Graphene, as a new type of nano materials, has good adsorption and removal performance for various pollutants in water. However, the final state of graphene nanopowder makes it difficult to separate from the solution after use, resulting in secondary pollution. Therefore, the construction of large volume three-dimensional graphene structure can effectively remedy the problem of difficult separation of nano materials in water treatment. This paper introduced the three-dimensional structure preparation methods commonly used nowadays, such as template method, self-assembly method and so on, but these methods were usually cumbersome steps, many influencing factors and required conditions and other shortcomings, which were easy to produce structural defects in the process, and thus affecting the mechanical properties of the three-dimensional structure. The 3D printing method had the advantages of simple operation, accurate structure design and batch preparation through computer data control. It can prepare excellent three-dimensional structure and modify or increase its mechanical properties through flexible control of slurry components. To sum up, the key to make 3D printing graphene suitable for water treatment was to configure the slurry that met the viscosity requirements of 3D printing and to make the 3D structure havng certain required mechanical.

Utilizing huge energy release during cavitation bubble collapse (i.e., sonochemical effect), hydrodynamic cavitation (HC) is an effective, green chemical process intensification technology, which has become a research hotspot around the world. HC technology, with the advantages of low equipment cost, good scalability, and effective synergism with other physical or chemical means, has a huge potential for industrial applications. The present review introduces HC phenomenon and its characteristics. The research and application progresses and corresponding mechanisms of HC technology in three representative applications, i.e., organic wastewater treatment, water disinfection, and biofuel production, were summarized, indicating its potential in industrial applications. Moreover, the development process and the state of the art of hydrodynamic cavitation reactors, which are utilized to induce HC phenomenon, were discussed. Finally, based on the development trend and the authors' research experience, the existing issues and research direction of HC technology were proposed. The present review can provide constructive suggestions for accelerating the development and industrial application of HC technology.

Based on the model of the nucleation reduction of single silicon particles, a mathematical coupling model of reaction, radiation and convection heat transfer of silicon particles in the conveying bed was established. With the help of CFD software FLUENT, the process of energy and mass transfer in the conveying bed was numerically simulated, and the effects of wall temperature, nitrogen flow rate, preheating temperature and particle size of silicon powder, powder gas ratio and diluent ratio on the temperature field and conversion rate of silicon powder in the conveying bed were analyzed. In this paper, a method was proposed to transform the reaction process of single particle into the whole reaction process of particle group in the numerical calculation domain, and the particle size and unreacted silicon particle size can be continuously monitored, which provided a new idea for numerical simulation of granular flow reaction. The reaction process of silicon powder in the conveying bed was similar to that of pulverized coal combustion, and a high temperature zone would be formed in the conveying bed to accelerate the nitriding process of silicon powder. The higher the reaction temperature and the smaller the particle size, the more intense the reaction process and the shorter the time required for the silicon powder to reach complete nitriding. The model showed that in order to make the silicon powder with the particle size of 2.5μm react completely and the maximum temperature did not exceed the decomposition temperature of Si₃N₄ at 2173K, the wall temperature of conveying bed should be controlled at 1773K in the nitridation time of above 170s at the preheating temperature of 1273K with the ratio of powder to gas of 0.2 and the diluent ratio between 0.5 and 1.

Efficient thermal management technology is imperative for the normal operation of high-powered electronic devices. In this paper, a novel aluminum foam and pin fin hybrid heat sink (AFPFH heat sink) was proposed to further enhance the cooling performance. A combined experimental and numerical study was conducted to investigate fluid flow and heat transfer characteristics of AFPFH heat sink subjected to forced water flow. The streamline distributions, temperature distributions, friction factors, heat transfer performances, and conjugate heat transfer characteristics between pin fin and metal foam were presented. Results showed that the bottom wall temperature of AFPFH heat sink was significantly reduced in comparison to the traditional pin fin heat sink, and the average Nusselt number was improved by 33.9%—41.5%. However, the deduced flow resistance was increased by approximately 7.9—10.5 times. The heat transfer augmentation mechanism of AFPFH heat sink was that the addition of high thermal conductivity aluminum foam into pin fin heat sink enhanced overall effective thermal conductivity, which improved conductive heat transfer through the metal foam ligaments. Meantime, the superior convective heat transfer capability at the porous interfaces promoted heat dissipation by the cooling fluid. The present results could provide a theoretical guideline for the development of efficient cooling alternatives for electronic devices.

The effect of aeration on the process of membrane separation at a low superficial liquid velocity was researched in an air sparging tubular membrane system for filtering a Kaolin suspension. The influences of aeration on the hydraulic characteristics in membrane module and the membrane fouling process were discussed, and the impacts of aeration on the filter medium and the composition of membrane filtration resistance were also studied. The results showed that a gas-liquid two-phase flow was formed on the membrane surface by injecting air, and the membrane flux could be stably maintained above 15L/(m²·h) at a low membrane superficial liquid velocity. Moreover, the Reynolds number increased from 1800—2500 to 3300—4500, indicating that the turbulence on the membrane surface was significantly enhanced by aeration. Besides, the membrane fouling number was controlled at a low level under a low membrane superficial liquid velocity, which saved operating energy consumption. In addition, the membrane cake layer could be reduced by air injecting, leading to a reduction in the total membrane resistance, but which had little effect on the retention rates of Kaolin suspension. However, the Kaolin particle size became smaller as a result of the strong gas-liquid mass transfer, and the membrane surface formed a filtration resistance dominated by an irreversible pollution layer, which was not conducive to the long-term control of membrane fouling.

For desalination by membrane distillation, direct current was applied to self-made conductive carbon membrane to produce Joule effect which can enhance the air gap membrane distillation process. Experimental results showed that the prepared coal-based carbon membrane has good structural stability within 100℃. In the experimental range, the rejection rate of carbon membrane for sodium chloride was over 99.96%, and the introduction of Joule effect during membrane distillation process would not produce additional membrane fouling. The Joule effect could increase the permeate flux up to 60%, and it gave better enhancement on the membrane distillation and higher electric conversion efficiency at low temperature. The introduced Joule heat can not only evaporate water but also increase the temperature of material and liquid, improving temperature polarization and increasing the driving force of mass transfer. The Joule effect also affects the mass transfer coefficient in the process of membrane distillation. When the feed temperature was 50—80℃, affected by Knudsen diffusion and molecular diffusion, the mass transfer coefficient would reduce at 1A current, and increase at 3A and 5A current. Meanwhile, the introduction of current into the carbon membrane will not damage the structure of the carbon membrane and the PDMS layer on its surface, and there is no synergistic effect such as REDOX in the carbon membrane. The research content of this paper enriches the methods of membrane distillation seawater desalination process and also provides a basis for simulation research and industrial application of the Joule effect affecting the membrane distillation process.

In view of the high temperature corrosion phenomenon in the hot corner area of a dual tangential boiler, in this paper, a method of adjusting the secondary air flow in the same layer to improve the reducing atmosphere in the upstream of the hot corner was adopted. Based on Fluent software, the combustion conditions in the furnace under different cold angle secondary air flow conditions were simulated and compared with the original conditions. The high temperature corrosion severity of water wall was reflected by the distribution of CO concentration near the wall. The results showed that the area with high CO concentration (>8%) near the water wall of dual tangential circular boiler could be basically eliminated by increasing the secondary air volume at the cold angle, and the problem of high temperature corrosion of the water wall could be greatly alleviated. Under 5% and 10% working conditions, the proportion of safe area near the furnace wall increased by 1.20% and 1.35%, respectively, while the proportion of seriously corroded area decreased by 0.013% and 1.02%, respectively. The screen bottom temperature, pulverized coal burnout rate, average furnace outlet temperature and oxygen volume fraction almost remained unchanged, and the average NO _x mass concentration at the outlet increased by 2.99% and 8.89%, respectively. 15% working condition had the best anti-corrosion effect, and the proportion of safe area near the wall increased by 3.60%. Meanwhile, the proportion of serious corrosion area decreased by 4.99%, and the temperature at the bottom of the screen and the burnout rate of pulverized coal increased slightly. The average temperature and oxygen volume fraction at the furnace outlet almost hardly changed. The average mass concentration of NO _x at the outlet increased by 18.91%. In the actual adjustment process of general power plants, the increment of cold angle secondary air should be set between 5% and 10%. For power plants burning high sulfur coal with low NO_x emission, the increment of cold angle secondary air can be set at about 15% to minimize high temperature corrosion.

As a new energy source, biodiesel has attracted widespread attention. Microwave heating is widely used to produce biodiesel due to its high efficiency. However, the non-uniform heating of microwave is the main problem that needs to be solved urgently. So, a mode stirrer was introduced into a microwave reactor with an interlayer, and the multi-physics field simulation of microwave heating process was carried out by coupling the Maxwell and heat transfer equations with COMSOL software. The arbitrary Lagrangian-Eulerian method was used to deal with the mode stirring, and the influence of different mode stirrer parameters on the microwave heating characteristics was discussed. The results showed that compared with the microwave heating model without mode stirring, the electric field distribution in the material was changed at all times by mode stirring, thus improving the heating efficiency and heating uniformity. With the increase of the height and length of the mode stirrer, the material average temperature and coefficient of variation (COV) showed a downward trend on the whole. The average temperature of material increased linearly with the increase of stirring speed, and COV showed an overall upward trend with the increase of stirring speed. Through response surface analysis, it was found that the primary and secondary order that affected the average temperature and COV was: stirrer height > stirrer speed > stirrer length, where the interaction between the stirrer height and the speed had a significant effect on the average temperature. Considering the average temperature and COV, the best stirring conditions obtained by response surface optimization were stirrer height λ_H of 0.164, stirrer length λ_B of 0.31, stirring speed N of 30r/min, COV of 0.11×10^-2, and average temperature of 22.15℃.

The effects of surface structure and wettability on the heat transfer performance of pool boiling between liquid and solid wall were investigated from the nano scale by molecular dynamics method. The solid wall consists of smooth surface, concave and convex hemispherical nanostructure surface.The wettability between liquid and solid wall ranged from super hydrophilic to super hydrophobic. The changes of liquid layer morphology, temperature and heat flux of liquid argon on the three solid wall surfaces during heating were illustrated. The results showed that the boiling process of liquid argon layer could be roughly divided into two heating stages. One stage was that the liquid argon layer was adsorbed on the solid surface, and the other stage was that the liquid argon layer was separated from the wall. In the first stage, the increase of argon layer temperature, heat flux and the generation rate of gaseous argon atoms were greater than those in the second stage. There were obvious inflection points in the changes of argon layer temperature, heat flux and the amount of gas argon on the hydrophilic surface, while there was little difference in the two-stage heating process of the hydrophobic surface. The concave and convex hemispherical nanostructures on the hydrophilic surface promoted the generation of bubbles and the changes of temperature and heat flux. However, the concave and convex hemispherical nanostructures on the hydrophobic and superhydrophobic surface had different influences on generation of bubbles and temperature and heat flux. The calculation results provided a theoretical basis for pool boiling heat transfer and microstructure selection.

Heavy organic matter, such as coal, heavy oil and biomass, is abundant in hydrocarbon covalent structures. Its light-hydrocarbon and chemicals-oriented conversions are the main goal of processing and utilization. Pyrolysis is the most direct and fundamental reaction process in processing of heavy organic matters. As an important product during pyrolysis, the distribution and evolution characteristic of volatiles are the key and hot research issues. In this paper, the formation process of volatiles during pyrolysis of heavy organic matter was reviewed, and the staged changes in terms of reaction types and volatile composition with the increase of temperature were summarized. Taking coal, oil sand, oil shale, biomass, oily sludge, municipal sludge and waste rubber as examples, the similarities and differences in pyrolysis volatile generation between different source of heavy organic matters were compared. As to methods for the analysis of volatile matter emission characteristics during pyrolysis, the mass spectrometry and Fourier transform infrared spectroscopy were mainly introduced. Simultaneously, the application of these methods in the study on the organic structure of heavy organic matter, the optimization of pyrolysis operating conditions, the control of pollutant generation and the design of pyrolysis catalyst were illustrated. Moreover, the methods and examples of quantitative evolution gas analysis for pyrolysis process were listed. In the hope of providing references for the pyrolysis research of heavy organic matter, some suggestions were putting forward, especially for the technology development prospects of evolution gas analysis during pyrolysis of heavy organic matter.

Ammonia is not only a low-cost chemical material, but also has some advantages such as high energy density, convenient for transportation, and combustion without CO₂ emissions. Therefore, ammonia fuel is a novel clean energy with broad application prospects. Ammonia fuel has the potential to replace fossil fuels such as gasoline and diesel. Therefore, it can be anticipated that ammonia fuel would be a new way to solve environmental pollution and fossil energy shortages. This paper summarized physical and chemical properties and combustion characteristics of ammonia fuel, and compatibility of ammonia fuel and some materials was introduced as well. What’s more, the application research progress of ammonia-gasoline fuel, ammonia-diesel fuel and ammonia-heptane fuel was also summarized respectively. Furthermore, the opportunities and challenges of ammonia as a potential fuel were discussed. In particular, the problems of ammonia were pointed out, such as high energy consumption, toxicity and corrosivity, and combustion defects. Accordingly, the corresponding solutions were analyzed emphatically. Under the background of peak carbon dioxide emission and carbon neutrality, ammonia fuel had a late developing advantage in China.

The boiler-turbine coupling power system based on hot air recirculation (HAR) process can improve the efficiency of a thermal power plant significantly, and has the advantages of low investment and high operation safety. In order to solve the problem of safe and efficient operation of the HAR system in the whole load variation range, an in-service 600MW hard-coal-fired power unit was taken as the reference unit, and the variable load simulation of the HAR system was carried out by using the Ebsilon software. The results showed that, the exhaust gas temperature of the waste heat recovery system decreases with the decrease of power load, which might lead to serious low temperature corrosion risk for air preheater under low load. For the existing HAR system, under low load it is difficult to remain a safe cold-end metal temperature for the rotary air-preheater against low-temperature acid corrosion by adjusting the heat absorption of the high-pressure and low-pressure economizers. In order to ensure the safe and reliable operation of the heating surfaces of the HAR system in the whole load variation range, an optimized HAR system was proposed by adding a heat-bypass pipe into the waste heat recovery system. In the load range of 50%—100%THA (turbine heat acceptance), the application of the optimized HAR system could reduce the standard coal consumption of the reference unit by 1.94—3.32g/(kW·h), thereby achieving marked energy-savings in the whole load variation range. To promote the novel technology into practice, a method of controlling the operation of the optimized HAR system was proposed.

Aiming at the problems of high Na content in the coal of the Xinjiang Naomaohu coal mine, which may cause corrosion and contamination of the inner wall of the gasifier, gasifier slagging and contamination and poor slag discharge during the gasification process, the migration behavior of sodium in Naomaohu coal during CO₂ gasification process was studied by laboratory gasification test and Factsage thermodynamic simulation test. The gasification reaction characteristics of Naomaohu coal were studied by thermogravimetric experiment. Using SEM-EDS, XRD, ICP-OES and other methods, the residue of Naomaohu coal at 800—1100℃ under the CO₂ gasification conditions was analyzed and characterized. Combined with the calculation method of chemical thermodynamic equilibrium, the distribution of Na in Naomaohu coal in the gas phase during CO₂ gasification was studied, and the precipitation characteristics of Na during the gasification process were analyzed. The results showed, as the temperature increased within a certain reaction time, the precipitation amount of Na in Naomaohu coal gradually increased at 900—1000℃. The sodium element in the flue gas mainly existed in the form of NaCl(g), NaOH(g) and Na(g). This part of Na was not concentrated in the residue, but was discharged with the flue gas. The main component in the residue at 800℃ was CaCO₃. When the gasification temperature was higher than 900℃, the residue began to melt, and the amount of the eutectic in the residue increased with the increase of temperature. Na in Naomaohu coal existed in the form of aluminosilicate at 800—1100℃.

It is a challenge for the exploitation of offshore gas hydrate reservoirs that the caprock is not closed and the cementation is weak. Direct depressurization always obtains high water yield and low gas to water ratios, which may also induce reservoir instability. Therefore, a reservoir reformation method based on hydrate principle was proposed, that is, CO₂ was injected above the hydrate reservoir to form an artificial CO₂ hydrate cap, so as to construct a relatively closed mining environment. Based on the previous works, this paper investigated the feasibility of injecting CO₂ + N₂ mixture to reform and exploit CH₄ hydrate reservoir. Results show that a CO₂ hydrate caprock with low permeability and good stability can form from the injected gas, which effectively reduces the water production and improves the recovery ratio of CH₄ during depressurization. When the proportion of N₂ in the injected is high, the presence of excess N₂ can promote the decomposition of CH₄ hydrate. However, N₂ always is produced with CH₄, increasing the difficulty of subsequent gas separation. When the proportion of CO₂ in the injected gas is high, the water blocking effect of the formed artificial caprock is enhanced, but CO₂ production also increases, and the further improvement of CH₄ recovery is limited. The follow-up research needs to further optimize the injection-production process conditions to improve the production efficiency and reduce the energy consumption of gas separation.

Hydrogen energy has the advantages of high energy density, environmental protection, cleanness, and renewable energy. It has become an important direction for future energy development and is regarded as the only way to achieve carbon emission reduction. However, the core problem of the development of hydrogen energy is that the cost of using hydrogen is too high, which has no economic advantage compared with electric vehicles and traditional fuel vehicles. From the perspective of the hydrogen production-transport-hydrogenation industrial chain, it is found that the cost of hydrogen production from electrolysis of water is much higher than that of fossil energy production. At the same time, the cost of hydrogen is mainly raised in the hydrogen transportation and hydrogenation links. This is mainly due to hydrogen storage is not easy. Under the existing long tube trailer transportation conditions, the amount of hydrogen transported each time is too small and the efficiency is not high. At the same time, because the number of fuel cell vehicles is too small, the daily filling volume is insufficient, and the key equipment of the superimposed hydrogen refueling station localization, fixed capital investment is too high, resulting in too high depreciation costs, increasing the cost of hydrogen. In response to this problem, specific suggestions for reducing costs were given, including increasing the pressure of hydrogen transportation to increase the amount of hydrogen carried per time; speeding up scientific and technological research and nationalizing key equipment; breaking through policy restrictions to achieve hydrogen production in the station; optimizing the hydrogen refueling station process, reduce daily operating costs, etc.

The distribution characteristics of magnetic ash particles in different size fractions of gasification slag were studied by sieving and magnetic separation with entrained flow gasification coarse slag and fine ash as raw materials. Results showed that with the decrease of ash particle size, the content of magnetic ash particles in coarse slag and fine ash increased first and then decreased, and the content of magnetic ash particles in coarse slag was higher than that in fine ash. In the coarse slag, the distribution of magnetic ash particles was the most in the 0.5—0.25mm size fraction, and the proportion of the fraction in Shenning gasifier and GSP gasifier coarse slag was also the highest, which were 38.42% and 37.16%, respectively. Besides, the yield of magnetic ash particles in each size fraction increases with the decrease of particle size. In the fine ash, the distribution of magnetic ash particles was the most in the 0.074—0.045mm particle size fraction, while the proportion of fine ash particle size composition was the highest in the > 0.25mm particle size fraction, and the yield of magnetic ash particles was not high in each particle size fraction, showing a law of increasing with the decrease of particle size. During the gasification process, magnetite would be more concentrated in the large-size coarse slag that was agglomerated and highly vitrified, but there was still a considerable amount of iron-containing phase which was not magnetic. The distribution characteristics of magnetic ash particles in different size fractions of coal gasification slag could provide basic data support and application ideas for the classification and high value utilization of coal gasification slag.

A kind of mesophase pitch-based microspheres (MPMB-et) with perfect spherical shape and narrow particle size distribution were prepared by emulsion-polymerization method from petroleum-based isotropic pitch. After pre-oxidation and carbonization, the mesocarbon microbeads (MCMB-et) were obtained. The properties of MCMB-et were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and other analytical methods. Subsequently, the electrochemical performance of microspheres as the anode material for lithium-ion battery was tested. Results showed that MCMB-et had a large specific surface area (13.35m²/g), wide interlayer spacing (0.352nm) and moderate structural disorder degree (the orientation of carbon layers with the MCMB-et were distorted and irregular), which promoted the intercalation and extraction rate of lithium ions between the graphite-like flakes and active sites. Compared with the MCMBs prepared by the direct thermal polycondensation method (MCMB-t) and the direct emulsification method (MCMB-e), the MCMB-et prepared by the polymerization-emulsification method had obvious advantages in terms of cycle performance and rate performance. MCMB-et could still deliver a reversible capacity of 325.3mAh/g at a current density of 500mA/g for 100 cycles and maintain a specific capacity of 240.0mAh/g at a high current density of 2A/g.

With the implementation of green chemical industry strategy, titanium silicalite has attracted widespread attentions due to its unique selective epoxidation ability. Therefore, the rational structure regulation of titanium silicalite is the key to enhance the olefin epoxidation. This paper systematically summarized the synthesis strategies of high-performance titanium silicalite by adjusting the structure type, the molar ratio between Si and Ti atoms, the surface hydrophobicity and the mass transfer in particles, and the industrial process of TS-1 was introduced. Moreover, using the metal-loaded titanium silicalite as the example, we highlighted the reaction performance and mechanism of propene epoxidation with H₂ and O₂, and affirmed the importance of the titanium and the metal dual sites in the catalyst. Among them, the efficiency of metal sites could be tuned from three aspects of electrical property, size effect and space distribution, as illustrated based on the Au-based catalysts. Moreover, based on the current problems and challenges of propene epoxidation with H₂ and O₂, potential solutions and future directions were further proposed.

In recent years, researchers have found that composite molecular sieves have many advantages, such as rich pore structure, good hydrothermal stability and adjustable surface properties, which show higher reactivity and better isomer selectivity than single molecular sieves in hydrocarbon isomerization. The microporous-microporous composite molecular sieves composed of MOR, Y, β, ZSM series molecular sieve, SAPO series molecular sieve and the microporous-mesoporous composite molecular sieves composed of microporous molecular sieve and MCM-41 or SBA-15 mesoporous molecular sieve were reviewed in this paper. The research and development directions of composite molecular sieves for hydroisomerization were prospected, and it is pointed out that the composite molecular sieves for real petroleum fractions isomerization still need more in-depth and systematic researches. Green and efficient synthesis of composite molecular sieves and their activity and selectivity improvement in hydroisomerization through structural design and acid regulation are the focus of future research.

The utilization of high-efficiency non-noble metal-based electrocatalysts is crucial to improve the overall efficiency of electrocatalytic reactions such as hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and oxygen reduction reaction(ORR). Recently, the surficial/interfacial modulating to induce novel physicochemical properties of electrocatalysts and improve their catalytic activity has attracted much attention, as it plays an important role in guiding exploitation and application of energy conversion technology. This paper reviews the recent advances in the surficial/interfacial modulation strategies for designing non-noble metal-based electrocatalysts and meanwhile reveals the key features of the optimization and improvement in the activity of the electrocatalysts from these modifications. This paper also proposes perspectives from the aspects of catalyst preparation, advanced characterization methods, theoretical calculations, and application evaluations on the challenges and research directions of non-noble metal-based electrocatalysts for the future, which could provide reference for the large-scale application of clean energy.

Lignin is a kind of biomass resource with complex structure and abundant yield, but it has low utilization rate. It can be depolymerized into high value-added products through catalytic pyrolysis and has broad application prospects. This paper introduces the research methods of catalyst mechanism and the mode of action of catalysts, and compares the catalytic performance, product yield, product distribution, catalytic mechanism and advantages of molecular sieve catalysts, metal oxide catalysts and metal salt catalysts commonly used in catalyzing the pyrolysis of lignin. Molecular sieve catalysts have strong deoxygenation ability and high acidity, but low liquid product yield; metal oxide catalysts have the advantages of high liquid product yield and strong thermal stability, but they rely on the adjustment of catalyst acidity and alkalinity; although metal salt catalysts are highly efficient and inexpensive, they have poor thermal stability and are easy to inactivate. At the same time, this article puts forward a prospect of lignin catalytic pyrolysis. The research on pyrolysis catalysts in the future needs to be in-depth and systematized. According to the types of lignin and target products, the design of composite catalysts, core-shell catalysts and multi-catalyst cooperative catalysis is the development trend of pyrolysis catalyst.

Lignin is an ideal precursor of carbon materials because of its three-dimensional network aromatic ring structure, abundant source, high carbon content, rich and controllable functional groups. Lignin-based carbon materials with special functions could be fabricated through chemical modification and microstructure regulation, which were widely used in the fields of energy catalytic conversion, electrochemical energy storage and environmental remediation. In this review, the latest research progress of lignin-based carbon material catalysts was presented, and the preparation methods of lignin-based carbon material catalysts were summarized. What's more, it focused on the fundamental research progress of lignin-based carbon material catalysts in the thermal catalytic reaction such as oxidation reaction, hydrogenolysis reaction, esterification reaction, hydrolysis reaction, dehydration reaction and Fischer- Tropsch synthesis, electrocatalysis such as hydrogen evolution reaction in water splitting and oxygen reduction reaction in Zn-air battery, as well as photocatalysis of organic pollutants degradation. However, it was still a challenging task to build the lignin-based carbon material catalyst with high activity, high stability, low cost and large-scale production. In the future research, it was necessary to strengthen the research on the basic chemical structure and microstructure regulation of lignin, the interaction between active components and lignin carbon material support, and the enhancing mechanism of lignin-based carbon material catalyst in the catalytic reaction, so as to make use of its advantages of low cost, three-dimensional structure and adjustable microstructure characteristics, and to expand the fields of high-value utilization of lignin biomass resources.

Carbonylation of dimethyl ether over mordenite has gained great attentions due to its mild reaction conditions and high product selectivity. The unique structure of mordenite endows it high catalytic efficiency, but mordenite also has the problems of carbon deactivation, short lifetime and poor stability. This paper summarizes the progress of mordenite modification in recent years towards overcoming the above problems. The modification methods are divided into four categories, namely acid sites regulation, mesopore introduction, morphology and grain size control and metal modification. These four methods can improve the activity and stability of mordenite catalyst by regulating the number of active sites, enhancing the mass transfer efficiency, or inhibiting coke deposition, respectively. Based on the existing results, the future modification of mordenite should be focused on removing the coking sites in the channels by methods for high-efficient mass transfer.

In order to meet the olefins requirement of the national Ⅵ standard, a series of FCC light gasoline aromatization catalysts were prepared by changing the alumina species. Besides, the acidity and texture properties of the catalysts were investigated. The physico-chemical properties of the catalysts were characterized by XRD, N₂ adsorption desorption, SEM, IR and Py-IR. The aromatization properties of the catalysts were evaluated using FCC light gasoline as feedstocks. The results showed that the introduction of different types of alumina had no effect on the structure of ZSM-5 molecular sieve. However, the acidity of ZSM-5 zeolite could be significantly changed and the Lewis acid sites increased significantly. Besides, alumina materials with uniform and relatively small surface and pore volume were more favorable to the aromatization reaction of light gasoline. The olefins volume fraction of light gasoline decreased 18.18% significantly, volume fraction of isoparaffins increased 10.51% and aromatics increased 2.75%, and octane loss was small (-5.1) and controllable.

Nickel phosphide (Ni _x P _y ) has many crystalline phases, such as Ni₃P, Ni₁₂P₅, Ni₂P, Ni₅P₄, etc. It is important to study the preparation rule and stable existence conditions of each crystalline phase for the development of catalysts based on Ni _x P _y . In this paper, the effects of phosphating time, phosphating temperature, Ni/P molar ratio, phosphating gas velocity and phosphorus source on the crystal phase were investigated. The results showed that three crystalline phases of Ni₅P₄, Ni₂P and Ni₁₂P₅ can be obtained with Ni₃P and red phosphorus as precursors. Only Ni₂P and Ni₁₂P₅ crystal phases can be obtained with hypophosphite as phosphorus source. The reaction temperature was the main factor affecting the crystal phase when red phosphorus was used as the phosphorus source. Ni₅P₄, Ni₂P and Ni₁₂P₅ crystal phases were obtained at 500℃, 600℃ and 800℃, respectively. Ni₃P, Ni₂P, Ni₁₂P₅ and Ni₅P₄ were used as cocatalysts to prepare photocatalytic composites. All the four cocatalysts of Ni _x P _y can significantly enhance the hydrogen production activity of CdS. Ni₅P₄/CdS indicated the best hydrogen production capacity, which was 5.4 times that of CdS. The results of characterization showed that the introduction of Ni _x P _y could effectively inhibit the carrier recombination and enhance the photocatalytic activity of CdS.

Integrating microbial electrolysis cell (MEC) into anaerobic digestion for enhancing methane production (MEC-AD) is a new technology that has the potential to alleviate the energy crisis and greenhouse effect. With small input of electrical energy, it uses microorganisms as catalyst to decompose organic matter into electrons and protons at the anode while producing hydrogen and methane at the cathode. In recent years, MEC has made significant progress in reactor configuration, cathode material, electron transmission method and the composition of microbial community structure. Among them, high-efficiency and low-cost cathode catalysts, which attracts researchers' attention, is crucial in transforming the idea of MEC into practice. This article reviewed the working principle of MEC-AD in biomethanation and the development status of cathode catalyst including carbon-based cathodes, metal-based cathodes and composite cathodes. The methane yield, electrochemical characteristics, biocompatibility, electron transmission method and microbial community structure of different cathode systems were systematically introduced, compared and discussed according to their advantages and disadvantages. Potential future research directions were pointed out to provide the basis for the engineering application of the MEC-AD technology.

Functionalized polyolefin is a modified product of polyolefin that can be applied to multiple fields, such as adhesion, energy and packaging. It is generally prepared by grafting, cross-linking, copolymerization, etc. Based on the large scale and low price of polyolefin, polyolefin grafting modification directly introduces the wide range of functional groups onto a polyolefin backbone by radical-induced grafting, which is the most economical and convenient. Due to the differences of reaction condition, polyolefin graft modification can be divided into solution grafting, melt grafting, irradiation grafting, solid phase grafting and suspension grafting. In the process of graft modification, the grafting degree and grafting efficiency are affected by many factors, such as polyolefin type, grafting monomer, initiator, comonomers and reaction conditions. This paper reviews the research progress of the grafting methods, the advantages and shortcomings of different grafting methods and analyzes the influence factors in the process of graft modification. According to the controllable free radical grafting modification and metal catalyzes modification of polyolefins, as well as the application of functionalized polyolefins, the controllable modification of functionalized polyolefins and large-scale production are prospected.

Volatile organic compounds (VOCs) emission has caused serious atmospheric environment pollution in China. As the industrial VOCs emission has the characteristics of low concentration, large air volume, and water containing, the adsorption treatment with molecular sieve becomes very important. The factors affecting molecular sieve adsorption of VOCs are the pore structure, surface properties, hydrophobicity and so on. The results show that the adsorption performance of the molecular sieves with the pore size matching the kinetic size of the adsorbate and hierarchical structure is good, and the introduction of appropriate compensating cation can also enhance the adsorption. The mainstream of current development includes to increase the silicon to aluminum ratio, to improve the hydrophobicity of molecular sieve by silanization modification, to avoid using template agent, and to reduce costs and pollution. It has become a new topic to realize green synthesis to reduce the energy consumption by replacing the traditional hydrothermal synthesis method by solid phase method, microwave assistance and seed introduction. Research and development of multi-functional integrated materials and combination of adsorption with other methods to deal with VOCs has become the future trend.

Deep, low permeability and high closure pressure reservoir will be the main area of hydraulic fracturing in oil and gas fields in the future. Ceramic proppant has attracted much attention because of its role in supporting fractures, improving conductivity and increasing oil and gas production in hydraulic fracturing. With the depletion of high-grade bauxite resources, low alumina materials have become the main raw materials for the preparation of ceramic proppant. At present, it mainly includes low-grade bauxite, silicoaluminic solid waste and other materials. Based on a large number of literature, the advantages of ceramic proppant prepared from low aluminum materials and the defects of insufficient strength were described. In order to solve this problem, two kinds of strengthening methods were proposed: coating enhancement and additive enhancement. The effects of precuring, curable, liquid phase and distorted lattice on the strength of ceramic proppant were discussed. On this basis, the optimal reinforcement way of ceramic proppant for different raw material preparation and different application environment were summarized. Finally, the potential development direction of ceramic proppant in the future was prospected.

Recently, unidirectional water/oil transport materials with unique spontaneous liquid motion have become a hot issue. As a new type of materials, unidirectional water/oil transport porous materials can be used in various fields such as fog collection, oil-water separation, microfluidic transmission and functional fabrics. Compared with normal porous membranes with homogeneous wettability, the wettability gradient of unidirectional liquid transport three-dimensional porous materials can be accurately designed in the surface and along the material thickness, which can provide driving force, promote the directional transportation of liquids, and improve the transport efficiency without additional energy. This paper gave a comprehensive review to the recent studies about unidirectional water/oil transport porous materials with wettability gradient based on the principles of chemical gradient, roughness gradient and pore size gradient. In each part, the preparation, types of transporting liquid and unidirectional transport process were discussed according to eight methods. Moreover, the application of this kind of materials in moisture-wicking fabrics, fog collection and oil-water separation were summarized. Finally, the challenges and prospects in design and application of this kind of materials were highlighted.

Commercial activated carbon (AC) was used to adsorb binary mixed dyes of methylene blue (MB) and Carmine (AR18) to prepare AC/(MB+AR18) electrode materials. The electrochemical performance of activated carbon (AC) and that adsorbed different concentration binary mixed dyes [AC/(MB+AR18)] was compared. The test results of the three-electrode system showed that, in 1mol/L H₂SO₄ electrolyte and under the current density of 1A/g, the specific capacitance of AC/(MB+AR18) after adsorbing in a concentration of 400mg/L pollutants was 182F/g, higher than that of the single AC (109F/g). Subsequently, AC/(MB+AR18)-400 with the best performance was selected as the electrode material to assemble a symmetrical supercapacitor device. It is found that the operating voltage window of AC/(MB+AR18) was increased to 1.5V, compared to 1.1V for the symmetrical supercapacitors assembled with AC only. When the current density was 0.75A/g, the power density was 843.84W/kg, and the energy density reached 32.23W·h/kg, higher than that of the supercapacitor assembled by activated carbon (4.74W·h/kg), which suggested that MB and AR18 not only provided additional Faraday capacitance for AC, but also helped to increase its operating voltage window.

The lightweight of automobile is a global problem. The large tow carbon fiber (CF) reinforced composites with low cost are considered to be an important way to realize the lightweight and structured of automobile. However, for the liquid forming process of large-tow CF, the micro-wetting in the fiber bundle is usually difficult because of too many filaments in a single bundle, which may lead to defects such as dry spots and bubbles. At the same time, the traditional automobile electrophoresis drying process also poses a challenge to the high temperature performance of composites. In view of this, the fiber permeability test and the simulation and optimization of vacuum assisted resin transfer molding (VARTM) for automobile floor were carried out by using 0°/90° biaxial stitching of large-tow CF cloth and high temperature resistant epoxy (EP) resin. The forming mold was designed and manufactured, and the automobile floor sample was trial-produced successfully. The observation of super depth of field microscope showed that the fiber bundles and interlayers were infiltrated well, and there were no obvious defects. High temperature on-line tensile and strain test indicated that temperature had a significant effect on tensile modulus but little effect on strength, and the strain recovery ability was good at 180℃, which revealed that the composites still had excellent strength and creep resistance at high temperature. The results were of great significance to guide whether the composites could pass the traditional electrophoretic drying process of automobile.

Lithium-oxygen (Li-O₂) batteries are considered as the most promising new generation energy storage devices because of their high theoretical energy density and environmental friendliness. However, large overpotential, low practical energy density and poor cycle life are the huge obstacles to their practical application. Since the insoluble and insulating discharge products (Li₂O₂) gradually form on the surface or in the pores of cathode during the discharging process, these products will block the diffusion channel of O₂/electrolyte and cover the catalytic active sites. In addition, the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) require noble-metal-based materials as catalyst to reduce the overpotential and achieve high electrochemcial efficiency. However, high cost and scarcity of the noble-metal catalysts hinder their large scale applications. Development of economically viable and highly efficient noble-metal-free electrocatalysts is extremely urgent, especially for heteroatom-doped carbons as the most promising candidates. In this paper, a novel Co, N and S co-doped three-dimensional self-standing porous carbon (wd-NSC) was prepared as cathode for Li-O₂ battery using melamine and thiourea as nitrogen and sulfur sources via one-step pyrolysis of paulownia wood in NaCl/CoCl₂ mixed molten salt medium. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results found that the wd-NSC inherited the original vertical channel structure of paulownia wood, and formed porous carbon fiber network on the surface and inside the channels of wd-NSC. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) confirmed that N and S were successfully doped into the C skeleton, while Co might exist in the form of single atom or clusters. Nitrogen adsorption/desorption isotherms showed that the wd-NSC possess hierarchical porous structure with pore sizes ranging from micropore to macropore. Raman spectra certified that the introduction of S increased the defect degree of wd-NSC. At a current density of 0.05mA/cm², the discharge specific capacity of wd-NSC reached to 12.83mA·h/cm², and exhibited a good rate capability and cycling stability (at a current density of 0.1mA/cm² and a limited capacity of 0.5mA·h/cm², the cell can maintain 125 cycles). The excellent electrochemical performance of wd-NSC in the Li-O₂ battery could be attributed to the synergistic effect of three-dimensional hierarchical porous structure and Co, N, S heteroatoms co-doping. The above results demonstrated that this study provided a promising strategy to produce efficiency and low-cost cathodes for practical application in Li-O₂ batteries.

Phase change microcapsules were prepared with paraffin as the core and gelatinized flour as the shell via adsorption deposition method. The chemical composition, morphology, thermal performance of the phase change microcapsules were characterized by the Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetric analysis and differential scanning calorimetry. The results showed that the microcapsules were ellipsoidal with particle sizes of 400—600nm, and the peak phase change temperature, latent heat and coating rate were 22.2℃, 110.5J/g and 66.7%, respectively. The microcapsules had good chemical and thermal stability. Phase change gypsum was prepared by adding the phase change microcapsules into gypsum matrix. The results demonstrated that the mechanical strength of the phase change gypsum decreased with the content of microcapsules, and adding wet microcapsules could reduce the mechanical strength loss. In a 5-month continuous endothermic and exothermic experiment, the phase change gypsum materials had no leakage and obvious thermal performance degradation. In summer afternoon, the internal temperature of the model phase change building decreased by 4.1℃ as compared with the external temperature. It showed that the phase change gypsum materials have certain temperature control ability.

A cross-linked waterborne polyurethane solid-solid phase change material (WPUPCM) was prepared with polyethylene glycol 2000 (PEG2000) as the soft segment, isophorone diisocyanate (IPDI) as the hard segment, and glycerol (GL) as the chain extender. Firstly, the effects of monomer molar ratio and soft segment content on thermal storage performance and phase transformation morphology of WPUPCM were discussed. Then, the chemical structure, microstructure, crystallization performance, thermal stability and cycle stability of the prepared WPUPCM were tested and analyzed by infrared spectrometer, atomic force microscope, polarizing microscope-heat table system, thermogravimetric analyzer and differential scanning calorimetry. Finally, the temperature regulation performance of heat storage and temperature regulation textiles after WPUPCM treatment was discussed. The results indicated that the monomer molar ratio and soft segment content had a great influence on the heat storage performance and phase transformation morphology of WPUPCM. Reducing the soft segment content and increasing the proportion of chain extender were conducive to the reduction of the melting temperature of WPUPCM. When the monomer molar ratio of PEG, IPDI and GL was 1∶1.8∶0.5, the melting temperature of the prepared WPUPCM was 35.52℃ with a high melting enthalpy of 89.75J/g, which can well satisfy its application requirements in the textile and clothing field. Compared with pure PEG, the prepared WPUPCM had a homogeneous nucleation crystallization mechanism. Due to the constraint of the hard segment, the crystallization rate of WPUPCM slowed down, the size of the spherulites became smaller, and the stability of the spherulites was improved. The study also showed that the prepared WPUPCM had good thermal stability, cycle stability and good temperature regulation performance.

The lignin-based porous carbon material (LPC) was obtained by using lignin as raw material and tube furnace reactor through a one-step pyrolysis-activation method. Nitrogen adsorption (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the physical and chemical properties of porous carbon material. At a constant carbonization temperature of 900℃ with CO₂ concentration of 6% and water vapor concentration of about 20%, the surface of LPC-C₆S₂₀ had a good nanostructure, and the total pore volume and specific surface area reached 0.77cm³/g and 1497.51m²/g, respectively. The activation atmosphere promoted the uniformity of porous carbon material particles and the formation of micropores and mesopores. The LPC sample contained abundant surface functional groups such as —OH, C—H, C＝C, C—O, C＝O, CO—C, C—N and C＝N, etc. As the concentration of the activator changed, these functional groups remained relatively stable. Therefore, the sample obtained by this method had a good nanostructure with a larger pore volume, specific surface area and functional groups.

In order to explore the synergistic drag reduction effect of composite system of cationic surfactant and polymer, the cationic surfactant cetyltrimethylammonium chloride (CTAC) and polymer polyacrylamide (PAM) were as the research objects. The multi-functional turbulent drag reduction experimental apparatus was designed and built, which was applied to study the effect of polymer ion type on the synergistic drag reduction of the compound system, optimize the compound system and analyze the effect of surfactant concentration/polymer concentration on the synergistic drag reduction of the compound system. The experimental results showed that synergistic drag reduction effect of different ion types PAM and CATC/NaSal compound system was presented as CPAM>AmPAM>NPAM>APAM and the CPAM-CTAC/NaSal was the optimal compound system. When the CTAC/NaSal concentration was 0.3g/L of PSP, the synergistic drag reduction effect of the CPAM-CTAC/NaSal compound system was the strongest, the DR and shear resistance reached its peak, and the average drag reduction rate was as high as 69.22%. When CTAC/NaSal increased to 0.5g/L, the average drag reduction rate quickly decreased to 10.08%, the critical generalized Reynolds number of the compound system also quickly dropped to 7535.20, and the shear resistance was weakened. As the CPAM concentration increased from 0.05g/L to 0.2g/L, the drag reduction rate in the drag reduction damage zone can increase from 9.08% to 57.49% with increasing critical generalized Reynolds number from 31272.43 to 45033.36, and the shear resistance was enhanced. When the CPAM concentration exceeded the second critical association concentration (CAC Ⅱ) 0.15g/L, the increasing trend of the drag reduction rate in the damage zone of drag reduction and shear resistance slowed down. In addition, compared with a single drag reducer, the temperature resistance of the compound system was significantly enhanced and the maximum drag reduction efficiency at 55℃ was increased to 69.05%.

Humidity sensitive materials are crucial for the humidity sensors. In this study, a novel idea of combing two biomass products with unique chemical structures, cellulose and agar, to prepare nitrocellulose nanocrystals/agar (NCNCs/Agar) composite sensitive film materials with different humidity sensitivity was presented. Based on the above-mentioned sensitive film materials, a high sensitivity quartz crystal microbalance (QCM) humidity sensor was developed. The results revealed that the sensitivity and frequency response of the NCNCs/Agar-based QCM humidity sensor were significantly higher than those of the sensor based on a single-component sensitive film. The results confirmed that the humidity sensor with NCNCs/Agar (optimum NCNCs to agar mass ratio of 1∶25) loading of 2.049μg (QCM-b) exhibited the excellent performance. In addition, the sensor showed excellent linearity (R² =0.9933) in 11%—84% relative humidity (RH) and high sensitivity (32.54Hz/%RH). In 11%—97% RH, the humidity sensor showed high response value (-5820Hz), excellent logarithmic linearity (R² =0.9994), short recovery time (5s), good reproducibility and long-term stability. In conclusion, these results indicated that the NCNCs/Agar-based QCM sensor demonstrated great promise for practical use in humidity detection.

In order to improve the thermal resistance and electrolyte affinity of separators for lithium-ion batteries, a composite separator (PPCS) based on polyethylene terephthalate (PET) nonwoven and polyacrylonitrile (PAN) resin was prepared by the phase inversion method. The physical-chemical properties and battery performances of PPCS were systematically characterized, such as the structure, tensile strength, electrolyte property and thermal resistance as well as the charge-discharge performance. The results indicated that PPCS had a uniform microporous structure with an average pore diameter of about 425nm and a porosity of 74%, and its tensile strength was up to 30MPa. Compared with commercial separators, PPCS exhibited better electrolyte properties (electrolyte uptake of 365%, contact angle of 0°) and higher ion conductivity (1.65mS/cm). Meanwhile, this composite separator possessed superior thermal stability with a shrinkage ratio of about 0 at 150℃ for 0.5h. Based on the above advantages, lithium cobalt oxide/Li cells assembled with PPCS exhibited good battery performances. For example, the discharge capacity retention was 95.2% after 200 cycles at 0.2C and the discharge capacity retention at 10C was 58.3% of that at 0.5C. Thus, this composite separator showed a good application prospect for next-generation lithium-ion batteries.

The slow oxygen-limited pyrolysis of attapulgite (ATP) and alkali lignin (AL) was used to prepare biochar/attapulgite (BC/ATP) for the adsorption of sulfadiazine (SDZ) in water. The effects of feedstock ratio and pyrolysis temperature on the content of BC/ATP product composition and adsorption performance were investigated, and the effects of initial pH, BC/ATP dosage, adsorption time and initial SDZ concentration on the removal rate were also investigated. The kinetics of the adsorption process was fitted with the proposed pseudo-first-order, pseudo-second-order and intraparticle diffusion equations, respectively, and the isothermal adsorption curves were fitted with the Langmuir and Freundlich equations. The surface morphology, pore structure and functional groups of BC/ATP were analyzed by SEM, FTIR, XRD, Raman and BET determination. The results show that ATP can effectively promote the secondary pyrolysis of volatile intermediates during pyrolysis, increase the BC yield, improve the BC/ATP adsorption properties, and broaden the pH sensitivity of BC/ATP through the metal ion effect of ATP. The adsorption kinetics of the different composites satisfies the pseudo-second-order kinetic model, and the fitting by the intraparticle diffusion model indicates that this diffusion behavior is not the only factor limiting the adsorption rate, and the isothermal adsorption curves are more consistent with the Langmuir isothermal adsorption model, 0 < R_L < 1, for preferential adsorption, indicating that the adsorption process is easy to proceed with a maximum adsorption capacity of 109.53mg/g. The adsorption mechanism under different pH conditions can be divided into two parts: ① under acidic and neutral conditions, it mainly relies on the electrostatic interaction between the negative charge on the upper BC surface of BC/ATP and SDZ; ② under alkaline conditions, it mainly relies on the metal cation bridging interaction between the metal ions on the surface of ATP and the hydrogen bonding of SDZ.

Apparently, the catalytic reaction of sugar is of great significance to human life activities and industrial production. In recent years, the rapid development of the multienzymes co-immobilization technology provides a green and efficient research tool for the catalytic reaction of sugar. Under this background, combined with the multienzymes cascade reaction in sugar catalysis, this paper systematically expounds the traditional and new methods of multienzymes co-immobilization, and illustrates its respective principles and advantages as well as disadvantages. On this basis, this paper further introduces the wide applications of multienzymes co-immobilization technology in sugar catalysis in detail, such as starch hydrolysis, cellulose utilization and functional sugar synthesis. In accordance with the related research results, it is indicated that the multienzymes co-immobilization technology not only has a series of remarkable characteristics including high efficiency catalysis, strong stability and easy separation, but also can give full play to the advantages of synergistic catalysis among multienzymes, thus greatly promoting the catalytic reaction of sugars. In the last, this paper analyzes some of the problems and challenges facing multienzymes co-immobilization technology, puts forward some research thoughts and methods for solving these problems，and looks forward to its development prospects.

Softening treatment of water is a process to remove calcium, magnesium and other soluble salts in hard water. It is a crucial link in the engineering operation of desalination and salt resource utilization process as well as in the process of drinking water safety guarantee. In this paper, the basic principles of the pressure-driven membrane process represented by salt separation nanofiltration and the electric-driven membrane process represented by selective electrodialysis in water softening were introduced. The research progress of related technologies in water softening process was reviewed. The technical characteristics, advantages and disadvantages of various membrane water softening systems were analyzed in detail. The comparison between salt separation nanofiltration and selective electrodialysis was made, and the possible research directions of membrane water softening technology in the future were prospected.

Sewage is a carrier of resources and energy, containing enormous chemical and thermal energy. Traditional sewage treatment processes use energy to eliminate pollutants, which consumes high energy and releases greenhouse gases. In the context of carbon neutrality in China, urban sewage treatment plants achieve carbon-neutral operation with the potential in energy self-sufficiency, greenhouse gas reduction, etc., which has become a hot spot for urban sewage treatment plant transformation. Based on the analysis of the carbon-neutral operation potential of urban sewage treatment plants, this article analyzed a new type of wastewater treatment technology with carbon capture and low-consumption such as HRAS, CEPT, autotrophic nitrogen removal and denitrifying phosphorus removal. The energy recovery technologies utilizing anaerobic digestion combined heat and power while heat energy recovery and solar energy recovery were also elaborated. The application advantages and effects of urban sewage treatment plants operated by carbon-neutral technology at home and abroad were discussed. Meanwhile, findings from this study suggested that low-consumption operation and energy recovery were the key to achieving a carbon-neutral operation in urban sewage treatment plants, and prospects were put forward for achieving carbon-neutral operation in urban sewage treatment plants, aiming to provide reference for the low-consumption and sustainable development of urban sewage treatment plants.

As the main source of the fluorescence of plant cell walls, lignin is a natural macromolecular fluorescent material. However, the elusive luminescence mechanism and regulation behavior have seriously hindered the high-value application of lignin fluorescence. In this review, the research progress of lignin fluorescence was summarized in terms of the chemical structure and coupling state of lignin fluorophores. Meanwhile, the research strategy for lignin fluorophores and the scientific problems existing in this field were also summarized, respectively. Firstly, due to the inner - filter effect and the existence of fluorescence quenchers in lignin, it was inconclusive to conclude the chemical structure of lignin fluorophores by comparing the fluorescence intensity and emission wavelength between model compounds and lignin. Secondly, it was limited to analyze the chemical structure of lignin fluorophores alone because of the interactions between lignin fluorophores. The real luminescent group of lignin was the aggregation coupling state between these fluorophores. Furthermore, based on the study of lignin microstructure aggregation behavior and aggregation-induced luminescence theory, the effect and mechanism of lignin aggregation behaviors, including inter-and intra-micellar aggregation, on their fluorescence were clarified from macroscopic aspects. Future research should focus on the optimization of the correlation model of lignin aggregation and fluorescence behavior. Meanwhile, the coupling mechanism between lignin fluorophores should be uncovered from the molecular level. Finally, it was believed that lignin fluorescence was not only simply a study of the photophysical property but also a comprehensive investigation including the chemical structure, microstructure regulation and excited-state energy transfer of lignin. There was still a lot of challenging work to get insights into the mechanism of the fluorescence of lignin, which would further promote the study of lignin in other directions.

Aerobic granular sludge has a broad application prospect in the field of wastewater treatment due to its advantages of dense structure, good settlement and impact load resistance. However, the long forming time of particles and the instability of long-term operation have become the limiting factors of its promotion and application. The research progress on the stability of aerobic granular sludge at home and abroad in recent years was reviewed. The factors affecting the operation stability of aerobic granular sludge were analyzed, including the macroscopic reactor configuration, water flow shear force, organic load, sate-starvation period, underwater inflow, C/N ratio, F/M ratio, and the microscopic particle size, extracellular polymer composition, microbial growth rate, colony structure, etc. The methods of enhancing the stability of aerobic granular sludge, such as adjusting aeration, changing feeding methods, adding carrier particles and selecting slow-growing microorganisms, were listed and discussed. Finally, it pointed out that the formation mechanism of aerobic granular sludge will still be the focus of future research. At the same time, genomics tools should be used to explore the relationship between the effect of microbiota sensitivity on particle stability, and the optimal operating conditions of aerobic granular sludge should be determined in the combination with microbial ecology, in order to promote the application and development of this technology.

Heating by wastewater source heat pump (WWSHP) is an important way for urban sewage heat utilization. In order to improve the energy efficiency of the original WWSHP unit in recovering urban sewage waste heat, the heating system of the backwash falling film WWSHP unit was proposed, which can be compared with the heating performance of the full liquid WWSHP unit. The sewage backwash system was also designed to reduce primary sewage blockage in the direct heat exchange WWSHP. Experimental results showed that the average overall heat transfer coefficient (OHTC) of the wastewater falling film evaporator (WFFE) was significantly higher than that of the wastewater flooded evaporator (WFE). The average OHTC of the WFFE was 60.17% higher than that of the WFE. Under the working conditions tested, the heating performance coefficient of the WWSHP with WFFE was significantly higher than that with WFE. The average coefficient of performance in falling film mode was 9.52% higher than that in the flooded mode. The wastewater backwash can solve the blocking problem of direct heat exchange primary WWSHP unit. When using the backwash mode, the time interval for backwashing should be as short as possible to ensure that the average heat transfer coefficient will not decrease. Therefore, the WWSHP unit using the backwash falling film evaporator can use the sewage heat more efficiently.

Proper treatment of polyvinyl chloride (PVC) waste is challenge as it is not easily degraded and incineration can lead to environmental issue as it will produce toxic chemicals. In this study, a hydrothermal carbonization approach was applied to treat PVC waste. The influence of exogenous additives on dechlorination efficiency of PVC were evaluated. The results showed that, with exogenous additive, substitution, elimination, dehydration and aromatization reaction were enhanced during hydrothermal carbonization. The maximum dechlorination efficiency of 97.50% was achieved with the mass ratio of 1.4% between rice straw and PVC resin at hydrothermal carbonization temperature 240℃ for 120min. The calorific value of hydrothermal charcoal was relatively higher (39.57MJ/kg ± 0.40MJ/kg), indicating a good combustion process. This study presented a novel and sustainable approach, which could convert PVC-waste as a form of solid fuel.

The PVDF-PFTS/SiO₂ superhydrophobic composite membrane was prepared by surface grafting technology. The surface structure and the composition of the membrane before and after contamination were analyzed by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). The change of the effluent conductivity and membrane flux of the device in direct contact membrane distillation (DCMD) was investigated. The anti-mixed fouling performance and mechanism of the superhydrophobic PVDF-PFTS/SiO₂ superhydrophobic composite membrane were analyzed by XDLVO theory. The results showed that under the combined action of 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane (PFTS) and SiO₂, a micro-nano composite papillary structure was formed on the surface of the PVDF-PFTS/SiO₂ superhydrophobic composite membrane. The water contact angle (WCA) increased from 99° to 155°. Compared with the PVDF base membrane, the PVDF-PFTS/SiO₂ superhydrophobic composite membrane had a better anti-fouling performance against mixed pollutants. After 10h continuous operation, the membrane flux and rejection rate were maintained at 10.06kg/(m²·h) and 99.80%, respectively. The theoretical analysis of XDLVO showed that the transformation of the force between the surface of the PVDF-PFTS/SiO₂ superhydrophobic composite membrane and the pollutants from gravitational force to repulsive force was one of the main reasons for its enhanced anti-mixed fouling performance.

As a new CO₂ utilization technology, carbonation curing can not only recycle industrial solid wastes, but also sequestrate greenhouse gases permanently, which has attracted more and more attention in recent years. However, due to the complex compositions of raw materials and diverse curing processes, the assessment methods for CO₂ uptake ratio are different. Thus, it is urgent to form a universal assessment method suitable for different concrete products and curing processes. After comparing many assessment methods of CO₂ uptake ratio, a new weight gain and oven-dry method with good applicability and operability and a new basis based on the revised mass of reactive compositions have been proposed. Based on the Steinour formular, the inert compositions in calcium and magnesium components are further deducted, which can help for reasonable assessment of the effective reaction degree of reactive compositions. For cement paste samples, results showed that oven-dry method could compensate the error caused by water evaporation more reasonably, and it was suitable for industrial-scale CO₂ uptake ratio evaluation. For solid waste concrete samples, results showed that the basis of modified reactive compositions mass reflected the carbonation degree of the reactive compositions, and the influences of moisture content and inert components were excluded. Finally, the assessment method proposed in this paper was used to evaluate the CO₂ uptake ratio of carbonation-cured concrete in the industrial demonstration of Jiaozuo, Henan, which provided a more reasonable method of the carbonation curing technology.

Hydrothermal treatment (HTT) was conducted in this study to post-treat the food waste digestate (DFW). The mass flow and energy feasibility of the whole process were analyzed based on the experiment results. Results showed that the dewaterability of DFW was improved by hydrothermal treatment. The yield and moisture content of DFW cake were reduced. Temperature was the most important factor that affects the performance of HTT. At the HTT temperature of 200℃, the yield and moisture content of DFW cake decreased from 71.83kg/t DFW and 88.43% to 22.11kg/t DFW and 76.30%, respectively. The reduction in DFW cake yield and moisture content would decrease subsequent transportation and drying costs significantly. In addition, the hydrothermal process promoted the transfer of DFW organic substances from solid to liquid phase. After coupling with the anaerobic digestion treatment, methane can be produced to effectively recover the energy from liquid phase. A comprehensive calculation on material and energy balance for the DFW treatment process was carried out. The increase of the hydrothermal treatment temperature increased the input of heating energy, but reduced energy input of the subsequent thermal drying process, and increased methane production of DFW liquid products. When HTT temperature and holding time were 160℃ and 60min, the net energy input of the entire treatment process was the least (30.75MJ/t DFW), and 106.48MJ/t DFW was saved compared to the technology without hydrothermal treatment. The recovery rate of heating energy consumption in the hydrothermal process, the moisture content of DFW cake, and the methane production potential of the liquid phase were the main factors that affect the energy balance of the entire process, and were the main directions of process optimization.

The remediation of organic chlorine contaminated soil is currently a significant and sticking point in soil remediation. For the trouble of hard degradation in organochlorine, soil column leaching was used to simulate in-situ remediation and peroxymonosulfate-ferrate-FeS (PFI) oxidation system was used to remediate o-dichlorobenzene contaminated soil. The soil column experiment was used to test the permeability coefficient (1.46×10^-4~2.46×10^-4cm/s) of the compound peroxymonosulfate and potassium ferrate solution in the soil. It was found through experiments that as the oxide concentration increased, the permeability coefficient became smaller. The PFI was used in soil column leaching remediation experiments on contaminated soil. It showed that the oxidation and remediation of deep soil could be achieved by PFI. The final residual ratio of o-dichlorobenzene in the soil at 5cm, 15cm and 25cm depth were reduced to 17.5%, 20.0% and 30.3% respectively by leaching at a middle concentration for 3.8h. In terms of changing soil properties, soil column experiments showed that the change of soil properties by PFI had a negative correlation with soil depth. The shallower the soil, the more thoroughly the soil properties changed. In summary, the PFI oxidation system has good prospects for the remediation of chlorobenzene-containing organic contaminated sites.

In this paper, a simulated groundwater polluted by aniline (AN) was treated continuously in a sand column. The removal effect and environmental risks of three persulfate (PS) activation methods on AN were studied. The activators were alkali (NaOH), iron (Fe²⁺) and hydrogen peroxide (H₂O₂). Results showed that H₂O₂ activated PS treatment had the best removal effect on AN. Cumulative removal rate of AN reached 60% within 4 days. When H₂O₂ concentration decreased, the cumulative removal rate of AN reached 83% within 4 days, which could overcome the problem of oxidant waste in constant concentration injection. The total organic carbon (TOC) mineralization rate of each treatment was far less than the AN removal rate, indicating that a lot of AN was not completely degraded. GC/MS analysis showed that the degradation products mainly included p-benzoquinone, azobenzene and straight-chain alkanes. Alkali activation significantly increased the pH of the system, while other reaction systems were all neutral, and pH decreased after reaction. The REDOX potential of PS activated by H₂O₂ was stable and maintained a high level. The acute toxicity of different treatments was higher than before the restoration, which was mainly because the residual sulfate after the decomposition of sodium persulfate made the groundwater saturated zone form a high-salt zone. Therefore, in situ injection of activated persulfate for remediation, the risk of secondary contamination should be strictly assessed and controlled.

The template method was used to prepare sulfur-doped mesoporous carbon sorbents with the template agent of MCM-41 and the precursors of 2-thiophene ethanol and thymol blue. Mercury removal performance of sorbents was studied in a fixed bed experimental device and the effects of precursor mass ratio, calcination temperature, flue gas temperature and composition (O₂, SO₂) on mercury removal were investigated. The physical and chemical properties of the sorbents were characterized to analyze the mercury removal mechanism. The results showed that when the precursor (2-thiopheneethanol∶ thymol blue) mass ratio was 6?∶?1 and the calcination temperature was 900℃, the prepared MCM-900-1∶6 displayed the highest mercury removal rate. The specific surface area of the MCM-900-1∶6 was 932m²/g and the contents of C and S were 81.12% and 10.24%, respectively. The MCM-900-1∶6 had a wide temperature range of mercury removal, and the mercury removal efficiency was as high as 90% at 50—150℃. The MCM-900-1∶6 indicated a good resistance to SO₂, and O₂ somewhat promoted mercury removal. With rising calcination temperature, the layering phenomenon disappeared and the mesoporous carbon became more regular. FTIR analysis showed that after calcination at 900℃, the C＝S replaced O－H to become the most abundant functional group. XPS analysis found that the sulfur on the mesoporous carbon surface was thiophene sulfur and elemental sulfur, which played a major role in mercury removal.

Effective treatment of rural organic domestic waste (ROW) is of great significance to beautify the rural environment. It is prone to acidification and ammonia nitrogen inhibition during high-concentration anaerobic digestion, resulting in poor stability of the system. There is still a lack of research on the effects of different ROW co-digestion substrates and TS(total solids) concentrations on anaerobic digestion. In order to improve the performance of anaerobic digestion and reduce the pressure of environmental protection, the anaerobic co-digestion characteristics of ROW under different substrate ratio and different TS concentration were studied, so as to optimize the anaerobic fermentation process of ROW. The anaerobic co-digestion with different feed concentration was carried out. ROW was collected from Peixian, Xuzhou, Jiangsu Province, and the PM and RC were from the Luhe Animal Experimental Base of Jiangsu Academy of Agricultural Sciences. When the digestion substrates were ROW and PM, the cumulative methane yields increased with the increase of feed TS concentration, and the highest was 257.38mL/g VS. When the digestion substrates were ROW and RC or ROW, PM and RC, the cumulative methane yields increased when the feed TS concentration increased from 8% to 12%, and the highest were 339.59mL/g VS and 322.16mL/g VS, respectively; when the feed TS concentration continued to increase to 15%, the methane yields decreased and were 231.17mL/g VS and 194.67mL/g VS, respectively, which were lower than that of other experimental groups. Under the experimental conditions set in this paper, the optimal co-digestion feed was as follows: the digestion substrate was ROW and RC, VS ratio was 1∶1, the feed TS concentration was 12%, and the cumulative methane yields was 339.59mL/g VS.

Nano hydroxyapatite were prepared from calcium hydroxide and sodium dihydrogen phosphate. The yttrium/hydroxyapatite composite were prepared by chemical precipitation method. The composite materials were characterized by numerous techniques including SEM-EDS, XRD and FTIR. The effects of loading ratio, pH, adsorption time and initial concentration on the adsorption performance of phosphate were investigated by static adsorption experiment. The results showed that the nano-hydroxyapatite was uniformly dispersed rice-like particles, and the XRD pattern showed that the nano-hydroxyapatite was typical. Yttrium/hydroxyapatite particles agglomerate and become larger. The intensity of characteristic peaks decreased, but no new strong characteristic peaks appeared. Adsorption studies showed that when molar mass of calcium and yttrium was 2∶1, the adsorption efficiency was the highest. The adsorption capacity of the composite increases with the increase of the initial concentration, and the maximum adsorption capacity was 116.38mg/g. The adsorption process was in accordance with the quasi-second-order kinetic model, the two-chamber first-order kinetic model and the Freundlich isothermal adsorption model. With the increase of pH in the range of 3—9, the adsorption efficiency of composites increases first and then decreases, and then reaches the maximum when pH was 5—6.

The efficient and low consumption separation of oil and suspended solids (SS) from refinery wastewater is related to the green development of the petrochemical industry and the goal of pollution and carbon reduction. A combined particle microchannel separation bed was constructed by combining hydrophilic and lipophilic granular media to realize the collaborative separation of oil and SS. A novel separation method was developed subsequently by coupling the depth filtration and hydrocyclone-intensified regeneration. The separation performance of combined granular media microchannel separation on the SS and oil was verified by lab-scale and pilot-scale tests. A physical pretreatment engineering project scheme was proposed for the electric desalting wastewater of a refinery in Sinopec, and the economic difference between the physical pretreatment process and the traditional process was compared and analyzed. The high-speed camera visualization test showed that oil droplets were effectively captured by the combined granular media, and the introduction of hydrophilic particles had no negative impact on the oil removal performance. In view of the actual petroleum refinery wastewater with dramatic fluctuations in oil and SS concentrations, the oil and SS concentrations can be stably controlled within 20mg/L and 50mg/L respectively after treated by the capacity of 1m³/h separator. Meanwhile, the long-term continuous stability of the effluent was also verified by the pilot-scale test. Compared with the traditional pretreatment process of, the physical pretreatment process eliminates the consumption of PAC and PAM, and avoiding the generation of hazardous wastes such as flotation slag, which reflects the economic and environmental advantages.