaction progress, and no new substance was produced. There was also a significant difference in the flow temperature of the residue after doping. At 1250℃, the flow temperature of the residue with alkali metal dopants was relatively low, which decreased with the increase of the temperature. However, the flow temperature of the mixed doping system and the doped system with nickel sulfate was lower than that of the alkali metal system at 1350℃. From the SEM analysis of the residue at 1300℃, it can be seen that the appearance of the residue from the doped system was basically the same as that from the unadulterated system, indicating that the doping did not change the appearance of the residue, which was solid and met the solid slag discharge requirements of kiln phosphoric acid.

Catalytic reduction of α-pinene was achieved in one pot at room temperature using Span as stabilizer, NiCl₂·6H₂O as catalyst precursor, and NaBH₄ as an alternative to the exogenous flammable and explosive hydrogen. In this catalytic system, the effects of Span type, reaction medium, amounts of NaBH₄ and reaction time on the reduction reaction were investigated, and the optimum reaction conditions were obtained as follows: Span-80 as the stabilizer, methanol as the reaction medium, and 0.5 molar equivalent of NaBH₄ (relative to α-pinene) , 5mol% NiCl₂·6H₂O, reaction at room temperature for 5 hours, under which the conversion of α-pinene and the selectivity of cis-pinane reached 98% and 99%, respectively. In addition, the catalyst could be recycled for 3 times. The leaching and morphology of the catalyst during the recycle were studied by ICP-AES and TEM. The results showed that the leaching of Ni during the recycle was only 0.2%. The particle size of the catalyst after one run was about 4.2nm with uniform dispersion. However, after three cycles, the particle size of some Ni nanoparticles became larger due to aggregation, which may be the main reason for the decrease in the catalysis activity. Besides, XPS and a series of poisoning experiments showed that the active species in the catalytic reaction were probably homogeneous in nature, and the in-situ formed nickel nanoparticles may only serve as a “reservoir” of the catalytic species. Compared with the traditional α-pinene hydrogenation process, the proposed process has the advantages of safe, mild, and easy operation and high selectivity.

Graphene oxide modified superabsorbent combines the advantages of graphene oxide and superabsorbent, and has a broad application prospect in the fields of water treatment adsorption, drug slow release and tissue engineering. At present, the preparation methods, properties and applications of graphene oxide modified superabsorbents have not been reviewed. Therefore, this paper was mainly divided into four parts to review the research progress of graphene oxide modified superabsorbent in recent years. In the first part, the structural properties of graphene oxide and its properties as a superabsorbent modifier were briefly introduced. In the second part, the main preparation processes of graphene oxide modified superabsorbent were summarized. The third part mainly presented the effect of graphene oxide on the microstructure and properties of superabsorbent. Finally, the applications of graphene oxide modified superabsorbent in wastewater treatment, reduction of “heat island effect”, flexible devices and medical materials were proposed, and the existing problems were analyzed, which provided the references for the follow-up research and application of graphene oxide modified superabsorbent.

Detonation method, which is regarded as a new method of preparing nanoparticles (NPs), has the advantages of simple operation, higher efficiency, lower cost, saving energy and environmental protection, etc. However, due to the complexity of the synthesis process and special properties of NPs, the explosive synthesis of NPs is easy to agglomerate, which not only destroys the ultra-fineness and uniformity of NPs, but also affects their superior performance. At present, the research on the NPs preparation by detonation method as well as their agglomeration control has been one of the hotspots in the field of explosive processing. In this study, research progress of NPs synthesized by detonation method is generalized. The latest achievements in controlling agglomeration of NPs and improving the dispersibility of NPs are summarized from the aspects of the main influencing factors, such as the physical and chemical properties of NPs, the preparation process, the purification process, the dispersion process, and the agglomeration models. The research hotspots and key problems, which needed to be solved urgently, are also presented.

Superhydrophobic surfaces have attracted tremendous attention due to their special wettability and wide application. However, superhydrophobic surfaces are highly susceptible to mechanical or chemical attack, resulting in loss of low surface energy substances or destruction of hierarchical micro/nanostructures, and eventually the loss of superhydrophobicity. Therefore, it is still a big challenge to construct a durable superhydrophobic coating in the field of superhydrophobic. In this paper, the recent progress of abrasive resistance and self-healing superhydrophobic surfaces were summarized. Firstly, the methods for improving abrasive resistance of superhydrophobic surface were concluded from forming covalent bonds, introducing elastic materials and using substrate surface to construct hierarchical micro/nanostructures. Secondly, the ways for endowing self-healing function to superhydrophobic coatings were reviewed from releasing low surface energy substances, regenerating topographic structures and bulk self-healing. Moreover, the industrialization status of durable superhydrophobic surface was discussed. Finally, the future research and development of durable superhydrophobic surfaces were also prospected in order to provide references for fabrication of durable superhydrophobic surfaces for widespread applications.

A heat exchange testing system for off-peak electricity energy storage was built. The thermophysical properties of non-phase change solid heat storage materials, such as corundum ball, were measured by a data recorder and a Hot-Disk thermal constant analyzer. The heat charge and discharge characteristics of fly ash, magnesia, corundum sand and corundum ball were studied both experimentally and computationally. The influences of the type and particle size of the heat storage materials on the heat charge and discharge characteristics were analyzed. The thermal storage densities and comprehensive heat transfer coefficients of different materials were obtained. Combined with FLUENT unsteady state simulation method, the variation of heat charge and discharge temperature fields of the heat storage device with materials of different particle sizes were simulated. The results showed that the corundum ball provided enough heat continuously and thus could be used as a good heat storage material. The heat storage density and comprehensive heat transfer coefficient increased with the size enlargement of corundum sand, and the effective heat discharge time was longer accordingly.

FO membranes were constructed by interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) directly in the porous spaces of polyester non-woven (NV) fabrics. The multi-layer three-dimensional (3-D) polyamide structure formed by the NVC-FO membrane inside the non-woven fabric was distributed inside the PET support material with a depth of 30~50μm. This relatively loose 3-D polyamide network not only had a large water-permeable surface area, but also avoided high salt leakage caused by thin-layer polyamide defects with a low reverse salt flux. Further research found that reducing the monomer concentration (1%~0.01% MPD, 0.5%~0.005% TMC) within a certain range can form a wider 3-D polyamide network structure, while maintaining a low reverse salt flux and a higher water flux. The optimized NVC-FO membrane water flux can reach a maximum of 193.54L/(m²·h), and the reverse salt flux was 0.047mol/(m²·h) by using 1mol/L NaCl as the draw solution. It was found from the pressured forward osmosis experiments that the salt penetrating rupture pressure of these high-throughput NVC-FO membranes was between 200~1400Pa, confirming that reducing the monomer concentration would cause a significant decrease in the pressure resistance performance of the membranes. Although the pressure resistance of NVC-FO membrane needed to be improved, this research may provide a new idea for the construction of FO membrane with high desalination performance.

This work aimed to fabricate a superhydrophobic surface on paper substrate by roller coating with modified micro/nano-TiO₂, and evaluate the robustness, self-cleanability and hydrophobic performance of the coating paper surface. First, TiO₂ particles in microns and nanometers were hydrophobic modified by 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) and γ-aminopropy- ltriethoxysilane. Then, the modified micro/nano TiO₂ particles were coated on paper substrate surface. The chemical compositions of modified micro/nano TiO₂ were analyzed by FTIR and the surface structure of coating paper was characterized by SEM. The superhydrophobicity, robustness and self-cleaning property of the coating surface were evaluated by water contact angle, abrasion testing and self-cleaning testing. FTIR analysis of modified TiO₂ showed that the multiple stretching vibration peaks of C—F bond appeared between 1000~1500cm^-1, indicating that POTS was bound to the surface of TiO₂ through chemical bonds and the hydrophobic modification of TiO₂ was successful. SEM analysis of coating paper surface indicated that TiO₂ particles with micron and nanometer size were evenly distributed on the surface of paper substrate. The coating paper was a rough surface with micro-nano structure similar to that of lotus leaf. Water contact angle and rolling angle of coating paper surface were 153°±1.5° and 3°±0.5°, respectively, so water droplet was spherical on the coating surface and easily fall off, showing that coating paper surface was excellent superhydrophobic property. After the coating paper was immersed in water for 7d, the contact angle did not change significantly, indicating that the coating had good hydrophobic stability. After 10 cycles of abrasion testing on the coating paper surface, water contact angle and rolling angle of coating paper surface were 150° and 9°, respectively. It indicated that the mechanical friction did not cause significant damage to the chemical composition and rough structure of the coating paper surface, and the robustness of superhydrophobic surface was very well. Furthermore, self-cleaning testing showed that the coating paper surface was good self-cleaning and anti-fouling performance. The preparation process of superhydrophobic surface was simple and easy to be industrialized, and provided a novel convenience approach to constructing super-hydrophobic surface with excellent comprehensive performance.

As one of the most abundant reproducible organic aromatic polymers, bioconversion and valorization of lignin have considerable environmental, economic and social benefits. However, the lack of consolidation of the enzymatic assays of the ligninolytic enzymes has brought difficulties for the research on bioconversion of lignin. In this paper, we have compared and evaluated the sources, properties, and enzyme-substrate interaction mechanisms towards a few key ligninolytic enzymes including laccase (Lac), manganese peroxidase (MnP), lignin peroxidase (LiP), versatile peroxidase (VP) and dye-decoloration peroxidase (DyP). By discussions from the theory to applications of the most common assays including the ABTS method, 2,6-DMP method, VA method, Azure B method and other methods, the variety of substrates, assay conditions and scope of applications were thoroughly evaluated. In addition, solutions were provided for the major challenges existed in the enzymatic assays of ligninolytic enzymes, and this will offer valuable strategy for the bio-degradation of lignin and its value-added applications.

To achieve rapid start-up of methanogenesis of high-concentration organic wastewater, an EGSBBR system was used to treat influent COD concentration of 2000mg/L. Methanation start-up was realized after 34 days operation through gradually shortening hydraulic retention time and increasing ascending flow velocity of the reaction zone, and the corresponding COD removal efficiency increased from 67.5% to 94.2% with the influent organic loading rate up to 1.0kgCOD/(m³·d) and the maximum methane yield of the system being 582mL/d. The methane production was correlated with the change of effluent pH and VFA concentration, and the concentrations of polysaccharide and protein in sludge EPS increased significantly. High-throughput sequencing revealed that Methanothrix was the main abundant genus, indicating that methane was mainly formed by the decarboxylation of acetic acid under microaerobic conditions. This study offers a novel reference process for rapidly achieving methanogenesis of high-strength organic wastewater treatment.

With depletion of traditional fossil energies, comprehensive utilization of renewable resources such as lignocellulosic biomass has received increasing attention. For efficient utilization of lignocellulosic biomass, reducing structural recalcitrance of lignocellulosic biomass by physical, chemical or biological methods is a prerequisite. In our previous study, a new deep eutectic solvent (EaCl∶LAC) was developed with ethylamine hydrochloride as hydrogen bond acceptor and lactic acid as hydrogen bond donor. EaCl∶LAC is efficient in removing the hemicellulose from corncob. In this study, EaCl∶LAC was combined with a basic oxidant NaClO for the pretreatment of rice straw, resulting elevated hemicellulose and lignin removal percentages. After optimization, total reducing sugars in rice straw hydrolysate pretreated by EaCl∶LAC/NaClO was increased to 60.46g/L, with hemicellulose removal of 94.9% and delignification of 80.2%. Furthermore, rice straw hydrolysate was utilized for biobutanol fermentation by Clostridium saccharobutylicum DSM13864, achieving butanol titer of 10.16g/L^{and productivity of 0.22g/g_{total sugar} after 72 hours. This study provides a promising and effective method for pretreatment of lignocellulosic biomass, which can be facilely used in biofuel fermentation without external sugar and detoxification.}

The porous starch was prepared via a sol-gel method and supercritical CO₂ drying with cassava starch as raw material and water and ethanol as the mixed medium. The effects of water-alcohol ratio, gelatinization time, solid content, refrigeration time, ethanol replacement amount, and replacement time on the volume shrinkage and mass-loss rate of the starch were investigated. The morphology and pore structure of porous starch were characterized by the scanning electron microscope, specific surface area and pore size distribution analyzer, and X-ray diffractometer, and the formation mechanism of starch hydrogels and the influencing factors of the porous structure were studied. The results showed that when the ratio of water to alcohol was 19∶1, the solid content was 13%, the gelatinization time was 30min, the refrigeration time was 5d, the alcohol displacement amount was 5mL/g, and the replacement time was 30min, the volume shrinkage and the mass loss of the water gel were relatively small, the specific surface area of porous dry gel reached 122m²/ g, and the average pore size was 25.6nm. SEM and N₂ adsorption-desorption analysis showed that proper adjustment of solid content could improve the three-dimensional mesh density of the gel and increase the specific surface area and pore volume. XRD results indicated the starch molecules in hydrogels could form a crystallized network skeleton, which is conducive to maintaining the stability of water-alcohol gels of starch.

M-methylanisole is a dye intermediate. Its traditional synthesis method controls the mixing of reactants by low temperature, and the production efficiency is low. Improving the mixing of reactants through microreactors has important research value. The synthesis process of m-methylanisole with the aid of a microreactor was systematically studied, and it was found that m-cresol and sodium hydroxide reacted quickly to form sodium m-cresol in the reaction system. The oxyalkylation reaction between sodium m-cresol and dimethyl sulfate could be enhanced with the increase of the reaction temperature, and therefore the high temperature of 60—80℃ was more beneficial for the oxyalkylation reaction to compete with the hydrolysis of dimethyl sulfate. The effects of reactant flow ratio, metering ratio, concentration and other factors on the yield of m-methylanisole were investigated, and it was found that the microreactor to ensure the rapid and uniform mixing of the two-phase reactants was crucial for the success of fast and high temperature reaction. The relatively optimized experimental results showed that the yield of m-methylanisole reached more than 99% as the molar ratio of dimethyl sulfate to m-cresol was greater than 1.05 and 30% sodium hydroxide solution was used during the reaction.

This article provides a method to design a viscosity reducing agent, which builds a crude oil model through molecular simulation and calculates the type of monomer suitable for the viscosity reduction of the crude oil. Viscosity reducing agent was obtained by quaternary copolymerization of styrene with maleic anhydride, octadecyl methacrylate, and N-vinylpyrrolidone. The influence of various factors on the viscosity reduction was determined, and the optimal reaction conditions and monomer feeding ratio were obtained by measuring the viscosity reduction rate of crude oil, infrared spectrum and hydrogen spectrum. The results show that the feed ratio is 4∶13.5∶8∶3, and the reaction is performed at 80℃ for 8 hours. The amount of initiator is 1%(wt), the amount of chain transfer agent is 0.5% (mass fraction). The viscosity of crude oil can be reduced from 1100mPa·s (50℃) to 403mPa·s with a viscosity reduction rate of 63.3% by adding 0.3% (mass fraction) viscosity reducer. After testing the viscosity-temperature curve, it is found that the viscosity-reducing agent can effectively reduce the freezing point of crude oil from 38.5℃ to 33.2℃.The characterization by infrared spectrum and hydrogen spectrum indicates that it has the expected molecular structure.

Mercury emitted from industrial flue gas does great harm to human health and the ecological environment. Metal sulfide is a new type of high-efficiency mercury adsorbent, which has attracted extensive attention. This paper reviews the recent research progresses on mercury removal from flue gas by metal sulfides. The mercury removal performance of different metal sulfides was summarized, and the main influence factors were combed. Current studies suggest that metal sulfides can give excellent mercury removal performance even under complex reaction conditions. This paper also summarizes the mercury adsorption mechanism of metal sulfides and concludes that the adjustments of active sites and specific surface area of metal sulfides are the common methods to enhance the adsorption performance. Finally, the regeneration methods of metal sulfide are introduced. Based on the current research progress, future studies should focus on how to enhance the mercury removal performance of metal sulfides at high temperature, and meanwhile to achieve mercury desorption at low temperature to avoid the destruction of metal sulfide occurred in the high-temperature thermal desorption method.

It is the urgent to clear heavy metals from soil because the contamination of heavy metals in soil has the characteristics of complex polluting process, prominent threat and difficult to remediate. Electrokinetic-assisted phytoremediation (EKAPR) proposed to address the respective disadvantages of electrokinetic and phytoremediation, and synergistically to play the advantages of both. Meanwhile, it dedicated to solving the prominent problems such as contaminants incompletely cleaned of electrokinetic and remediation slowly and limited repair scope of phytoremediation. In this paper, the research processing, influence types, interaction characteristics and relationship, and enhanced mechanism of the remediate heavy metal contaminated soil of EKAPR were summarized. The review showed that there were both beneficial and unfavorable interaction effects between electrokinetic and plants in EKAPR system. In addition, they had many synergistic effects in terms of overcoming their limitations. The electric field type, electrode configuration, applied electric field strength, pH evolution and additives controlled the remediation process of EKAPR. Electrokinetic assisted can improve the phyto-accumulation of heavy metal and remediation efficiency of contaminated soil effectively by changing the spatial and morphological distribution of heavy metals, promoting nutrient absorption and stimulating rhizosphere secretion. Therefore, EKAPR was considered as a novel, green and sustainable innovation in-situ restoration technology of heavy metal, which had great development potential in realizing contaminated site remediation. The analysis revealed the less previous research works at present. Several technical problems and application challenges still existed. The key to overcome the difficult points and promote the practical application of EKAPR technology were that increasing study on the effect characteristics analysis and regulation of key variables of EKAPR, the variation cumulative characteristics and strengthening mechanism of plant nutrient and heavy metal distribution under electrokinetic assisted.

The high concentration of heavy metals in edible forest products and agricultural products, which results from metal pollution in soil is seriously dangerous to human health. Biochar, as a kind of easily and widely sourced adsorption material, can be available in soil remediation of heavy metal pollutants. The article reviews the preparation of biochar, selections and functions of modifier, modification methods, and the characteristics of modified biochar. Analysis methods and applications of Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray photoelectron spectroscopy(XPS) and specific surface area and pore size analyzers are introduced. The preparation method, repair mechanism and effect of modified biochar are analyzed, and the adsorption mechanism of biochar and modified biochar on heavy metals including surface adsorption, electrostatic interaction, ion exchange and coprecipitation are discussed. A large number of research results show that biochar has a significant effect on reducing the available content of heavy metals in soil, and is more efficient and stable after modification by acid/base, redox and adsorbent compound. Therefore, the goal of biochar modification is to improve the safety, efficiency, reusability, environmental friendliness, and to strengthen the capacity of heavy metal pollution remediation. Developing functional biochar and expanding the application of modified biochar are further research direction of modified biochar.

This study focused on the effect of C/N ratio on the removal efficiency of NH{}_{\mathrm{4}}^{+}-N and extracellular polymeric substance (EPS) during nitration process by using the sequencing batch reactor (SBR) to treat synthetic wastewater under four C/N ratio conditions (0, 5, 10, 15). Three-dimensional fluorescence spectroscopy (3D-EEM) coupled with fluorescence regional integration (FRI) was used to analyze the constituents of EPS. The results showed that the high removal efficiency of NH{}_{\mathrm{4}}^{+}-N was obtained and the ammoxidation rate was negatively correlated with the C/N ratio. When the C/N ratio increased from 0 to 15, the content of influent and effluent EPS and its components increased, the effect of C/N ratio on PS was significant, and the content of PS was accumulated during nitrification. According to fluorescence region integral (FRI) analysis, there was remarkable difference in the fluorescence response percentage of EPS for different C/N ratio , and region V(humic acid substance, 46%—57%) was the dominant fraction in EPS under different C/N conditions. In addition, the protein-like substance tyrosine and tryptophan, and soluble microbial by-product were utilized during nitrification.

Temperature is one of the most critical operational parameters for biological purification filter. In order to investigate the removal efficiency of ammonia, iron and manganese in the process of water temperature dropping from about 25℃ to 6℃, the biological purification filter was used to treat the simulated groundwater containing ammonia, iron and manganese. The results showed that the concentration of ammonia, total iron and manganese in the effluent was lower than 0.15mg/L, 0.1mg/L and 0.05mg/L, respectively, which were all lower than the national standards. Total iron and manganese in the effluent were not adversely affected by the decrease of water temperature, but ammonia in the effluent gradually increased from about 0.02mg/L to about 0.12mg/L. Further analysis showed that iron was mainly removed in 0—0.4m of the filter layer, and iron removal was not affected by the variation of water temperature. Ammonia and manganese were mainly removed in 0—0.8m of the filter bed, and their concentrations along the filter bed obviously increased with the decrease of water temperature. Biological ammonia and manganese removal were observed to follow a first-order kinetic reaction. When the water temperature was 24.6℃, 15.3℃ and 6.7℃, the kinetic constants k were 0.154min^-1, 0.186min^-1; 0.143min^-1, 0.175min^-1; 0.103min^-1 and 0.163min^-1, respectively, and the half reaction times t_1/2 were 4.51min, 3.72min; 4.83min, 3.96min; 6.72min and 4.24min, respectively. With the decrease of water temperature, the removal efficiency of ammonia and manganese was obviously and adversely affected.

Acid orange Ⅱ, auramine O, and their composites were treated by coagulation-photocatalysis. The optimum coagulant dosage and pH were determined. Decolorization performance of the combined technology (coagulation-photocatalysis) was compared with that of the single treatment method. The effects of pH value, photocatalytic time, salt content and turbidity on decolorization efficiency were explored. The results showed that the optimum decolorization conditions varied by specific dye. For the color removal of composite dye (acid orange Ⅱ-auramine O), the highest decolorization efficiency was 78.92% with 6 of pH, 920mg/L of coagulant, and 120min of photocatalytic degradation time. Decolorization performance of coagulation-photocatalysis was obviously better than that of coagulation or photocatalysis, which was closely related to the molecular structure of the tested dye. The high ion strength and turbidity could reduce the adsorption neutralization and adsorption bridging capacity of coagulants. Besides, the surface effect of TiO₂ was also inhibited, therefore, the decolorization performance of coagulation-photocatalysis was reduced. Decolorization efficiency was reduced by 36.87% when salt content was 1200mg/L. Additionally, decolorization efficiency was reduced by 19.85% when turbidity was 412.2NTU.

Advanced oxidation processes on aniline simulated wastewater treatment have received considerable studies to eliminate organic pollutants, but such techniques have rarely been employed to solve the problem of high salinity, high chromaticity and refractory COD of aniline wastewater in petrochemical enterprises. In this study, in situ degradation experiments (1—2m³/h) on aniline wastewater by TiO₂/UV-H₂O₂ were carried out. The degradation effects of aniline wastewater were examined in TiO₂/UV system, H₂O₂ oxidation system, and a combination system of TiO₂/UV and H₂O₂. An optimal treatment process for aniline wastewater was proposed and its operational costs were also evaluated. It was observed that the application of TiO₂/UV and H₂O₂ alone had relatively low decolorization rate and COD removal rate for aniline wastewater, whereas the decolorization rate and COD removal rate can reach over 95% by TiO₂/UV-H₂O₂ synergistic oxidation. H₂O₂ contributes to a predominant oxidative degradation in the synergistic oxidation system with a common total dosage of 1%~2%. Acidic conditions favored the degradation of aniline-containing wastewater, especially pH=3.8~4.2. After a period of synergistic oxidation by TiO₂/UV-H₂O₂, the UV light was turned off and the intermediate compounds in the system could be further mineralized to CO₂ by residual H₂O₂. COD and chromaticity in the effluent were below 60mg/L and 20 times, respectively, and the operational cost was 18.44 kW·h/m³, much lower than the reported value. So, TiO₂/UV-H₂O₂ seems to be significantly feasible and economical for the mineralization of aniline wastewater.

The extraction of phenol from coal gasification wastewater with tributyl phosphate (TBP)-n-octanol was studied. The effects of complexing agent concentration and reaction temperature on the extraction distribution coefficientwere studied to determine the enthalpy of complex structures and reactions. Finally, the distribution coefficient mathematical model of phenol extraction was establishedbased onliquid-liquid extraction models, and the accuracy of the model was verified by using coal gasification wastewater as an experimental sample.The results show that when the volume fraction of TBP increased from 10% to 50%, the partition coefficient increased from 17.6 to 61.4, when the temperature increased from 30℃ to 70℃, the partition coefficient decreased from 42.9 to 34.7; the concentration affected the partition coefficient model and the average relative error was controlled at 1.14%; the temperature affected the partition coefficient model and the average relative error was controlled at 0.87%. Through the comparison of model estimates and actual experimental values, it can be considered that the extraction partition coefficient model has high reliability in predicting the coal gasification wastewater extraction partition coefficient.