From the perspectives of the new global technological revolution and industrial transformation, the transition of China’s chemical industry production mode, the realization of “carbon neutrality”, and the agricultural industrialization, this work expounded the meaning and significance of green bio-manufacturing, and analyzed China’s bio-manufacturing industry status and its strategic demand. It was pointed out that although it bears a late start, bio-manufacturing had been fast developing in the past years, and achieved considerable progress on fermentation, biobased products and bioenergy, forming a solid framework for future development. At the same time, shortcomings such as lack of key and core technologies, and forward-looking technologies, behindhand R&D of key and core equipment, low marketization, and insufficient competitiveness, were emerging. Hence, related proposition was made on the future development directions and pathway for the industry, including the promotion of diversification of raw materials, and establishment of an advanced biological manufacturing technology system. The article pointed out that it was of great strategic significance for China’s taking a new path of industrialization, and its economy and society’s renewable development, to speed up breakthroughs in technology and equipment from genomes to industrial synthesis, to support the green production of key products such as bio-based chemicals, bio-based materials, and bioenergy, and to promote “agricultural industrialization, industrial greenization, and industrial internationalization” through bio-manufacturing.

Chiral alcohols are important and versatile building blocks for the preparation of a variety of pharmaceuticals and fine chemicals. It is of great value to develop green production technologies for chiral alcohols using carbonyl reductase as the biocatalyst, which attracts widely concentration around the world. This article reviews the discovery and classification, the mechanism of activity and stereoselectivity, enzyme screening and molecular modification technologies, cofactor regeneration, as well as the biosynthesis of pharmaceutical intermediates and fine chemicals catalyzed by stereoselective carbonyl reductases. The development in enzymatic production of anticholesterol drugs, antibiotics, antineoplastics, antidepressants, antiepileptics, etc. is investigated. The review contributes to the theoretical and technical guidance for the development of stereoselective carbonyl reductase biocatalysts and the biosynthesis of chiral pharmaceutical intermediates and fine chemicals.

Biobutanol (n-butanol) is an important bulk chemical and biofuel candidate, which can be obtained via acetone-butanol-ethanol (ABE) fermentation from biomass. Because of the low concentration of solvents products, the conventional biobutanol separation is costly and energy-intensive. To overcome the above limitation, recently, alternative separation techniques are emerged. In this review, the current advances of the potential alternative separation techniques, including the vapor-liquid equilibrium, solvents polarity-based techniques and membrane-based separation for biobutanol recovery are summarized, followed by discussing the multi-stage cascade separations. Facing the generation of commercial guide biobutanol production, the trends for ABE distillation is also included. With the improvement of separation technology and the development of biorefinery process, the overall cost of biobutanol production can be decreased, which would further improve the competitiveness of biobutanol process in terms of commercialization.

Halophilic microorganisms including halophilic bacteria, archaea and algae, can be grown under high salt concentration conditions. Among them, the mild halophiles tolerating 30—150g/L NaCl are valuable for application purposes. Many halophiles can grow rapidly in seawater under alkali conditions in minimal media, and they are strong candidates as chassis for industrial purposes. Recently, more and more molecular tools and approaches have been developed for manipulating halophiles, resulting in a longer product pipeline including biopolymers, proteins, chemicals, amino acids and cosmetic ingredients. The use of synthetic biology methods allows controllable morphology changes of halophiles for more intracellular product formation and downstream separation of the cell. Based on the recent progresses of halophiles, especially halophilic bacteria, we propose the halophilic bacteria based “next generation industrial biotechnology” (NGIB), which allows microbial fermentations to be conducted under open unsterile and continuous processes using seawater as a medium to save fresh water and energy for sterilization. Halophilic bacteria are more robust than other traditional microbial chassis. They can be full-automatically controlled under continuous way to maintain consistent growth conditions. The unsterile processes significantly reduce the process complexity and equipment cost, further enhancing the product competitiveness. Co-production of intracellular and extracellular molecules increases the economic benefits of the NGIB.

Carotenoids have brilliant colors and strong antioxidant activity, which not only endow these compounds with high commercial value, but also accelerate the construction process for building efficient biosynthetic pathways in heterogeneous chassis. Carotenoids have become an ideal object to develop irrational design strategy. Here we critically review recent advances about carotenoid biosynthesis via irrational design strategies on pathway construction by parts optimization, modular compatibility, multidimensional regulation etc., as well as chassis evolution by DNA mutation and adaptive evolution. These strategies aims to break the bottleneck of carotenoid biosynthesis through improving the supply and utilization of precursor GGPP as well as relieving the stress from carotenoid accumulation on microbiological chassis. Based on the demand of employing unconventional chassis and expanding carotenoid kingdom, we also propose the development of the construction strategies for carotenoid microbiological cell factories towards the automation and intellectualization.

Plant natural products possess diverse structures, physiological activities and functions. The use of microbial cell factories to produce plant natural products with scarce sources and difficult to obtain has the advantages of economic viability and environmental friendliness. This paper systematically introduces the biosynthetic pathways and key enzymes of terpenes, flavonoids and alkaloids, and expounds the decipher and reconstruction methods of their biosynthesis pathways including transcriptomics and isozyme mining. It is pointed out that enzyme engineering, dynamic control, metabolic compartmentation and metabolic network rebalance are effective strategies to increase the metabolic flux of exogenous pathways, inhibit by-product synthesis, reduce product toxicity and strain metabolic burden, and improve the synthesis ability of target products. Suggestions are put forward to further improve the production efficiency of microbial cell factories, such as analyzing the catalytic specific mechanism of plant enzymes in microorganisms, and developing efficient assembly methods for exogenous pathways.

D-amino acid oxidase is a class of flavine adenine dinucleotide containing oxidordeuctase that catalyzes the oxidative dehydrogenation of D-amino acids, which results in corresponding α-keto acids, hydrogen peroxide, and ammonia. D-amino acid oxidases are widely distributed in nature, mainly found in multiple eukaryotic and few prokaryotic organisms. As a classic biocatalyst, D-amino acid oxidases have played important roles in the synthesis of various medicine, pesticides as well as fine chemicals, owing to the mild reaction conditions, broad substrate spectrum and excellent enantioselectivity. Herein, we review the structural characteristics, catalytic mechanism, and protein engineering of D-amino acid oxidase, as well as its application in biocatalysis. Different molecular modification strategies for the engineering of D-amino acid oxidase and the representative achievements are further described. The preparation of 7-aminocephalosporanic acid,chiral amino acids,amines and α-keto acids by using D-amino acid oxidase is also summarized. Finally, the current problems in the biocatalytic application of this enzyme are discussed. The subsequent research could focus on the mining and engineering of novel D-amino acid oxidase. Based on the molecular mechanism of enantioselectivity and substrate recognition, the rational design could be applied to modify the catalytic performance. Furthermore, the newly obtained enzymes could be utilized to construct novel biosynthetic pathways for functional chemicals.

Polyketides have wide range of medicinal activities and extremely high economic value, but how to synthesize polyketides efficiently, economically, green, and environmentally friendly remains a problem that needs to be solved urgently. With the development of synthetic biology, new technologies and strategies are constantly being used in the biomanufacturing of polyketides. This article introduces the key enzymes, precursors, and metabolic pathways in the biomanufacturing of polyketides, and analyzes utilizing the CRISPR technology and post-translational modification metabolic engineering to optimize the metabolic regulatory network, remolding and optimizing metabolic pathways by replacing and optimizing promoters, and improving the efficiency of polyketide biomanufacturing and the utilization of carbon sources by exploring strategies such as constructing simple and efficient heterologous expression systems. In addition, the latest research progresses of synthetic biology in erythromycin, abamectin, spinosyn are summarized. Finally, the problems faced by the biosynthesis of polyketides and possible solutions, such as balancing primary metabolism and secondary metabolism, constructing new and dominant chassis cells, and redesigning and remolding metabolic networks are prospected.

Rare ginsenosides are the most important active constituents of ginseng. However, they either contribute to an extremely low proportion of total ginsenosides or do not exist until being transformed in human intestines. Thus, this review summarizes the structure-function relationship and transformation strategies of ginsenosides, focusing on the latest progress of microbial and enzymatic transformation strategies, including transformation of ginsenosides using probiotic and edible-medicinal fungi for the production of functional food, as well as the selection and combination of glycosidases for improving transformation efficiency and productivity of total ginsenosides. It also discusses in depth the effects of genetic engineering, solvent engineering and enzyme immobilization on the transformation efficiency and productivity, and analyzes the potential application value of protein engineering and synthetic biology in improving the catalytic activities and paving the way for large-scale production of rare ginsenosides.

Global transcription machinery engineering is an important technical method to reprogram gene transcription to obtain new cell phenotypes. Through DNA recombination, error-prone PCR and other techniques, multiple rounds of mutation modification of transcription elements in cells are carried out to change the conversion efficiency of RNA polymerase and the affinity for promoters is discussed. They change the transcription of cells on the whole genomic level, thereby evolving a cell phenotype that meets actual needs. It is indicated that global transcription machinery engineering can not only rapidly optimize metabolic pathways and increase the yield of target compounds, but also improve strain tolerances. These advantages have been successfully applied to the construction of microbial cell factories for various compounds production.

The production of bulk chemicals and natural products from renewable feedstocks by microbial cell factories is promising and sustainable. Tailoring natural or synthetic pathways in microbial hosts provides a foundation for constructing microbial cell factories. However, tailoring pathways in microbial hosts always causes metabolic disturbance, which reduces the suitability as well as the performance of microbial cell factories. The performance of microbial cell factories can be enhanced by reinforcing suitability between different metabolic pathways or by improving suitability between metabolic pathways and microbial cells. In this review, we discussed recent studies about reinforcing and balancing the metabolic flux of synthetic pathway, limiting cross-talk between the engineered pathways and the cellular milieu, and improving the suitability of metabolic pathway and microbial cell, which provided an opportunity to enhance the performance of microbial cell factories. Furthermore, we proposed future research directions to develop multidimensional regulation strategy for reprogramming the suitability of metabolic pathways at the cellular level and enhancing the suitability of microbial cells to metabolite.

Collagen exists in all tissues and organs. Compared with animal collagen, recombinant collagen has a more single component, higher safety, and more controllable production process. This review briefly introduces the construction of different expression systems of recombinant collagen, including the expression systems of animals, plants, and microorganisms, and their advantages and disadvantages are compared. The regulation of different fermentation parameters affecting the expression of the product in the microbial system, the separation and purification process of the product, and the application of recombinant collagen in the medical field were introduced emphatically. It is pointed out that the microbial fermentation system has a lower cost, simple operation, and easier to expand production than the animal and plant system. Temperature, pH, dissolved oxygen, glucose, and acetic acid concentration affect the protein expression in Escherichia coli fermentation. In yeast fermentation, the addition amount of methanol, temperature, pH, and dissolved oxygen are the main influencing parameters. Microbial fermentation systems need to obtain high purity products through different crude and precision technologies. Meanwhile, recombinant collagen plays an important role in the field of biomedicine.

Oily sludge is a complex composition system containing oil, solid particles, heavy metals, and water, which is produced in the process of petroleum production and processing. It has been included in the list of hazardous wastes due to its highly stable and difficult for treatment. There is a large amount of oily sludge in China, and untreated external discharge will cause serious environmental pollution. The oil production and processing enterprises have invested a lot of resources in the treatment of oily sludge, and have developed several types of technologies, such as thermochemical cleaning, pyrolysis, temperature and pressure conditioning, microbial treatment, etc. Among them, thermochemical cleaning has the advantages of high oil recovery rate, low residue oil content rate, low cost, etc. This paper summarizes the domestic and international oily sludge treatment standards, and describes the research progress of thermochemical cleaning technology with focusing on the influence of detergent types and concentrations, hot washing temperature, hot washing time, mixing speed, liquid-solid ratio and other factors on the treatment efficiency of oily sludge. The future development direction of thermochemical cleaning technology is proposed to provide reference for the development of thermochemical cleaning technology for oily sludge treatment.

The styrene-maleic anhydride copolymer (SMA)/chlorinated polyvinyl chloride (CPVC) blend ultrafiltration membranes was prepared bynon-solvent induced phase separation (NIPS). The effects of different solvent (DMAc) content in coagulation bath on the degree of anhydride group segregation of membranes surface, microstructure, hydrophilicity, water flux, rejection and anti-pollution of the ultrafiltration membrane were discussed. The results showed that the increase of DMAc content in the coagulation bath inhibited the degree of segregation of anhydride on the membrane surface, resulting in the decrease of hydrophilicity. At the same time, the decrease of the diffusion rate between DMAc and water molecules in the casting solution caused delayed phase separation, which made the pore size of the membrane surface smaller and the distribution narrower. When the mass ratio of DMAc was 3%, the BSA retention rate of ultrafiltration membrane increased to 98.10% with the flux recovery rate of 96.82%, and the irreversible contamination rate decreased to 3.77%, indicating that the appropriate solvent in the coagulation bath could further improve the anti-pollution performance of the ultrafiltration membrane.

The air-liquid interface corrosion widely exists in daily industries. Because of the instability of the air-liquid interface, most research on the interface corrosion is aimed at analyzing the cumulative corrosion effect near the changing interface position for a period of time. In experimenting, a fixed volume bubble was injected into the under surface of copper sample to maintain the stability of the air-liquid interface and the constant ion concentration. By comparing the corrosion data of interface/no-interface samples in different concentration of NaCl solution, the interface corrosion mechanism was proposed. The results show that the corrosion potential and corrosion current of the copper with air-liquid interface are increased. At the air-liquid interface, the corrosion current of the sample is significantly increased by the micro-interface energy difference corrosion and macro-oxygen concentration difference battery corrosion, and therefore the corrosion rates of samples with interface are bigger than those without interface in the whole concentration range. Meanwhile a clearly visible interface corrosion line on samples is left. The interface corrosion rate is extracted by the analysis of experimental data. The results show that the total corrosion rate increases firstly and then decreases, but the interface corrosion rate monotonically increases with the increase of solution concentration.

Electrostatic spray is widely used in industry, such as electrostatic spraying, electrostatic atomizing combustion, electrostatic atomization dust removal, etc. The application effect is closely related to spray charge characteristics. In order to obtain a better charge effect, the influence of the induced current on the true charge current of the droplet during the corona charging process was explored. The changes of spray charge-to-mass ratio, charge decay and droplet size were studied by changing the charge voltage, electrode spacing, electrode ring diameter and liquid flow rate. The results showed that the corona charging process is unstable but can obtain better charge effect. The charge-to-mass ratio of droplet decrease first then increases as the increase of charge voltage. It increases first and then decreases with the increase of the electrode ring diameter, and increases with the increase of the electrode spacing at the same voltage. The best charging effect is that the electrode ring diameter is 80mm and the electrode spacing is 40mm. When the droplet was charged, the charge amount would vary with the transport distance. The corona charge decayed faster than inductive charge at the same distance. Charged droplet could reduce the surface tension and the particle size of the droplet. As the charge capacity of the droplet increases, the droplet size decreases.

In view of the current situation of high energy consumption and environmental pollution for the metal cleaning and drying processes in industrial filed, a closed heat pump drying system with a direct series auxiliary condenser was established. The effect of cooling water flow rate through auxiliary condenser on the operating parameters of the system was experimentally studied. These operating parameters included operating conditions of the system, heating/cooling capacity, power consumption, COP (coefficient of performance), MER (moisture extraction rates) and SMER (specific moisture extraction rates). The results showed that when the cooling water flow rate was 30.6kg/h, the condenser outlet air temperature reached 72.8℃. And with the increase of cooling water flow rate of auxiliary condenser, the heating/cooling capacity, power consumption, condenser outlet temperature and MER all decreased, while COP was remained at 5.6. The highest MER and SMER were 3.80kg/h and 1.44kg/(kW·h), respectively. The change trends of MER and SMER were opposite as the increase of cooling water flow rate of auxiliary condenser, so the influence of cooling water flow rate needs to be comprehensively considered in practical production. Besides, under the experimental conditions, the maximum cooling water outlet temperature was 65.2℃, and hot water for industrial production could be provided and energy could be recovered. The research results can provide new ideas and references for the application of closed heat pump drying system in the metal cleaning and drying processes and its energy conservation.

In order to improve the performance of the CO₂ transcritical heat pump heating system, a heat recovery system with secondary air supply for two-stage compression and double gas cooler is proposed. Through the establishment of the thermodynamic model, the impact of various factors on the energy efficiency of the system is analyzed combined with the other three CO₂ heat pump systems and the R134a single-stage compression regenerative system. In addition, the total investment situation of each system in different cities during the operating cycle is studied based on typical annual meteorological parameters by an economic evaluation model, which comprehensively considers the initial investment cost and annual operating cost. The results show that the heat recovery system with secondary air supply for two-stage compression and double gas cooler is the optimal system scheme, which has the highest COP_h and exceeds that of R134a single-stage compression regenerative system. When the ambient temperature is 0℃ and the temperature of outlet/return water is 65℃/40℃, the theoretical COP_h can reach 2.58, which is 9.1% higher than that of the R134a system, and 22.5% higher than that of CO₂ single-stage compression system, and the compressor discharge temperature doesn't exceed the existing temperature limit. In the selected sampling cities, the total investment cost of all heat pump systems during the operating cycle is the lowest in Shanghai and the highest in Shenyang, which shows that it is greatly affected by the climate region. Due to the high cost of the CO₂ compressor, the total investment cost of the CO₂ heat pump system is higher than that of the R134a system. With the improvement of CO₂ heat pump technology and the expansion of production scale, when the cost of the compressor is reduced by 80%, the total investment cost of the heat recovery system with secondary air supply for two-stage compression and double gas cooler will be lower than that of R134a system.

In order to explore the Ledinegg instability of the micro-channels of different corrugated wall surfaces, computer numerical control was used to process three types of micro-channels of wall surfaces, namely sine wave, triangle wave and ordinary smooth micro-channels. R141b was used as the experimental working medium to conduct the flow heat transfer experiments under the conditions of pressure of 40—80kPa, heat flux of 13.281—22.138kW/m² and inlet temperature of 33℃. The experimental results showed that the negative slope of pressure drop-flow curve in triangular ripple micro channel has the lowest slope, and the mass flux at the onset of flow instability (OFI) is the largest, and Ledinegg instability is most likely to occur, while the normal smooth micro channel is the opposite. In addition, with the increase of heat flux, the slope of the negative slope region of the pressure drop-flow curve of the micro channel decreases, and the mass flux at OFI increases, indicating that the increase of heat flux will increase the instability of the system. With the increase of system pressure, the negative slope area of pressure drop-flow curve of the micro channel became gentler, while the mass flux at OFI did not change much, indicating that increasing system pressure was beneficial to the stability of the system.

The pyrolysis characteristics of Naomaohu coal were studied in a moving bed reactor with internals consisting of multi-stage baffles and multi-stage gas outlet lines, and compared with the coal pyrolysis behavior in conventional fixed bed reactor. The effects of heat transfer rate and pyrolysis temperature on products yield, pyrolysis gas composition, and tar composition and quality were investigated in the two reactors. The results showed that the heating time of coal particles in the moving bed reactor with internals was shortened by more than 60% than that of the fixed bed ne during pyrolysis at 450℃, and the internals can significantly enhanced the heat transfer rate of the particles in reactor. With increasing pyrolysis temperature, the ratio of C₂H₄/C₂H₆ and C₃H₆/C₃H₈ in pyrolysis gas increased, the secondary reaction of volatiles increased, but the degree of cracking was lower than that of fixed bed reactor. The tar yield in the moving bed reactor with internals increased first and then decreased with increasing temperature, and reached a maximum mass ratio of 10.8% at 550℃, which was about 28.6% higher than that of the fixed bed one. When the pyrolysis temperature was higher, the content of asphaltene components in the tar produced by the moving bed reactor was lower. At 750℃, the mass ratio of light components in tar reached 85.17% and the content of aliphatic hydrocarbons decreased to 28.00%. Compared with the fixed bed reactor, the role of internals (multi-stage baffles and gas outlet lines) in regulating the pyrolysis reaction of Naomaohu coal and improving the yield and quality of pyrolysis tar was revealed in the moving bed reactor.

The gasification of coal produced a large number of slags, which results in serious environmental problems. Hence, the comprehensive utilization of gasification slag is urgent. In this paper, the characteristics of different density components in the coal gasification slag were analyzed systematically, which indicates that the separation of carbon and ash was the premise and foundation for the utilization of coal gasification slag. A method of carbon-ash separation based on the apparent density difference is proposed. Water-only cyclone was used as separation equipment and single-factor tests were carried out to determine the main process parameters on the separation effect of carbon and ash. It proved the feasibility of the water-only cyclone for >0.074mm carbon-ash separation. By means of Box-Behnken Design, the quantitative relationship between the cone angle of the water-only cyclone, the apex diameter, the vortex finder depth and the ash content, the yield, the comprehensive efficiency of separation is analyzed, which provides data support for the prediction of carbon-ash separation effect and the selection of cyclone structure parameters. The results provide guidance for the utilization of coal gasification slag.

High pure alcohol is widely used in food, medicine, petrochemical, etc. The common method for the preparation of high concentration of alcohol is alcohol five-column distillation, but the traditional distillation process is often accompanied by high energy consumption and high cost. To solve the above problems, a new distillation-adsorption-membrane separation coupling process was proposed in this study to efficiently obtain high concentration alcohol from ethanol fermentation broth. Aspen Plus process simulation software was used to investigate the distillation-adsorption-membrane separation coupling process, and the sensitivity analysis tool was used to optimize the parameters of the distillation column. The results showed that the mass fraction of ethanol reached 99.2% and the ethanol recovery was 65.6% when the number of trays in the distillation column was 37, the reflux ratio was 9, the feeding position was the 35th tray, the adsorbent was natural zeolite and the membrane was separated by polyvinylidene fluoride pervaporation membrane. Compared with the traditional five-column distillation method, high pure alcohol can be obtained with low energy consumption and equipment cost. Meanwhile, the space utilization rate is also reduced. This study reveals that distillation-adsorption-membrane separation coupling process has a good industrial prospect.

Lignite in eastern area of Inner Mongolia accounts for 83% of China’s lignite reserves and is also the main energy source in this area. Low temperature pyrolysis of coal has the advantages of mild process conditions, extensive product usage and high profitability, which is the main method used for lignite processing. Due to low lump coal ratio, high moisture content in lignite, serious fragments during thermal processing, and the current environmental protection policy becoming more and more strict, low lignite utilization rate, unqualified pollution discharge and discontinuous operation exist in lignite pyrolysis plants. This article introduces lignite pyrolysis technologies that have come into industrial application in eastern area of Inner Mongolia as follows: low-rank coal conversion technology (LCC), localizing continuous pyrolysis technology (LCP), belt-furnace lignite upgrade technology, GF-1 lignite upgrade technology, SJ low-temperature drying furnace technology and gas-coal cross-flow pyrolysis technology, the operation state, advantages and drawbacks of which are also presented. By comparing the raw material requirements, heat transfer modes, coke quenching methods, heat utilization efficiency and product properties of these technologies, we propose that the future development direction should be raw material optimization, heat optimization, product diversification and waste reclamation, to achieve the industrial application of lignite pyrolysis in eastern area of Inner Mongolia, China.

Compared with solid-liquid phase change materials, solid-solid phase change materials (SS-PCMs) have received less attention. SS-PCMs is a type of phase change material with development potential as they possess the advantages of high energy storage density, non-toxic and low corrosion, no liquid generated and small volume change during phase change, low phase separation, and low supercooling. Based on the current research status of SS-PCMs, this paper summarized the research progress of several important SS-PCMs such as polyol SS-PCMs, polymer SS-PCMs and inorganic salts SS-PCMs in recent years. The classification of SS-PCMs and the performance, heat storage mechanism, advantages and disadvantages of various SS-PCMs were briefly described. Meanwhile, the basic principles of selecting solid-solid phase change materials for application were introduced, and the modification studies on the problems of low thermal conductivity, large supercooling and poor stability of phase change materials were reviewed. The application research of SS-PCMs was also briefly reviewed. Finally, the article pointed out that future research should focus on solving the defects of synthesized SS-PCMs, developing multi-functional SS-PCMs and making breakthroughs in the practical application of SS-PCMs.

The electrocatalytic reduction of CO₂ to valuable fuels and chemicals has great potential in mitigating global warming and effectively storing renewable energy, which has received extensive attention in recent years. Herein, first of all, this review briefly describes the research results of the reaction pathways of CO₂ electrochemical reduction to different products in aqueous solutions. Currently, the generation pathways of simple C₁ products are relatively clear, but the reaction pathways for multi-carbon hydrocarbons and alcohols generation are still unclear, which needs further exploration. Then, the recent advances of metal-based electrocatalytic materials for CO₂ electrochemical reduction is described. Focusing on product selectivity, catalytic activity and stability, this review presents the research status of nanostructured metals, metal alloys, metal oxides, metal complexes, and single atomic metal materials. Finally, the prospect of electrocatalytic CO₂ reduction is proposed. It points out that continuously optimizing the performance of electrocatalytic materials is one of the main directions in future research, especially the single atomic catalysts, which are expected to replace Au, Ag and other precious metals, as well as the copper-based materials that can efficiently produce multi-carbon products. Meanwhile, the in-depth exploration of the mechanism of CO₂ electrochemical reduction reactions based on more accurate theoretical calculations combined with in-situ spectral characterizations will greatly promote the development of highly efficient electrocatalytic materials.

Compared with traditional fiber preparation methods such as mechanical drawing, electrospinning is simpler and more economical and therefore has a wide range of applications in the areas of fuel cell, metal-air battery, water electrolysis device, etc. This article first introduced the working principle, influencing factors and development status of the electrospinning technology. Then, the research progress of electrospinning in the preparation of electrocatalysts and carrier material was summarized, including: ①For alkaline solutions, transition metal derivatives and metal-carbon nanofibers prepared by electrospinning have shown excellent electrocatalytic performance and considerable economic benefits under various electrochemical reactions; ②In water electrolysis reactions, the iridium-based catalysts prepared by electrospinning can exhibit a uniform one-dimensional nanostructure, which has higher specific surface area and better dispersibility and thus could provide excellent catalytic activity; ③In the acidic oxygen reduction and oxygen evolution reactions, the electrospun tin antimony oxide (ATO) carrier has shown good electrical conductivity, which not only provides a better electron transfer structure and catalytic active site for the catalyst, but also plays a role in structural protection. Thus, it can improve the catalytic activity and stability. Then, this article summarized the advantages and limitations of preparing catalysts or their carriers by electrospinning. It was found that the one-dimensional nano-catalyst has excellent fiber morphology compared to traditional ones, which could provide larger specific surface area and lower mass transfer resistance. Thus, it can effectively solve the problems of traditional metal catalyst particles, such as the low dispersion and low activity. Finally, in order to further improve the oxygen evolution catalytic performance of electrospinning catalysts and achieve the controllability of electrospinning fiber arrangement structures, some suggestions and prospects were proposed for the future development of electrospinning technology.

Photoelectrocatalytic(PEC) water splitting offers a promising approach to convert solar energy into hydrogen energy. The photoelectrode, as the core of the PEC water splitting system, determines the photo-conversion efficiency. Among various semiconductors, zinc oxide (ZnO) has attracted much attention owing to its low onset potential, high charge mobility and low cost. However, ZnO possesses a wide band gap, the serious recombination of electron-hole pairs and sluggish kinetics of the oxygen evolution reaction, which greatly restrict their photo-conversion efficiency. In this review, the recent advances in the fabrication of ZnO-based photoanode and its PEC performances were discussed. Firstly, the effect of the morphology and intrinsic defect in ZnO semiconductor on the PEC properties were elaborated. Then, several strategies that can be employed for construction the surface/interface of ZnO-based semiconductors were discussed, including element doping, quantum dot sensitization, noble metal deposition, heterostructure and coupling the cocatalysts. The effects of different strategies on the PEC properties of ZnO-based semiconductors were also discussed. Finally, the future research directions of ZnO-based semiconductors were prospected at five aspects including surface modification of ZnO, constructing the interface of the composite semiconductor at atom level, replacing noble metal Au, Ag and Pt nanoparticles with inexpensive bimetallic or polymetallic nanoparticles, fabrication of the high efficient cocatalyst and introducing interlayers such as hole-storage layers or electron-blocking layers.

The application of perovskite in catalysts has received extensive attention, due to its stable structure and special physical and chemical properties. In this paper, the research progress in strengthening the activity, anti-toxicity, stability and selectivity of La-based perovskite catalysts with different methods is reviewed. The effects of the structure, surface parameters, active oxygen and low-temperature reducibility of La-based perovskite catalysts on the conversion efficiency of volatile organic compounds were analyzed. The optimization of the perovskite synthesis, and the preparation of supported perovskite and doped perovskite to improve the performance of the La-based perovskite catalyst are also introduced. And the future research directions of the La-based perovskite catalysts are prospected, which are to prepare efficient catalysts by doping non-metal elements and combining multiple methods, to integrate catalytic combustion and photocatalytic oxidation for volatile organic compounds conversion, and to further use experiments and simulations in seeking the ideal catalyst for the catalytic oxidation of volatile organic compound mixtures to meet industrial needs.

CO₂ is one of the main greenhouse gases, and the cycloaddition of CO₂ with epoxides can produce various cyclic carbonates, which is a relative green, economical and feasible way for CO₂ capture and utilization. Using porous hypercrosslinked polymers immobilized ionic liquids (HCPs-ILs) to catalyze the CO₂ cycloaddition reaction does not require solvents, metals and co-catalysts. In this review, we summarized the recent research progress on CO₂ cycloaddition catalyzed by HCPs-ILs, as well as the characteristics of three methods for preparing hypercrosslinked polymer immobilized ionic liquids, namely ionic monomer self-polymerization/copolymerization or crosslinking method, one-step method of simultaneous formation of ions and crosslinking, and post modification method. The problems that are not conducive to the application of “CO₂ chemical industry” such as low ionic density, insufficient catalytic efficiency, and high preparation cost were also analyzed. Finally, we pointed out that in order to realize the rapid catalysis of the cycloaddition reaction of CO₂ with epoxides under normal pressure, theoretical and technical researches should be strengthened from the aspects of increasing ionic density, regulating the surface activation functional groups and ionic microenvironment, and reducing the preparation costs.

Al-FDU-12 mesoporous materials with different silicon-to-aluminum atomic ratios (Si/Al=50, 40, 30, 20 and 10) were synthesized by in-situ synthesis, and the catalysts NiMo/Al-FDU-12 were prepared by further impregnating nickel and molybdenum active metals. The Al-FDU-12 and catalysts were characterized by means of small-angle XRD, wide-angle XRD, N₂ adsorption and desorption, SEM, TEM, UV and other characterization means. The hydrodesulfurization (HDS) performances of the NiMo/Al-FDU-12 with different Si and Al ratios were also evaluated. It showed that FDU-12 with high pore size, volume and surface area would lead to the high dispersion degree of active metals. The hydrodesulfurization and denitrification performances of NiMo/Al-FDU-12 catalyst were improved after Al modification. As the reaction conditions were: temperature of 350℃, hydrogen and oil volume ratio of 600, pressure of 5.0MPa, WHSV of 1.0h^-1, Si and Al atomic ratio of 20, the catalyst showed the highest hydrodesulfurization and denitrification activity. The desulfurization and denitrification rate could reach 98.9% and 95.3%, respectively. Under similar reaction conditions, the industrial catalyst presented lower hydrodesulfurization and denitrification activity than the NiMo/AF-20 and NiMo/AF-10 catalysts. Therefore, the FDU-12 materials after Al modification possessed good prospect of industrial application.

Seawater desalination is to extract clean fresh water from abundant seawater resources, being an important way to solve the shortage of fresh water resources. The traditional seawater desalination technologies strongly have exposed the shortcomings of high cost, high energy consumption and low efficiency in practical applications. Therefore, the development of new technologies and materials for desalination has become the focus of research. Molybdenum disulfide (MoS₂) is a typical layered transition metal sulfide. Because of its chemical stability and excellent light absorption capabilities, it has great application prospects in the field of seawater desalination. As an efficient and environmentally friendly seawater desalination material, MoS₂ has been extensively studied in improving traditional desalination processes and developing emerging desalination technologies. This article focused on the research progress of MoS₂ materials in the application of capacitive deionization, membrane desalination and solar desalination, as well as the challenges of MoS₂ in the industrialization of these three desalination technologies. The future development of MoS₂ materials in the field of desalination was also discussed.

Colloidal crystals are ordered arrays formed by self-assembly of monodisperse colloidal microspheres. The self-assembly of colloidal microspheres is an important way to build the structural color, which is simple, low cost, and no need for complicated and expensive equipment, etc. The structural color produced from colloidal crystals has great potential in the fields of textiles coloring, sensing, anti-counterfeiting, and information encryption, owing to the advantages of high luminance, high saturation, and good light stability, etc. This article introduces the following three aspects in details: the design of the structure and the synthesis of colloidal microspheres, the controllable construction, and the application of colloidal crystals. The advantages and disadvantages of inorganic nanospheres, organic polymer nanospheres, and core-shell nanospheres are reviewed. The assembly methods of colloidal microspheres are summarized, including gravity deposition, heat-assisted assembly, vertical deposition, dip-coating, spraying, inkjet printing, spin coating, magnetic field induced self-assembly, electric field-driven assembly, and interface transfer printing, etc. The application status of the colloidal crystals structure are described and the perspective of future research emphasis on the colloidal structure color system are also presented.

Solid-liquid phase change material (PCM) is essential in the development of thermal energy storage (TES) technology. However,some inherent problems,such as leakage and low thermal conductivity, have seriously weakened the performance of phase change materials. Therefore,choosing an appropriate method to construct form-stable composite phase change material (FSCPCMs) and to effectively improve the thermal conductivity is an important prerequisite for the practical application of phase change materials. Porous carrier encapsulation could provide an effective way to construct shaped composite phase change materials with high energy storage density and excellent heat transfer properties. In this paper,the preparation,structural thermal properties and applications of different FSCPCMs are reviewed,and the effects of pore size and geometry, surface modification, force and composition on the phase transition behavior of FSCPCMs are summarized and discussed in detail. This paper focuses on the design and application of new porous composite phase change materials with high thermal conductivity, high load rate and high latent heat. Finally, based on theoretical, numerical and experimental results, the future research directions of FSCPCMs in phase transition and multi-scale heat transfer in constrained structures and their commercial applications in energy conversion are prospected.

Potassium ion batteries have become a new research hotspot in the field of energy storage devices due to their advantages of high energy density, rich potassium reserves, and low cost. Potassium ions can be intercalated and deintercalated in commercially available graphite anodematerials, which is of great significance for the future industrial development of potassium ion batteries. However, at present, graphite anodes have problems of large volume expansion rate, rapid capacity decay, low rate performance and so on. In recent years, to explore materials suitable for intercalating potassium and methods for inhibiting expansion, more and more electrodematerial systems have been developed. Among them, the biomass carbonmaterial has been widely studied because of its simple preparation, low cost, safety and environmentally friendly feature. This article summarizes the latest research progress of biomass carbonmaterials for potassium ion batteries and analyzes two kinds of potassium storage mechanisms present in carbon-based materials and their respective effects on electrochemical performance. The preparation method and electrochemical performance of some biomass carbonmaterials that exhibit excellent electrochemical performance are briefly summarized. Finally, the further study of the potassium ion battery has been outlined.

With the advantages of high specific capacity, low cost, environmental protection and no need for high-voltage electrolyte, nickel-rich oxide cathode materials have attracted much attention. Although the higher Ni content contributes to improve the specific discharge capacity, it also produces cationic mixing, surface and interface reactions and crack propagation which leads to structural instability, etc., resulting in poor cycle life, low thermal stability and poor storage performance of nickel-rich cathode materials, which hinder their commercial application. In order to give full play to the advantages of nickel-rich LIBs, nickel-rich oxide cathode materials have been carried out varieties of modifications. In the past decade, nickel rich cathode materials have experienced the development stages of ion doping, surface coating, single crystal, core-shell structure, concentration-gradient structure and so on. In this paper, the mechanism and research progress of doping, coating, single crystal and core-shell structure modification were briefly reviewed, and the edges and inherent shortcomings of these methods were analyzed. After that, this paper focused on the analysis of the concentration-gradient materials, which were divided into three parts according to their development stages: nickel-rich core with concentration gradient shell, linear concentration gradient materials and progressive concentration gradient materials. The synthesis methods, modification mechanism and electrochemical performance of them were introduced in detail. In a comprehensive view, the concentration gradient material can fundamentally solve the inherent weaknesses of nickel rich cathode materials, and it was believed that this technology would play an important role in the practical process of nickel rich cathode materials.

Under atmospheric pressure, the graphite/Ti_nO_2n-1 composites were prepared by an carbothermal reduction process of anatase titanium dioxide powders using graphite reductant. The variation of valence state of titanium was investigated by X-ray diffractometer (XRD) in the carbothermal reduction process, and morphology, structure and element composition of the specific reduced sample was analyzed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD results indicated that the graphite/Ti_nO_2n-1 composites with different n value could be obtained with controlling different reduction conditions, and the order of phase transition was TiO₂(anatase), TiO₂(rutile), Ti₉O₁₇, Ti₈O₁₅, Ti₆O₁₁, Ti₅O₉ and Ti₄O₇. The minimum resistivity of the reduced samples was 0.1465Ω·cm, which was prepared at 1250℃ for 20min with the graphite/TiO₂ mass ratio of 5∶10. The adsorption capacity of graphite/Ti_nO_2n-1 composites in methylene blue (MB) bleaching was enhanced in comparison with graphite powers, and the removal efficiency was 1.40～3.20 times of graphite. Under visible light irradiation, the graphite/Ti_nO_2n-1 composites were confirmed to have photocatalytic activity for the degradation of methylene blue (MB) though a little lower than that of anatase TiO₂. The maximum apparent rate constant k of the graphite/Ti_nO_2n-1 composites was 0.0047min^-1.

Green renewable, abundant reserves and low-cost agricultural and forestry wastes have an important position in the field of energy conversion and utilization. In this paper, fungus bran, the most common agricultural and forestry waste in northern China, was used as the raw material, and potassium hydroxide and ammonium borate were used as the activator and dopant, respectively, N, B co-doped fungus bran-derived carbon (NBFC) was prepared by simple high temperature calcination method. NBFC’s micro-morphology and physical structure characterization results showed that NBFC-3 was a honeycomb porous material with a rough surface. The pore size was concentrated at about 2nm and the specific surface area was up to 2968.48m²/g with an interconnected micro mesoporous network structure. The electrochemical performance results indicated that when the current density was 0.5A/g, the specific capacitance of NBFC-3 was as high as 297.2F/g. Even when the current density increased to 10A/g, the specific capacitance could still reach 218.5F/g. After 5000 cycles (current density was 5A/g), the specific capacitance retention rate of NBFC-3 was 94.5%, demonstrating its good rate performance and remarkable electrochemical stability. To sum up, the NBFC was a kind of extremely potential electrochemical energy storage material. The research also provided a new idea for the efficient use of agricultural and forestry wastes.

Cobalt oxide (Co₃O₄) is a typical p-type semiconductor and can be used as a gas sensing material. The gas-sensing properties of Co₃O₄ can be improved by doping non-metallic boron (B) due to the absorbing electron characteristics of boron(B) that makes hole concentration of Co₃O₄ increase. In this paper, B-doped Co₃O₄ microspheres with sea urchin morphology were successfully prepared by low-temperature one-step hydrothermal method using cobalt nitrate hexahydrate [Co(NO₃)₂·6H₂O], boric acid (H₃BO₃) and urea [Co(NH₂)₂] as raw materials. The structures and morphologies of Co₃O₄ before and after boron doping were characterized by various spectra, and the gas sensing properties to ethanol were examined. The results show that boron doping significantly enhances the gas sensing properties of Co₃O₄. When the doped molar ratio is Co∶B=8∶1, the doped Co₃O₄ not only exhibits high response of 26.8 in 1×10⁵μg/L ethanol, which is 4.4 times higher than that of pure Co₃O₄, but also good selectivity and stability at the optimal working temperature of 180℃. So, the B doped Co₃O₄ is a promising gas sensing material for detection of VOCs.

NiMn₂O₄ on reduced graphene oxide (NiMn₂O₄/rGO) was prepared by the hydrothermal method. The effects of graphene on the microstructure, specific surface area, and capacitance performance of CoMn₂O₄/rGO materials were studied. The results show that NiMn₂O₄ nanosheets are deposited on the surface of graphene sheets and the aggregation phenomenon disappeared. Compared with pure NiMn₂O₄, NiMn₂O₄/rGO has a high specific surface area and excellent electrochemical properties. It has a specific capacitance of 1375F/g at 1A/g, while that of pure NiMn₂O₄ is 924F/g. After 5000 charge and discharge, the specific capacitance retention rate of NiMn₂O₄/rGO at 5A/g is 90%, while that of NiMn₂O₄ is 78%. NiMn₂O₄/rGO shows good capacitive properties and has a wide application prospect as an electrode material for supercapacitors.

Previous studies have found that the iron-manganese co-oxide film on the surface of the quartz sand has a high catalytic oxidation capacity for the removal of ammonium and manganese in water. In this study, two pilot-scale filter columns were used to study the removal of bisphenol A (BPA) by the ripening filters, and how the loading change of Mn²⁺ affected the removal of BPA was also investigated. The results showed that 0.48mg/L of BPA was removed with 95.6% of the removal efficiency of BPA and 5.44mg/L of consumed dissolved oxygen (DO). When the Mn²⁺ in influent was about 2.0mg/L, 0.56mg/L of BPA was removed in the 65cm depth of the filter column, and the concentration of BPA did not change obviously in the rest layers of the filter. From scanning electron microscope (SEM), some substance was generated after the oxidation of BPA, which was blocked in the pore structure of the oxide film, causing the compaction of the filter material. At the same time, a small amount of oxide film was found to crack and fall off. Energy dispersive spectrometer (EDS) spectrum indicated that the content increased from 12.14% to 21.10% for C and from 18.50% to 22.58% for O, respectively, but the Mn on the film surface decreases from 63.18% to 42.49%. The reduced manganese substance on the film surface may lead to the decrease in removal of BPA. X-ray Photoelectron Spectroscopy (XPS) energy spectrum showed that the main chemical forms of the oxide film were Mn₃O₄ and MnFe₂O₄, and the presence of [—CH₂—H(OH)]_n covered and blocked the dense porous pores of the film after dosing BPA, which was the main reason for the decrease in the removal efficiency of BPA.

Zn-Al-Ce-LDHs was prepared by hydrothermal method and then used as a new negative material for Zn-Ni secondary battery. The morphology and microstructure of Zn-Al-Ce-LDHs were analyzed by FTIR, XRD and SEM. The electrochemical properties of Zn-Al-Ce-LDHs as the negative electrode materials for Zn-Ni secondary battery were studied by cyclic voltammetry (CV), Tafel polarization curve and constant current charge discharge test. XRD and SEM analysis showed the prepared Zn-Al-Ce-LDHs had nice crystallinity, uniform dispersion and a regular hexagonal sheet structure. The electrochemical tests showed that the Zn-Al-Ce-LDHs had good cycle reversibility and corrosion resistance when it was applied in Zn-Ni secondary battery. The galvanostatic charge and discharge tests also indicated that Zn-Al-Ce-LDHs electrode had excellent cycle stability and charge-discharge characteristics. After 80cycles, the cycle retention rate was 95.1%.

Based on the problem of annulus channeling caused by water invasion of the adjustment during wells cementation, AMPS, AM, AA and SA were used as raw materials to prepare a water-soluble hydrophobically associating polymer AAAS by free radical micelle polymerization to enhance the anti water invasion ability of cementing slurry and improve the channeling resistance of cement slurry in order to improve the cementing quality of such wells. The microstructure was characterized by means of IR, NMR, SEM and GPC. The water invasion resistance and basic engineering performance of AAAS cement slurry system were evaluated. The results showed that AAAS can significantly improve the water invasion resistance of cement paste. Compared with the 0.3MPa water invasion channeling through pressure of blank cement slurry, the water invasion channeling through pressure of 0.9% AAAS cement slurry system was increased to 6.9MPa, which greatly improved the anti channeling ability of cement slurry. The 14d bending strength was 8.2MPa and the compressive strength was 31.5MPa, which can meet the needs of long-term cementing of adjustment wells. Therefore, it was expected that AAAS would have a good application prospect in anti water invasion and channeling prevention of adjustment well cementing engineering.

Due to high viscosity and poor liquidity of heavy oil, the extraction is difficult and costly. The high content of asphaltene is the main reason for the high viscosity of heavy oil. Microorganisms can reduce the average molecular weight of heavy oil by degrading heavy component, thus reducing the viscosity of heavy oil. In this paper, starting from the structure and composition of asphaltenes, the mechanism of biodegradation of asphaltenes is explained , the latest research progress in recent years is summarized,the challenges of the research and application are pointed out,and its development trend is predicted. The biodegradation of asphaltene is mainly through the ring-opening degradation of polycyclic aromatic hydrocarbons, the degradation of long-chain n-alkanes into short chains, and the ring-opening of heterocyclic compounds to remove heteroatoms. However, due to the large molecular weight and uncertain composition of asphaltenes, whether the selected microorganisms can efficiently degrade asphaltenes in crude oil reservoirs still needs to be further explored. The screening of high-efficiency asphaltene-degrading strains and the use of genetic engineering to transform strains should be the focus of future work. In addition, through the combination of strains, the synergistic effect of strains can be used to degrade asphaltene more efficiently.

Volatile fatty acid (VFA) is widely used because of its good biodegradability and high additive value. Currently, production of VFA via anaerobic digestion is a research hotspot. However, the biodegradability of organic matter after hydrolysis was rarely discussed. There is a trade-off between quantity and quality of hydrolysates in anaerobic fermentation process. To further improve the utilization efficiency of organic substances by microorganisms in anaerobic fermentation process and break through the restrictive effect of hydrolysis on anaerobic digestion, anaerobic hydrolysis is divided into rapid hydrolysis and slow hydrolysis according to the different release speed of matrix carbon sources and the different degradation performance of carbon sources in anaerobic fermentation process. It expounds meanings, classifications, advantages, and disadvantages of the two hydrolysis methods respectively, indicating that the release rate and release mode of carbon sources inside and outside cells are the decisive factors affecting the anaerobic acid production and biodegradation performance. Finally, it points out that the combination of rapid hydrolysis and slow hydrolysis is the main research direction of VFA production by anaerobic digestion in the future.

The conversion of lignocellulose into biofuels or chemical products requires pretreatment, enzymatic hydrolysis and fermentation processes. Due to its complex chemical structure, pretreatment is usually performed before enzymolysis to destroy its dense structure and improve the accessibility of the enzyme and cellulose. Deep eutectic solvent (DES) is a new type of “green” solvent, which can effectively remove lignin from lignocellulose, while retaining most of the cellulose. In addition, DES has the characteristics of simple preparation, low cost, adjustable properties, biodegradable and recyclable, which shows great industrial application potential in the production of fuel and chemicals in the lignocellulose biorefinery. In this review, the types and physical and chemical properties of deep eutectic solvent were introduced. The effects of DES pretreatment on biomass components were summarized. Furthermore, the pretreatment effect factors such as the type of substrate and DES, the viscosity of DES, temperature, biological load, microwave and ultrasonic aids, two-stage pretreatment measure and so on were discussed. Then, the compatibility between DES and biology was also analyzed. At last, for the problems and disadvantages of DES, the opportunities and challenges of rational design and recycling of DES were put forward to realize low-cost pretreatment and high -value utilization of lignocellulose.

As a value-added bioproduct, biohexanol synthesis through biological way has attracted extensive attention. Although the cost of biohexanol can decrease using syngas as substrate, the low yield hexanol production limits its application. In this study, the advance of biohexanol production from wasted industrial syngas through biological fermentation is for the first time analyzed on the basis of recent studies. To date, only one strain is reported, which can convert syngas into biohexanol directly, being Clostridium carboxidivorans. This strain prefers to produce acetate, ethanol, butyrate and butanol rather than hexanol. The highest hexanol yield of Clostridium carboxidivorans was 1.06g/L. The performance of biohexanol fermentation can be influenced by several key environmental factors such as the composition of syngas, concentration of inhibitors, mass transfer efficiency of gas-solid, temperature and pH. Optimizing and regulating these parameters are helpful to improve the production of biohexanol. Coculture fermentation is an alternative way for biohexanol production using the bacteria such as C. ljungdahlii, A. bacchi and C. kluyveri, which can be separated into three steps: ①conversion of syngas into acetate and ethanol; ②caproate production from acetate and ethanol via chain elongation; and ③reduction of caproate into hexanol. However, the economic feasibility of coculture fermentation needs to be further proved. The future study will focuses on improving the low yield production of biohexanol which is considered as “bottleneck” issue. It is expected that the hexanol-producing bacteria with high productivity can be obtained through synthetic biology and genetic engineering.

The carboxyl group in graphene oxide (GO) was activated by chemical method, and then GO graft modified triethanolamine oleate (MDLO-GO) was prepared through the reaction of GO and the hydroxyl group at the end of MDLO under certain conditions. Finally, after evenly mixing water, KOH and EDTA, potassium soap, MDLO-GO, emulsifier and defoamer were added in turn to obtain the graphene oxide modified water-based hydraulic support concentrated solution (GO-HDSF). The structure of MDLO-GO was confirmed by infrared spectroscopy and X-ray photoelectron spectroscopy, which proved that GO was successfully grafted to the MDLO molecular chain. The experimental results showed that the viscosity, corrosion resistance and lubricity of GO-HDSF were gradually improved with increasing GO addition. When the mass fraction of GO was 0.004%, the corrosion resistance potential of GO-HDSF increased to 83mV and the current density decreased to 6.5×10^-6A/cm². The maximum without bite load (PB) value of GO-HDSF reached to 481N. The lubricity of GO-HDSF was increased by 11.9% and the corrosion resistance was increased by 97.6% compared with the unmodified concentrated solution. At the same time, the high and low temperature resistance performance was also significantly improved respectively.

Nowadays, the problem of high energy consumption and carbon emission during the organic matter removal in municipal wastewater treatment plant becomes increasingly obvious. Subsequently, the concept of organics recovery, which has both environmental and economic profits, attracted more and more attention. Efficient capture of organic matter from low-intensity municipal wastewater to generate high concentration organics, determines the economic and technical feasibility of organics recovery. Many well-known water treatment processes, such as membrane filtration, high-loaded activated sludge process, flocculation, have been re-recognized and applied to organics capture due to their high organic matter retention characteristics. In this paper, according to the concentration process of organic matter in these technologies, they were divided into two categories: “directional aggregation” and “passive accumulation”. Based on understanding their capture mechanism, this paper further discussed the approaches to improve their capture efficiency and short slabs that need to overcome for large-scale application. Then, this paper summarized the recovery methods of the concentrated organics, and pointed out that the key of maximum recovery is to select the appropriate pretreatment according to the characteristics of concentrated organics. Finally, based on the technology maturity, energy consumption and operation cost of organics capture process, the feasibility of wastewater treatment system aiming at resource recovery was prospected.

The complex pollution of iron, manganese, and ammonia nitrogen in drinking water sources has become more and more common in recent years. The phenomenon of excessive ammonia nitrogen associated with iron and manganese in the surface water is seasonal, and mostly occurs in reservoir water, posing a threat to people’s daily drinking water safety. In this paper, the causes and hazards of compound pollution were analyzed, the traditional treatment methods and their limitations were briefly introduced. The origin of the iron-manganese active oxide film contacted catalytic oxidation method, the action mechanism of the oxide film, the preparation process of the mature filter material, the removal characteristics of pollutants and the recovery of catalytic activity was described. Two reaction mechanisms, the oxygen free radical theory of activating molecular oxygen and the oxidation theory of active manganese on the oxide surface, were analyzed. Finally, it pointed out that the research on the formation and action mechanism of the contact catalytic oxidation method still needs to be further studied. The further exploration was prospected and the idea of accelerating the start-up of coordination catalysis was proposed. It is believed that the method has great development potential and broad application prospects in the future.

Circulating fluidized bed (CFB) incinerator is a new type of incineration technology. The benefits of circulating fluidized bed incinerator include wide application, stable combustion and low emission. High temperature corrosion of the superheater can be avoided and bed temperature can be adjusted flexibly if the boiler steam pressure, temperature parameters and capacity are increased by the arrangement of the external heat exchanger (EHE). Although related researches on external heat exchangers have been done at home and abroad at present, they are mainly focused on coal-fired boilers in power plants. The EHE is seldom used in municipal solid waste (MSW) because of the low boiler steam pressure and temperature parameters. In this paper,research status of CFB incinerator with external heat exchanger were reviewed. The current situation and technical problem of CFB coal-fired boiler with external bed at home and abroad which has same heat exchange principle and great reference value were also introduced. The influencing factors related to the heat transfer coefficient and fluidization characteristics inside EHE were analyzed, problems in experiment and EHE, such as large temperature deviation at the outlet of heating surface and poor fluidization quality in the side wall area were pointed out, the improvement measures were put forward, and the future research idea of external heat exchanger for MSW CFB incinerator was proposed. In the end, the current research emphases were summarized, and the improvement measures for the experiment and EHE test were put forward, which provides reasonable suggestions for the future manufacturing of the high-parameter waste incinerator.

As an eco-friendly catalytic material, carbon-based catalyst can effectively prevent undesirable leaching and secondary pollution of toxic metal ions. Three reaction mechanisms of carbon-based catalysts for activating persulfate (PDS) to degrade organic pollutants are elaborated and the advantages and disadvantages of the radical and nonradical mechanisms are compared and discussed in this review. The research process of using of different carbon materials, such as activated carbon, graphene, carbon nanotubes, mesoporous carbon, nano-diamonds, and biochar as the catalyst to activate persulfate to degrade organic pollutants are summarized. The selectivity and efficiency of different carbon-based materials for degradation of organic pollutants are compared and the problems of various carbon-based materials have also been briefly summarized. Then, the effects of doping modification on the catalytic activity are evaluated. For the weakness of poor stability and low reusability of carbon-catalyst, some regeneration methods are summarized in this paper. Finally,the prospects of carbon catalysts used to activate PDS to degrade organic contaminants in real wastewater are given.

The production of apricot shell activated carbon is an important part of apricot industry in Hebei Province. Its production scale is constantly expanding, and its technology is constantly improved. However, the traditional production technology of apricot shell activated carbon still has problems such as single product, insufficient utilization of apricot shell resources, low added value of product, high energy consumption, high pollution and low efficiency in the processing process. Applying biomass gasification technology to the production of activated carbon, and based on the multi generation technology of material gasification of Nanjing Forestry University, a 3MW project of apricot shell gasification power generation co-production of activated carbon, heat and fertilizer has been completed. This paper introduces the technical characteristics and operation of the 3MW apricot shell gasification power generation co-production system of activated carbon, heat and fertilizer and analyzes the balance of the system and the economic indicators such as investment cost, investment recovery period and operation cost. The results show that the project can use 39000tons of apricot shell every year, save raw coal converted into 7500tons of standard coal, reduce 37380tons of CO₂, and achieve good environmental benefits. The investment recovery period is more than one year, and the economic benefits are very significant. The project is technically mature and advanced, fully in line with the development direction of green industry, recycling industry and sustainable industry. It meets the development concept of “energy saving and environmental protection industry”, and is suitable for large-scale promotion and application.

When the low-C/N ratio domestic sewage is treated by the multi-stage A/O-MBR combination process, there is a problem that the TP removal rate is low. The removal of the phosphorus is enhanced by the improved multi-stage A/O-MBR combination process of increasing internal reflux. The removal effect of modified multi-stage A/O-MBR combination process on TP in low C/N ratio domestic sewage was studied. The mechanism of removal of modified multi-stage A/O-MBR combined process sludge denitrifying phosphorus was investigated by static analysis of sludge. The results showed that the improved multi-stage A/O-MBR combination process had good TP removal efficiency with the average removal rate of 86.36%. At the same time, the effects of COD, TN and nitrogen removal were good, and all reached the first-class A emission standard. The proportion of polyphosphate bacteria and denitrifying phosphorus accumulating bacteria were increased by the improved multi-stage A/O-MBR combination process, and the removal effect of TP by the combined process was strengthened.

Te, Au, Pt and Pd in the copper-rich solution from copper anode slime by sulfation roasting-sulfuric acid leaching treatment were reduced by Fe²⁺, and new ecological Te colloid were simultaneously formed to selectively capture the precious metals of Au, Pt and Pd. The dissolution mechanism of precious metals in copper-rich solution were analyzed based on pretreatment of copper anode slime. The φ-pH diagram of As-Fe-H₂O system were drawn by thermodynamic calculation to instruct the control of electrode potential of the copper-rich solution. The mechanism of in-situ reduction of rare and precious metals were discussed based on electrode potential of main metal ions in copper-rich solution. Under the optimal conditions of reaction temperature of 85℃, reaction time of 1.5h, stirring speed of 300r/min, and Fe²⁺ dosage of 2g/L, the precipitate efficiency of Au, Ag, Pt, Pd, Se, Te and As were 100%, 100%, 99.2%, 99.6%, 33.3%, 36.1% and 16.8%, respectively. The grades of Te, Au, Ag, Pt and Pd in the precipitated residue are 18.24%, 124g/t, 10.54%, 1010g/t and 320g/t, respectively. XRD analysis shows that the main phase of the residue is AgCl, and other components did not show obvious diffraction peaks due to amorphous or low content. The microscopic morphology of the residue is mainly fine powder and particles. SEM images of the residue shows that Ag and Cl have obviously consistent enrichment areas, As and Fe have similar enrichment areas to form AgCl and FeAsO₄ in the residue. The proposed process environmentally friendly and low cost with simplicity in operation, which had achieved efficient and comprehensive recovery of rare and precious metals in copper-rich solution.

In this paper, a deep neural network consisting of a LSTM layer, two rectified linear unit layers, and two fully connected layers was established. Data pre-processing such as moving average and minimum analysis period for input parameters to reduce noise was used. During the network training, the dropout technique to prevent overfitting was used. Simulation results and comparison with the existing technology showed that the model has good prediction ability for slurry pH, outlet SO₂ concentration and desulfurization rate. The actual working condition data of a 2 × 350MW thermal power plant and this deep neural network model to test the effect of limestone slurry supply density on the system’s desulfurization performance was also combined.