The quality upgrade of automotive gasoline is a major national demand at the turn of the century. Facing this challenge, China’s oil refining industry has independently designed a proper technology development strategy, proposed the maximizing iso-paraffins (MIP) technology, and developed a series of technologies and corresponding technical routes adapted to the gasoline production at different emission regulation stages. This paper reviewed the international environment at the beginning of the birth of MIP technology, the problems faced by domestic catalytic cracking technology at that time and the role of MIP technology in the process of gasoline quality upgrading and technology development strategies. On this basis, the relevant researchers closely followed the market demand, continuously absorbed emerging technologies to achieve continuous updates of MIP technology, and thus kept it strong competitive in the market. Based on market demand, the continuous upgrades of MIP technology kept it strongly competitive. The experience and enlightenment of the successful development and large-scale application of MIP technology were expected to become a paradigm of China’s route of scientific and technological self-reliance.

At present, the methanol production capacity is close to 98 million tons and the output is 80million tons. The apparent consumption of methanol accounts for about 60% of the world total, and the self-sufficiency rate is more than 90%. However, the raw material pattern of methanol production, supplemented by natural gas and coke oven gas, leads to the annual CO₂ emission of 200 million tons. Under the background of carbon neutrality, with the in-depth development of flue gas CO₂ capture represented by the power field and the continuous increase of the installed scale of green electricity, more and more CO₂ and green electricity will exist in the form of products. The comprehensive cost of capturing a ton of CO₂ reaches about 300 yuan. Under this cost boundary, if the CO₂ captured cannot be recycled to bring benefits. Therefore, how to convert and utilize CO₂ has become a research hotspot, and hydrogenation of CO₂ to green methanol is a good solution. Moreover, relevant research and industrial development have also gradually set off a boom. In this paper, six aspects of policy driving, technological advantages, carbon reduction effect, green electricity and CO₂ conversion consumption, market demand, methanol industry upgrading were analyzed, and the development of green methanol was considered to be one of the important and necessary measures to achieve the goal of carbon neutrality.

As an important vapor-liquid mass transfer equipment in chemical unit operation process, packed tower is a key equipment in distillation operation process because of its advantages of high mass transfer efficiency, lower pressure and low energy consumption. Liquid distributor is an important column internal in packed tower, and its structure form is directly related to the distribution of liquid phase in the tower, thus affecting the separation effect of packed tower. This paper systematically introduced the development status of liquid distributors. The influence of the distribution effect of liquid distributor on a packed column's separation efficiency was introduced, including natural flow distribution and radial distribution coefficient. And the theoretical research and design optimization process of various structural types of liquid distributors in the domestic and overseas were analyzed in depth. Then the applicable scenarios of different evaluation methods for various liquid distributors were summarized. Finally, an outlook on the development of liquid distributors was given to provide ideas for the development and design of liquid distributors.

The flow and heat transfer characteristics on the shell side of the wound tube heat exchanger are of great significance to the design and optimization of LNG/FLNG systems. To solve this problem, a two-phase flow boiling numerical model was established to predict the pressure drop and heat transfer coefficient in the shell side. The VOF model, the phase-change mass transfer model and the surface tension model were added to study the influence of different factors such as mass flow density and dryness on the flow and heat transfer characteristics at the shell side, and the experimental verification was carried out through the flow and heat transfer experimental platform of the wound tube heat exchanger, which proved that the simulation rules were in good agreement with the experimental results. The results showed that the pressure drop increased with the increase of dryness; the heat transfer coefficient decreased with the increase of dryness; the shell side refrigerant mainly presented columnar flow, droplet flow, gaseous flow and other flow patterns under different dryness. This study provideed a theoretical basis for the design and optimization of the coiled tube heat exchanger.

Para-xylene(PX) is one of the most crucial aromatic raw materials in petrochemical industry. It is urgent to develop a more low-cost and efficient PX production process due to the growing demand for PX. This paper introduced ultrasound into the PX crystallization process and analyzed the data of supersolubility, metastable zone width and induction period of PX under different working conditions. Based on the classical nucleation theory and the cluster coalescence model, the PX crystallization characteristics and the mechanism of ultrasound enhancement were investigated. The results showed that ultrasound reduced the metastable zone width and induction period of PX crystallization process, speeded up the crystal nucleation rate and prevented the explosion nucleation. When the supersaturation was below 1.055, the PX nucleation mechanism was heterogeneous nucleation, and when it was above 1.055, the PX nucleation mechanism was homogeneous nucleation. The crystal growth mechanism was continuous growth. In addition to lowering the critical nucleation radius and critical nucleation free energy of PX, ultrasound also reduced the surface entropy factor and interface tension that correlated to the two nucleation mechanisms and raised the system’s diffusion coefficient. When the ultrasonic power changed from 0 to 88W, the crystal nucleation rate constant increased by 22.4 times and the diffusion coefficient by 11.86 times, respectively. This study might enable future PX crystallization process improvements.

Premixed combustion experiments of n-heptane were carried out in a micro-burner, and three different combustion modes were studied: homogeneous combustion (HMC), heterogeneous combustion (HTC), and coupled combustion (CC) in which homogeneous combustion and heterogeneous combustion simultaneously occurred. The combustion characteristics were analyzed under the three combustion modes, including the stable combustion range, conversion rate, combustion efficiency, gas product distribution characteristics, wall maximum temperature and wall temperature characteristics of n-heptane with different input power (P=20—70W) and equivalent ratio (Φ=0.55—2.5). The results showed that the stable combustion range of CC mode is the smallest and was limited by both HMC lean combustion limit and HTC rich combustion limit. The conversion rate of n-heptane was higher in the HMC and CC combustion modes, and the conversion rate exceeded 90% when Φ≤1.6. The conversion rate of n-heptane was only 16%—31% under HTC condition, and the product had high CO₂ selectivity, while other combustible gases were almost absent. When Φ≥1.0, the combustion efficiency of CC was higher than that of HMC. The reason was that the content of incomplete combustion products such as H₂, CO, C₂H₄, and C₂H₂ was smaller in CC mode, and the content of CO₂ in complete combustion products was higher. The maximum wall temperature of the three combustion modes showed a trend of T_max-HMC＞T_max-CC＞T_max-HTC. CC combustion mode had no obvious hot spot, had longer reaction high temperature zone and more uniform wall temperature distribution, and had high combustion efficiency, which was of great significance for the practical application of thermoelectric system and thermal photovoltaic system.

As a promising material, ammonium carbamate can be decomposed under the temperature from 20℃ to 100℃, and the reaction enthalpy reaches the high value of 2010kJ/kg. The effects of various conditions on the decomposition process of ammonium carbamate were discussed, such as solution concentration, flow rate and the temperature of heat source. Results showed that the higher temperature of heat source and the longer residence time contributed to a higher rate of reaction conversion and decomposition. But the solution concentration was less sensitive to decomposition process. The average conversion rate and the reaction rate in the research range of flow rate were increased by 5—11 times and 2—4 times, respectively. And the upgrade of heat source temperature contributed to a 2—4 times increase in the average conversion rate. Based on the analysis, numerical simulation and response surface analysis were used to optimize the structural parameters of the reactor, such as spiral radius, tube diameter and the number of turns. After structure optimization, the average conversion rate could be increased to 50.3%, and a reactor structure suitable for AC decomposition in heat pump conditions was finally obtained.

To study the start-up characteristics and temperature fluctuation of the loop heat pipe, this paper prepared a nickel wick using a sintering method. The start-up characteristics of the loop heat pipe system under different thermal loads were explored, and the effects of different thermal loads and filling rates on temperature fluctuations were analyzed. Meanwhile, the system variable load operation characteristics and the system thermal resistance changes under various thermal loads and filling rates were investigated. Results showed that the heat pipe could be started successfully under 5—25W heating power, and the higher the power, the faster the start-up; under low load, the evaporation efficiency of the heat pipe was far less than the condensation efficiency, and the evaporation efficiency and condensation efficiency were equal with the heating power around 20W; temperature fluctuations existed under smaller load and disappear after the heat load reaching 20W; significant temperature fluctuations of large filling rate under the same conditions were observed; thermal resistance decreased with the increase of thermal load, and the smaller the load, the greater the impact on the thermal resistance; under low load, the filling rate had a greater impact on the thermal resistance, and vice versa; under experimental conditions, the minimum thermal resistance and the optimal system heat transfer were obtained when the filling rate was 60%.

Medium-low temperature coal tar (LTCT) is a kind of heavy oil with high density and high viscosity. Hydrotreating is an important means for clean utilization of LTCT, which is mainly completed in trickle bed reactor (TBR). As an important component of TBR, the gas-liquid distributor affects the performance of catalyst bed in the reactor. In this paper, a computational fluid dynamics (CFD) model based on Euler-Euler method was established, and the model was verified according to the cold model experiment results reported in the literature. The flow of LTCT and hydrogen in four kinds of distributors (bubble cap, multiport chimney, slot chimney and vapor-lift tube) was simulated. The liquid distribution, flow behavior and pressure drop of the distributors were compared and analyzed. In addition, the concept of liquid maldistribution factor (M_f) was introduced to quantitatively evaluate the gas-liquid distribution effect of four kinds of distributors. The results showed that the liquid phase coverage of LTCT was the widest after passing through the bubble cap. When the bubble cap was at y=-200mm section, the M_f value was 0.13, the distribution effect was the best, and the gas-liquid two-phase flow concentration phenomenon was not serious.

To improve convergence performance of distillation column simulation, a constant heat transport model was improved and extended to complex columns. A new initialization method was proposed based on the improved model, which could estimate the temperature, flow rates, and composition profiles of a complex column using simple calculations. Two separation processes were used to evaluate the proposed initialization method. The results showed that the proposed method had a similar time consumption with the existing initialization methods, while the obtained initial distribution was closer to the final simulation result than the existing ones. For a nonideal distillation process which was difficult to be converged using other initialization methods, convergence could be obtained using the proposed one.

As an important part of microfluidic equipment, the micro mixer is widely used in the biochemical field. Because the fluid flow in the micro channel is laminar and the mixing is poor, the mixing becomes the main factor affecting the efficiency for rapid reaction. In this paper, three kinds of micro mixer structures that affect the mixing efficiency were numerically simulated. By changing the three structural parameters of the micro mixer, namely, the channel width to height ratio, the maximum width at the divergence, and the dislocation height at the collision, the mixing performance under laminar flow was simulated. The results showed that the height of dislocation at the fluid collision had the most obvious influence on the mixing performance. The structure of the micro mixer (MST) with the best simulation results was further optimized to obtain a new micro mixer (MTT). The MTT was compared with MST and ordinary T-type micro mixer (MT). The mixing index at the outlet of MTT micro mixer reached 81%, while that of ordinary T-type micro mixer was only 5.3% under the same conditions. Through simulation and analysis of the mixing process, the structure of the dislocation collision type micro mixer was effectively improved, which was conducive to improving the fluid mixing efficiency and the reaction speed.

Solvent deasphalting can broaden the limited range of raw material composition and properties to avoid the restriction of high carbon residue and high metal content. The flexible combination of solvent deasphalting and conversion process can deal with residual oil, oil slurry and oil sand asphalt with large molecular weight, low hydrogen content and high impurity content, significantly improve the conversion rate, reduce the severity of unit operation, and improve economic benefits. The characteristics of solvent deasphalting technology are analyzed, and the application and implementation effects of solvent deasphalting technology successfully industrialized at home and abroad are summarized. The latest progress of hydrogen conversion, cracking, gasification and other combined processes with solvent deasphalting technology as upstream or downstream process are reviewed. The solvent action and R&D progress are described based on the classification of low carbon hydrocarbons, CO₂ and its modifiers, and coprecipitators. The new technologies for tower and internal structure optimization and equipment transformation are analyzed. It is pointed out that more basic and optimization research on solvent deasphalting technology are needed in the future. It is proposed that the future development direction of solvent deasphalting technology may be to further improve extraction efficiency, reduce energy consumption, expand the application in unconventional crude oil upgrading, and directly or indirectly convert poor oil/oil sand/unconverted oil into high value-added chemicals.

The blockage caused by hydrate formation and deposit is always a troublesome problem threatening deepwater oil and gas flow assurance. One effective way to mitigate the hydrate risk is injecting hydrate anti-agglomerants (AAs), due to their capability of inhibiting hydrate particles aggregation in oil-water systems. Based on the work of our research group on hydrate inhibition technology, the structure-activity relationship of surfactant- and solid particle-based AAs was reviewed, respectively. At the same time, performance test methods at macro, micro and molecular scales were investigated, including high-pressure stirred reactor, rocking cell, flow wheel and flow loop, micromechanical force apparatus and molecular dynamics simulation. According to the above experimental setups and molecular simulation results, the action mechanism of different types of AAs on hydrates, especially emulsification and adsorption mechanism, was summarized. Finally, the existing drawbacks of hydrate inhibitors were analyzed, and the future development of the aspect was prospected. It will provide important guidance for the design of efficient, green and economical hydrate AAs suitable for deepwater oil and gas fields in the South China Sea in the future.

Fossil fuels meet most of the world’s energy demand today. But too much use of conventional fossil fuels is causing many severe problems, such as environmental pollution, global warming and energy crisis. Therefore, looking for environmentally friendly fuels is very necessary. Ammonia has attracted more and more attention because it is a carbon free carrier with advantages of high energy density and low cost. However, ammonia usually need to co-fire with some fuels such as coal, CH₄ and syngas to improve the combustion characteristics of pure ammonia. This article introduces a detailed development of ammonia/coal and ammonia/methane as fuels for main applications such as boiler and gas turbine. It summarizes the fundamental combustion characteristics and the application research progress of ammonia blends. What’s more, the current understanding of combustion characteristics and the emission characteristics are also summarized. However, using ammonia blends as alternative fuels still has many challenges. In future, the improvement of combustion strategies, equipment and injection strategies is very urgent in order to apply ammonia as a practical fuel with high efficiency and low emission.

The increase of reactor pressure drop is an important factor affecting the long-term operation of industrial residue hydrotreating unit. Three sets of industrial residue hydrotreating units processing different typical raw materials were selected to analyze the impurity deposition and pore structure changes at different locations of the catalysts after operation. The SEM-EDS Mapping method was used to in situ characterize the impurity deposition distribution of agglomerated catalysts, and the impurity deposition rules were obtained. The rise mechanism of reactor pressure drop was analyzed based on the properties of the raw materials and the operating conditions. The results showed that a large number of metal impurities and carbon deposits were deposited on the catalysts in the front of the reactor during the long period operation, and the pore structure of the catalysts changed significantly. At the same time, a large amount of coke or iron containing scale was deposited in the gap between catalyst particles, causing bed plugging. Ni and V were mainly deposited within the catalyst particles, while Fe and Ca were deposited between catalyst particles or attached to the external surface of the catalysts, and a large amount of coke was filled in the gap of caked catalyst particles. The increase of reactor pressure drop followed two different mechanisms. When the content of Fe and Ca in the raw materials was low, the demetallization catalyst at the lower part of the reactor would be deactivated due to the deposition of metal Ni and V, and thus formed a large amount of coke between catalyst particles, resulting in bed hardening and pressure drop increase. When the content of Fe and Ca in the raw materials was high, a large amount of Fe and Ca would deposit among the guard catalyst particles at the upper part of the bed, which led to reactor blockage and high pressure drop. Therefore, controlling the content of Fe and Ca in the feed should be strictly controlled, and the design and grading of the catalysts should also be optimized to extend the operating time.

Using CaSO₄ as the oxygen carrier, the CaSO₄-Ash composite oxygen carrier modified by Jiangjunmiao coal ash was prepared by mechanical mixing method. With the TG-MS device, the chemical looping gasification reaction characteristics of composite oxygen carrier CaSO₄-Ash and Jiangjunmiao coal were investigated, and the action mechanism of Jiangjunmiao coal ash-modified CaSO₄ oxygen carrier was studied. The results showed that Jiangjunmiao coal ash had a certain modification effect on CaSO₄ oxygen carrier. At 900℃, the CaSO₄-Ash composite oxygen carrier showed good reactivity and stability compared with the pure CaSO₄ oxygen carrier. The amount of CO produced by the chemical chain gasification of the CaSO₄-Ash composite oxygen carrier increased significantly, and the yield also more stable. X-ray diffraction (XRD) analysis showed that there were a small amount of Ca₂Fe₂O₅ and Fe₂O₃ in the CaSO₄-Ash composite oxygen carrier, which were attached to the surface of CaSO₄ and promoted the effect of CaSO₄ lattice oxygen migration as an intermediary for the transport of CaSO₄ lattice oxygen. The lattice constant and lattice volume of pure CaSO₄ oxygen carrier and modified CaSO₄ oxygen carrier were calculated by Jade software, and combined with Raman and Electron Paramagnetic Resonance (EPR) characterization, the mechanism for Na⁺ to modify CaSO₄ oxygen carrier in coal ash was proved. Through Scanning Electron Microscope (SEM) test, it was found that the surface pore structure of the modified CaSO₄ oxygen carrier was clearer.

Cu-SSZ-13 is an excellent deNO _x catalyst with CHA skeleton structure, and thus it possesses good application prospect in the field of vehicle exhaust deNO _x and has been applied commercially in Europe. However, the hydrothermal deactivation and sulfur poisoning of Cu-SSZ-13 will cause serious damage to the CHA skeleton structure and active sites of Cu-SSZ-13 and has limited its development. In order to solve these problems, the modification of Cu-SSZ-13 catalyst has become the focus of current research. The recent research progress on the active sites of Cu-SSZ-13 catalyst and the mechanism of its deactivation caused by hydrothermal aging and sulfur poisoning were summarized. Also, the latest modification methods aimed at improving the catalytic activity and tolerance of Cu-SSZ-13, such as creating new nanostructures, constructing poisoning sacrifice sites, metal doping modification, were discussed, which provides a new thought for enhancing the catalytic performance and anti-poisoning performance of Cu-SSZ-13. Furthermore, the future development of Cu-SSZ-13 modification technology was prospected with the innovative idea of regulation of the active site by specific metal doping and novel preparation methods to control the type of ions in the zeolite. Finally, the essential problems to be solved in catalyst modification were discussed.

Compared with brominated and iodinated substitutes, chlorinated substitutes are cheaper and more abundant in reserves. The downstream products such as aldehydes, carboxylic acids, amides and esters synthesized by carbonylation reaction have important applications in the production of bulk chemicals, fine chemicals and pharmaceutical intermediates. This paper comprehensively reviews the importance of chlorinated compounds carbonylation to synthesize high value-added chemicals, and introduces the research progress of several different types of chlorinated compounds (aryl chlorinated compounds, allyl chlorinated compounds, benzyl chlorinated compounds, α-chlorinated ketones, 1,1-dichloro-1-vinyl compounds, alkyl chlorides) and their carbonylation reactions (formylation, esterification, amination, carboxylation, etc.) in the development of new catalyst systems and efficient synthesis of target products. The difficulties and future development of carbonylation of such substrates are also prospected. In the future, the development of more types of reactions and catalyst systems that accomplish the mild carbonylation of chlorinated compounds would be a hot spot in organic chemistry research and industrial production.

Single-atom catalysts with unique physical and chemical properties are superior to traditional catalysts for some chemical reactions and thus will become the next generation catalysts. Single-atom catalysts technology has made great progress. Here, the origin of single-atom catalyst was traced back, and bibliometrics and patent statistics methods were used to analyze the related papers and patents in the field of single-atom catalysts from multi-dimensional indicators. The results show that both the basic theory and application research of single-atom are catalysts in the rising stage, and China is in the international leading position. In basic research, Chinese Academy of Sciences, Tsinghua University and the U.S. Department of Energy have demonstrated super strength. In application research, although China has the most patent applications, the patent layout in single-atom industrialization was best done by the U.S. governments. The most valuable patents for single-atom catalysts are those composed of active center of Pt atoms and carbon materials. Finally, the challenge to achieve real industrial applications of single-atom catalysis is pointed out to be the precise regulation of the catalytic materials within their single-atom limit.

In proton exchange membrane fuel cell (PEMFC), for the sake of cost and practicality, the oxygen required for oxygen reduction reaction is basically from air. However, the pollutants in the air, such as SO₂ and NO₂, will lead to the poisoning of Pt catalyst. Therefore, improving the anti-toxicity of the catalyst has become one of the key issues to promote the large-scale application of PEMFC. The research progresses in the development of anti-toxicity catalysts for oxygen reduction reaction (ORR) and the anti-toxicity mechanism were introduced in this paper. At present, many ORR catalysts has been developed, mainly including platinum-based catalysts, non-noble metal catalysts and carbon-based catalysts. Their anti-toxicity could be improved mainly by inhibiting the electronic interaction between poisonous substance and catalyst, enhancing the spillover effects, reducing the oxidation potential of poisonous substance, introducing heteroatom (such as nitrogen, phosphorus), etc. At the same time, it is faced with some problems, such as the decrease of catalyst conductivity and activity and the complex preparation procedure. How to develop a catalyst with good anti-toxicity while maintaining its activity and stability has become a key research direction.

To meet the requirements of sustainable development, photoelectric catalytic decomposition of hydrogen in the water, CO₂ reduction and degradation of pollutants, has become the research hot spot due to its predictability of advantage in energy storage and transport. Metal-organic frameworks (MOFs) material with high specific surface area, metal/organic ligand rich, large pore volume, structure and composition of the advantages of adjustable, has great potential in photoelectric catalysis applications. Therefore, this article mainly reviewed the research progress on the application of MOFs materials in the photoelectric catalysis from the three aspects of hydrogen production from water decomposition, CO₂ reduction and organic pollutants degradation. Firstly, the MOFs materials were introduced in the field of catalysis in recent years. Several widely used MOFs catalyst synthesis methods were summarized, and their advantages and disadvantages were compared. Secondly, a few basic mechanisms and the latest research progress in the application of MOF based photoelectric catalyst was introduced in detail respectively. Finally, the role of MOFs materials in optical electrode and the opportunities and challenges in the field of photoelectric catalysis was carried on the brief summary and outlook.

Phenol is an industrial chemical with a wide range of applications. Direct oxidation of benzene with molecular oxygen is a green route to synthesize phenol. A novel aldehyde-ketone resin-based nonmetallic catalyst was designed and prepared for direct oxygen oxidation of benzene to phenol. The morphology and structure of the catalysts were characterized by XRD, FTIR, SEM, XPS and N₂ adsorption-desorption. The results showed that the prepared nonmetallic catalysts were amorphous carbon materials with abundant functional hydroxyl and carbonyl groups which were affected by the ketone sources. In addition, the reaction conditions were optimized and a yield of phenol of 16.3% was achieved. The performance of the papered catalyst was comparable to that of metal catalysts. Besides, kinetic studies showed that the reaction was a first-order reaction and the rate constants for each reaction step were calculated. Combining characterization, kinetic experiments, and controlled experiments, we found that the abundant ketone groups on the catalyst surface were the active sites. Based on this, the reaction mechanism was proposed.

Adsorption coupled with catalytic oxidation is the most efficient, economical and environmentally friendly method to remove volatile organic compounds (VOCs) at present. Zeolite possesses large specific surface area, regular microporous channel and stable structure. Therefore, zeolite has important application value in the removal of industrial VOCs as adsorbent and catalyst. This paper summarizes the rules of VOCs adsorption by zeolites and the effects of microstructure and surface properties of zeolites on the catalytic oxidation of VOCs in recent years. The key factors affecting the adsorption of VOCs include the zeolite topology and its cation type, pore multipolarization, and hydrophobicity. Zeolite catalysts loaded with noble/non-noble metals are mainly discussed. The key points to obtain efficient catalysts are: effective controlling the particle size of metal species on the zeolite carrier of suitable structure and morphology, regulating the chemical state of active species and their interactions with zeolite carriers and understanding deeply the influence of zeolite microstructure, active species status and other factors on the catalytic performance.

Magnesium based hydrogen storage materials have the advantages of high hydrogen storage capacity, low price, and abundant magnesium resources in nature, and thus are considered as the most promising solid hydrogen storage materials. Due to the good stability of MgH₂, the high enthalpy of hydrogen desorption (75kJ/mol H₂), the high dissociation energy of hydrogen molecules on the surface of Mg and the slow diffusion rate of hydrogen atoms in the magnesium lattice, the absorption and desorption of hydrogen are stable in thermodynamics but the kinetics is slow, which limits its application in hydrogen storage. Many research achievements have been made to improve the properties of magnesium based hydrogen storage materials and this paper reviews these research reports, and summarizes the modification methods with the focuses on the effects of alloying, nanocrystallization and catalyst addition on the optimization and improvement of the thermodynamic and kinetic properties, and the mechanism of hydrogen absorption and desorption. Finally, the development prospects in this field are prospected. Based on the existing analysis, it is concluded that catalyst addition and nano modification should be comprehensively used to regulate the thermodynamic properties of MgH₂ system in the future research obtain the Mg/MgH₂ hydrogen storage system with high capacity and high performance, which could meet the requirements of commercial applications.

The low-cost production, safe storage and transportation, and efficient application of hydrogen are the focus of the current hydrogen energy researches. Among them, safe and efficient storage and transportation is the technical key to the large-scale application of hydrogen energy, so the research and development of high-capacity solid hydrogen storage materials have both academic significance and application value. Hydrogen storage by solid material has become the most promising hydrogen storage technology due to its large storage density and high safety factor, which has received widespread attention from researchers. In this paper, according to the current research status of solid hydrogen storage materials, the research progress of several solid hydrogen storage materials is discussed, including those based on physical adsorption, metal, coordinated hydride and hydrate. The most promising magnesium-based hydrogen storage materials are re-evaluated, and the effects of several modification methods such as alloying, nano-anodization, adding catalysts, and composite light metal coordination hydrides on the hydrogen storage mechanism, microstructure, thermodynamic properties and kinetic properties of magnesium-based hydrogen storage materials are elaborated. The integrated design considering production, storage and use of hydrogen should be the development trend for the industrialization of solid hydrogen storage.

Ionic polymer-metal composites (IPMC) are a kind of electroactive smart soft materials, which consist of an ion-exchange polymer film and two flexible electrodes on the upper and lower surfaces of the polymer film. Among them, the performance of flexible electrodes is important to the IPMC, which is one of the research hotspots in the field of smart soft materials. At present, there are relatively few works on the electrode of IPMC sensing, and the electrodes suitable for IPMC actuation generally meet the requirements of IPMC sensing. Thus, the recent progress of IPMC flexible electrodes from the aspects of material selection, fabrication and performance improvement for IPMC actuation was reviewed in this paper. Firstly, the composition, driving and sensing mechanism of IPMC were briefly summarized. Then, the electrode materials were classified, and the problems of different materials were summarized when used as IPMC electrodes, such as the fatigue cracking and low specific capacitance of metal electrodes, and the low conductivity of conductive polymer electrodes. Finally, the performance improvement of IPMC electrodes was mainly summarized and the development trend of IPMC flexible electrodes was prospected, which should have high conductivity, high specific capacitance and excellent stability for the application of IPMC intelligent devices.

A sonication-assisted liquid phase exfoliation method was demonstrated based on liquid cascade centrifugation and freeze-drying method, which was designed to prepare two-dimensional WS₂ nanosheet. X-ray diffraction (XRD), Raman, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and thermogravimetric and differential scanning calorimetry (TG-DSC) analyses were used to examine the morphology of two-dimensional WS₂ nanosheets and crystalline structures as well as their thermal stability. A four ball tribometer was used to characterize the extreme pressure, friction-reducing and anti-wear properties of lithium grease containing two-dimensional WS₂ nanosheets, and the wear scar of steel balls were observed under SEM. The results showed that the controllable and large-scale preparation of two-dimensional WS₂ nanosheet was achieved, and the prepared samples possessed consistent crystal form and lattice as well as good thermal stability. The tribological properties of all of the lithium grease containing two-dimensional WS₂ nanosheets were improved in comparison with lithium-based grease. Furthermore, 2.0% of WS₂-3 (as the optimal concentration) in comparison with lithium-based grease, improved the P_B and P_D values by 63.3% and 86.1%, and reduced friction coefficient and wear scar diameter by 19.3% and 34%, respectively.

Waste toner is ignored in current disposal of waste printers and toner cartridges, causing diffusion into the air and respiratory diseases. To use waste toner as light absorbing material for photothermal conversion, a two-step method was proposed to prepare waste toner-ethylene glycol phenyl ether nanofluids. The stability, optical properties and photothermal conversion properties were studied. The results indicated that the waste toner-ethylene glycol phenyl ether nanofluids had good stability without adding any surfactant, and the light absorption capacity of the base solution could be improved by adding waste toner particles due to the reduction of light transmittance and increase of extinction coefficient. In the photothermal conversion experiment, all concentration of the waste toner nanofluids showed good photothermal conversion effect. The optimal concentration in this experiment was 0.04% and the photothermal conversion efficiency was 54.95%, which was 90.41% higher than that of base solution. This study hoped to provide a new idea for photothermal conversion and reuse of waste toner.

Heterogeneous element doping is widely used in the modification of carbon quantum dots (CQDs) due to improving the fluorescence properties of CQDs. In this study, the nitrogen and sulfur co-doped carbon quantum dots (N,S-CQD) was prepared by electrochemical oxidation, in which Zhaotong lignite was selected as the carbon source, sodium chloride solution as the electrolyte and thiourea as the auxiliary respectively. The fluorescence quantum yield was 1.60%. The structure, composition and optical properties of N,S-CQD were studied by a variety of spectroscopic methods. N,S-CQDs were spherical particles with uniform size distribution and an average particle size of 1.66nm, in which C and O elements dominated as well as a certain amount of N and S elements. N,S-CQDs significantly absorbed in the UV region, and fluorescence analysis indicated that their optimum excitation wavelength and the emission wavelength located at 280nm and 313nm, respectively. N,S-CQDs were then applied to the detection of trace Fe³⁺ based on the quenching effect of Fe³⁺ on the fluorescence intensity. N,S-CQDs exhibited high selectivity and sensitivity for Fe³⁺ with the concentration range of 15—150μmol/L, and the minimum detection limit (L) was calculated to be 1.22μmol/L, indicating that N,S-CQDs could be utilized as a reliable candidate material for detecting trace Fe³⁺.

The cyclic oligomers were prepared by extraction method in melting polycondensation of polyethylene terephthalate (PET) and cyclodepolymerization method, respectively. The structure, component distribution and thermal properties of the cyclic oligomers obtained by the different preparation methods were systematically characterized. The results showed that both the extraction method in melt polycondensation and the cyclodepolymerization method with the aid of diphenyl ether and n-hexadecane were effective in the preparation of cyclic oligomers with the highest yield of 80% obtained by the diphenyl ether method and the lowest yield obtained by the extraction method. The cyclic oligomers products had the highest content of cyclic trimers and the cyclic oligomers prepared by the extraction and diphenyl ether method had a wide ring distribution, while the cyclic oligomers prepared by the n-hexadecane method had a narrow ring distribution. The oligomers prepared by the extraction and diphenyl ether methods indicated endothermic peaks around 190℃, 270℃ and 310℃, while the n-hexadecane method only showed endothermic peaks around 280℃ and 310℃, which corresponded to the melting points of the products. The cyclic oligomers prepared by the three methods all had good thermal stability.

As an important component of volatile organic compounds (VOCs), triethylamine (TEA) can cause serious harm to human body and the environment, and thus the detection of triethylamine is of great significance. In this paper, the semiconductor oxide Pt/ZnO heterostructures were designed and synthesized by hydrothermal method, and their gas sensitive properties were systematically studied. The crystal structure and microstructure of the sample, pore structure, element valence band structure and the molecular structure and surface structure were characterized by using X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and BET nitrogen adsorption, ultraviolet-visible spectra (UV-vis) and X-ray photoelectron spectroscopy (XPS), respectively. The results showed that the morphology existed in the form of irregular nanoparticles and the pore size distribution was mainly about 3.5nm, which belonged to the mesoporous structure. Gas sensing studies found that the optimal working temperature of Pt/ZnO nanoparticles continued to increase in the studied range, and thus the doping of Pt at the optimal working temperature of ZnO (180℃) was chosen to explore the effect of Pt on the gas-sensitive properties of ZnO. At the optimum operating temperature of ZnO, the sensitivity of Pt/ZnO sample with Pt content of 0.5% to 100μL/L TEA was improved by 66 times compared with ZnO at the optimal working temperature of ZnO, and the adsorption and desorption times were improved by 118s and 19s, respectively. The gas-sensitive mechanism study indicated that the generation of heterojunctions in the composite was an important reason for the improved gas-sensitive performance.

The application of phase change material (PCM) to building roofs in hot summer and cold winter areas can effectively reduce the temperature of the inner surface of the roof, and the phase change temperature of PCM affects the starting point of PCM heat absorption and release, so the selection of PCM phase change temperature is crucial. In order to find out the best phase change temperature for the phase change roof in hot summer and cold winter areas, this paper, with 4℃ as the temperature interval, respectively, filled decanoic acid (31℃), 70% lauric acid+30% nutmeg (35℃), 82% lauric acid+18% stearic acid (39℃), lauric acid (43℃) and hexadecanol (48℃) into aluminum foil bags for packaging, and then divided them into six small lattices of the same size with glass fiber insulation board. PCM roof and high reflectivity coating were combined to form a new type of high reflectivity PCM roof. The thermal protection performance of 6 kinds of roofs was continuously monitored for 3 days (August 16th—August 19th). The results showed that the roof insulation effect was the best when the phase change temperature was 35~39℃. The maximum temperature reduction rate (MTR), attenuation coefficient (DF) reduction rate and time delay coefficient (TL) of the phase change roof were 17.64℃, 16.4% and 167min, respectively.

Based on the molecular design, a novel fluorescent self-healing hydrogel (CSA Hydrogel) with low cost and multi-functional integration properties was synthesized by the modified chitosan and sodium alginate via Schiff base crosslinking. The result was found that the hydrogel had a rapid gelatinization ability and the shortest time was 3 minutes. The hydrogel also showed the excellent self-healing ability, concretely, the self-healing phenomenon could be realized with the shortest time of 2 hours at room temperature and the self-healing efficiency was high. It was worth noting that CSA hydrogels can stably release strong blue fluorescence under 365nm UV light, and show the wavelength dependence of fluorescence excitation. In addition, the sol-gel phase transition of hydrogels could be realized by adjusting the pH of hydrogels, and then the dynamic recombination of hydrogels could be achieved. The hydrogel materials with pH responsiveness, self-healing properties and fluorescence properties provided a new idea and an important guidance for the development of a new generation of smart materials, which could be used in the field of biological imaging and information security.

Novel tannin polypropoxy ether carboxylates (TEPEC) equipped with excellent plasticization and migration resistances for PVC resin were synthesized through the propoxylation of tannin extracts derived from waste bark and then esterification with fatty acid (acetic acid, butyric acid, and oleic acid). Then the structures of tannin-based polypropoxy polyol and its esters (TEPEA, TEPEB and TEPEO) were confirmed by GPC, ¹H NMR and FTIR. The performances including surface morphology, tensile property, low temperature resistance and volatility resistance, as well as migration resistances of PVC samples plasticized by tannin polypropoxy ether carboxylates (PVC/TEPEA, PVC/TEPEB and PVC/TEPEO) were systematically investigated and respectively compared with that of neat PVC and PVC blended with dioctyl phthalate (PVC/DOP). Additionally, low molecular weight tannin polypropoxy ether acetate (LTEPEA) was also synthesized and used as a reference to evaluate the effect of propoxy unit on the properties of PVC samples plasticized by tannin polypropoxy ether carboxylates. The results indicated that the overall performances of PVC samples plasticized by tannin polypropoxy ether carboxylates were dependent on their structures, where the performances of PVC plasticized by tannin polypropoxy ether carboxylates holding largest propoxy units and shortest methyl group (PVC/TEPEA) were better than PVC samples blended with others plasticizers (PVC/TEPEB, PVC/TEPEO and PVC/DOP). All of the results suggested that tannin polypropoxy ether acetate (TEPEA) had a great potential to totally the traditional petro-based DOP applied in PVC industry.

The unique advantages of nanoparticles and polymer stabilized foam make it a research hotspot to solve foam stability. In this paper, the effects of hydrophilic silica nanoparticles (NPs) and polymer xanthan gum (XG) on foaming properties, foam stability and spread ability of fluorine-free foam dispersion were explored. The results showed that NPs and XG significantly affected the stability of foam. Compared with NPs, the addition of XG helped to enhance foam stability, but inhibited the foaming performance of foam dispersion. When the mass fraction of NPS was 3.0%, the foaming ability of foam dispersion was improved. When NPs and XG were used together, the additive concentration was controlled, and there was a synergistic effect on the stability of foam. During the spreading process, the viscosity of foam dispersion increased after added NPs and XG that made the spreading speed of foam dispersion on the heptane surface slow down to varying degrees, but it had adversely effect on fire fighting.

Sulfur iron ore mediated autotrophic denitrification is an economic, efficient and green biological treatment technology with the advantages of saving external organic carbon sources, removing nitrogen and phosphorus simultaneously, and reducing sludge production and CO₂ emissions, which is the frontier and focus of wastewater treatment in recent years. This paper systematically summarizes the phenomenon of sulfur iron ore mediated field autotrophic denitrification in natural habitats, and the current status of sulfur iron ore supports biological treatment technologies; analyzes the effects of key factors such as their physicochemical properties, dosage, operation pH and temperature on systems’ performance; describes functional microorganisms of sulfur/iron oxidation coupled with nitrate reduction and their potential biochemical mechanisms; discusses the development difficulties such as bioavailability of sulfur iron ore and the inhibition of iron sediment. And finally the corresponding potential countermeasures are proposed. In summary, this paper outlined four aspects of the current status, influencing factors, biological mechanism, and development difficulties, which improves the understanding of sulfur iron ore mediated autotrophic denitrification and thus promotes its application in wastewater treatment.

Temperature phased anaerobic digestion (TPAD) consists of thermophilic pre-phase and mesophilic post-phase, which is a new type of anaerobic digestion process suitable for energy-based treatment of organic waste in recent years. It combines the advantages of mesophilic and thermophilic anaerobic digestion, and effectively improves the anaerobic digestion efficiency of organic wastes. Researches show that it has a broad application prospect and is a hot spot for anaerobic digestion of organic wastes in recent years. In this paper, the advantages of TPAD were analyzed by combing the literature in the past 20 years, and the operational effects and focused on the effects of factors including substrate, temperature of front and post phase, residence time, and pH of the front phase on TPAD were introduced. Moreover, this review summarized the microbial community structures and their interactions in detail. The assessments of TPAD were carried out. Finally, the potential problems that may be encountered in practical application were discussed and the prospective development of TPAD was proposed, in order to provide a systematic and scientific reference for the improvement and application of the process and to promote the energy recovery of organic wastes.

With the popularization of “ultra-low emission” standard in cement industry, the NO _x emission limit is gradually reduced to 100mg/m³ or even 50mg/m³. The carbonaceous denitration in cement kiln is carried out by controlling pulverized coal combustion to produce coke and CO as the NO _x reducing agent. It has the advantages of no additional denitration agents, no ammonia emission, good compatibility with the cement production processes and low cost of technical revamp and operation, providing the auxiliary processes for the cement industry to achieve the “ultra-low emission” standard. In this paper, the main implementations of carbonaceous substance denitration were introduced, including the low nitrogen oxide burning in rotary kiln, the staged combustion in decomposition furnace and the addition of reduction zone. Then, the characteristics and mechanism of NO _x reduction by coke and CO were discussed. The reduction effects of coke are related to its specific surface area and reactive sites. The CO reduction can occur without catalysis, but the efficiency could be ignored when CO concentration is less than 1%. Coke, CaO and coal ash act as catalysts to reduce the lower temperature window limit of NO reduction by CO from 900℃ to 600—800℃. Finally, the influence of CO on SNCR and its mechanism were summarized. It is considered that carbonaceous denitrification and amino denitrification could be coupling and work together. Further research on carbonaceous denitration in cement kilns could focus on the following aspects: evaluating the denitration characteristics under more comprehensive and systematic conditions, clarifying the denitration mechanism by combining experimental and theoretical investigation, and developing the combined technology of carbonaceous denitrification and amino denitrification.

The corrosion phenomenon in life brings many safety hazards and economic losses, and coatings are widely used because they are simple and effective. In recent years, fly ash has attracted a lot of attention as a filler material in anti-corrosion coatings due to its own structure and excellent physical and chemical properties. The addition of fly ash has replaced or partially replaced material substances in anti-corrosion coatings, greatly reducing the economic cost of raw materials and improving the utilization of solid waste resources. The author first combined the basic properties of fly ash and discussed the principles of its corrosion resistance in terms of the physical shielding effect, mechanical properties and electrochemical protection of the coating, and clarified the role played by fly ash in it. Starting from the base materials used in the preparation of the coatings, the present stage of fly ash anti-corrosion coatings was classified into three main types: fly ash epoxy resin anti-corrosion coatings, fly ash silicate anti-corrosion coatings and other types of fly ash anti-corrosion coatings. The existing research progress and the nature of the fly ash used for each type of coating were also summarized and outlined. However, research on fly ash for anti-corrosion coatings was still on a laboratory scale at this stage, making it difficult to achieve large-scale industrial applications and suffering from poor performance and durability due to cost and process. Therefore, the development of low-cost fly ash anti-corrosion coatings with self-healing, self-cleaning and anti-pollution properties was an urgent problem to be solved.

In this paper, a coupling system of high-power UV-LED heat dissipation and nano TiO₂ photocatalysis acid red 26 was designed. The sewage was circulated to cool UV-LED, which could improve the working efficiency of lamp beads and realize the photocatalytic degradation and decolorization of sewage. The combination of ultraviolet light source cooling and sewage circulation system was the innovation of this paper. The layout of UV LED lamp beads was simulated and optimized. With wastewater decolorization as the probe reaction, it was found that wastewater cooling could reduce the junction temperature of UV-LED by 41.2%, the average irradiance and wastewater decolorization efficiency were increased by 11.03% and 1.68 times, respectively. The results showed that the photocatalytic activity was inversely proportional to the pollutant concentration. It was proportional to the initial concentration of catalyst and tended to be stable after reaching 0.75g/L. Considering the influence of adsorption and oxidation groups on the degradation rate, the optimal pH value was 2. Compared with the traditional annular reactor, the apparent quantum yield (AQY) and decolorization efficiency of the coupling system were 2.3 times and 4.3 times, respectively, and the energy consumption was only 9.1%. The coupling system had potential application value in the field of UV-LED temperature control and wastewater treatment.

The column leaching experiment of stabilized fly ash was established by simulating acid rain with “sulfuric acid + nitric acid” extractant to study the influence of acid rain seepage path on the leaching behavior of heavy metals in fly ash under the condition of damaged fly ash ton bags in the landfill. The results showed that the six seepage paths all promoted the leaching of Pb, Zn, Cu, Cd, Cr and Ni in stabilized fly ash to varying degrees. Compared with the horizontal seepage path of “upper left inflow-lower right outflow”, the vertical seepage path of “upper inflow - lower outflow” was more likely to promote the leaching of heavy metals in fly ash due to the double influence of gravity potential energy and matrix potential. Under the mode of “dynamic scouring + static soaking + dynamic scouring”, the cumulative leaching amount of heavy metals was higher. Under the seepage path of “upper left inflow-upper right outflow”, the fluctuation of pH of leachate was the smallest, the cumulative leaching amount of heavy metals was the lowest, and the stability of heavy metals in fly ash matrix was the best. The research results could provide a scientific basis for the evaluation of the leaching behavior of heavy metals from stabilized fly ash in extreme acid rain environment and the environmental risk management and control when the fly ash ton bag in the actual landfill was damaged.

A large number of oil-based drilling cuttings, which may cause serious harm to the ecological environment and human health, were produced during the process of shale gas exploitation. In order to realize the resource utilization of oil-based drilling cuttings, the influence of pyrolysis final temperature on the distribution and characteristics of oil-based drilling cuttings products was studied. The results showed that oil and gas desorbed substantially between 50℃ and 250℃, and the carbonate decomposed substantially above 450℃ gradually, and the sulfur elements in the oil-based drilling cuttings escaped to gas phase above 450℃, mainly in the form of H₂S. At the thermal desorption temperature higher than 300℃, the oil content of the oil-based drilling cutting residuals decreased to below 0.3%. The thermal desorption recovery oil was mainly composed of white oil with a moderate boiling points range equivalent to diesel oil. The total gas yield increased with the increase of thermal desorption temperature. This study could provide basic data for the design of process and device of oil based drilling cuttings thermal desorption.

The denitration efficiency, influencing factors and reaction mechanism of selective non-catalytic reduction of NO _x with solid polymer denitration agent (PNCR) were explored in a fluidized bed reactor. The results showed that the denitration using solid denitration agent was mainly a non-catalytic reduction reaction. As temperature increased from 850℃ to 1150℃, the denitration efficiency increased with temperature, with the highest denitration efficiency of 97% at 950℃, and then the denitration efficiency decreased due to the high-temperature oxidation. The reaction did not need the oxygen and the denitration efficiency gradually decreased as the oxygen concentration increased. Steam addition could weaken the oxidation of denitration agent by O₂ and delay the high-temperature oxidation reaction. In the thermal decomposition of solid denitration agent, O element mainly escaped in the form of CO₂. And N and C elements were converted into active free radicals such as NH, CH₂ and CN. CH₂ and CN could react and thus consumed the strong oxidizing groups (e.g., O₂, O and OH) in the furnace, and inhibit the formation of NO, which might further accelerate the reduction reaction of NH and other free radicals with NO to achieve high denitration efficiency. The research results could provide theoretical support and technical reference for the applications of polymer denitration technology.

As a major pollutant during sludge pyrolysis, strict emission control of heavy metals is beneficial to ecological environment and human health. To investigate the effects of temperature (500—900℃) and polyvinyl chloride plastic (PVC) blending ratio (5% and 15%) on the migration and transformation behaviors of heavy metals (As, Cr, Cu, Mn, Ni, Pb and Zn), pyrolysis experiments were conducted in a horizontal fixed-bed reactor. It was found that increased temperature and added PVC were beneficial to reduce the residual rate of As, Pb and Zn in biochar, but had almost no effect on the removal of Cr, Cu, Mn and Ni. In addition, the speciation analysis of heavy metals showed that with the increase of pyrolysis temperature, the overall conversions of heavy metals in biochar to more stable forms were observed, except for As. Meanwhile, based on the results of ecological risk assessment of heavy metals in biochar, it was found that the presence of PVC in the feedstock increased the ecological risk of heavy metals in the obtained biochar when the pyrolysis temperature was 500℃ and 600℃. This paper provided a valuable reference for actual industrial thermal treatment of sludge regarding the control of heavy metals emissions.

Sludge and its stabilized products are rich in functional organic matter, which can directly participate in the complexation process of heavy metals. By defining the binding properties of its products and heavy metals, hyper-thermophilic composting (HTC), a more advantageous sludge stabilization technique, might better assess the value of its land use. Adsorption experiments were used to investigate the binding capacities of Pb²⁺ to humic acids (HAs) derived from raw sludge (RS), thermophilic composting (TC) and HTC. The findings demonstrated that with composting time, the maximum adsorption values (q_m) of HAs derived from HTC and TC to Pb²⁺ steadily increased. During composting, the HTC-derived HAs content also increased significantly in comparison to TC-derived HAs, peaking on the 21st day. The adsorption capacity (on a dry basis) of HTC-derived HAs to Pb²⁺ (21d, 29.6mg/g) was 70.7% higher than HTC-derived HAs (21d, 17.3mg/g), indicating that HTC products had more benefits in the remediation of soil heavy metal contamination. The ¹³C NMR data showed that the phenolic and aromatic carbons of HTC-derived HAs increased more during composting, and the aromatic carbons of HTC-derived HAs grew more rapidly than TC in the early stage of composting (0—21d). Infrared spectroscopy, two-dimensional correlation spectroscopy and moving window analysis all indicated that the polysaccharides in HTC-derived HAs would initially combine with Pb²⁺. For the binding of Pb²⁺ to HTC-derived HAs, phenolic hydroxyl and aromatic groups were more important among them. Based on the previous insights, it was evident that HTC’s higher degree of humification and the rise in phenolic hydroxyl and aromatic groups were the main contributors to its stronger ability to bind, and HTC was helpful for the land use of sludge.

In view of the current Fenton oxidation method to remove NO in coal-fired flue gas, a large amount of H₂O₂ ineffectively decomposes to generate oxygen, the DTPMPA (diethylenetriamine pentamethylphosphonic acid) /Fenton system was used to oxidize and remove NO. The results showed that when NO removal efficiency of the system was 95.1%, the proportion of H₂O₂ ineffective decomposition decreased to 15.5%. The increase of DTPMPA concentration inhibited H₂O₂ ineffective decomposition, and it promoted NO removal when the concentration was low but inhibited NO removal when the concentration was high. The increase of H₂O₂ and Fe²⁺ concentrations had a certain promoting effect on NO removal and H₂O₂ ineffective decomposition, but when the concentration of both was too high, it also had a certain inhibitory effect on NO removal. Lower reaction temperature had little effect on NO removal, but weakened H₂O₂ ineffective decomposition. SO₂ had little effect on NO removal and H₂O₂ ineffective decomposition. Electron spin resonance technology and quenching addition experiments showed that the addition of DTPMPA increased the content of ·OH radicals and ·O₂^- radicals in the Fenton system, ·O{}_{\mathrm{2}}^{-} radicals were the main active species for NO removal, and the main pathway of oxygen generation was ·O{}_{\mathrm{2}}^{-} + HO· \stackrel{}{\to } O₂ + HO^-. Ion chromatography of the reaction products showed that NO was oxidized to NO{}_{\mathrm{2}}^{-} and NO{}_{\mathrm{3}}^{-} during the reaction.

Straw pretreatment is used to improve component fractionation as well as enzymatic efficiency. In this study, we proposed a green, mild and recyclable pretreatment method of acidic molten salt hydrate for agricultural straw, which could achieve selective hemicellulose fractionation and target depolymerization of hemicellulose to xylose while maintaining a high retention of cellulose. The optimal pretreatment conditions were 97℃, 19.0min and 3.3% sulfuric acid concentration, under this condition the xylose yield was 90.85% and the cellulose retention was 85.87%. After enzymatic hydrolysis of the pretreated residue for 72h, the glucose enzymatic yield was up to 77.81%. In addition, the recycling of ZnCl₂ in this system was also studied. After five cycles of recycling, the pretreatment xylose yield reached 87.69% with maintaining a high recovery of ZnCl₂ solids (80%), which was indicative of a good pretreatment effect.

The composition of soluble organic compounds in coking wastewater is complex and difficult to be biodegraded. In order to reveal the composition of soluble organic compounds in the biological effluent of coking wastewater from the molecular level, dichloromethane was first used as the extractant to separate the biological effluent of coking wastewater from Hebei Qian’an Hong’ao Industry and Trade Coking Plant into organic phase and raffinate phase through liquid-liquid extraction. The organic phase was separated into four components. According to the different polarity of the four components, the saturated and aromatic components with weak polarity were analyzed by GC/MS, and the resin and asphaltene with strong polarity were analyzed by Fourier transform ion cyclotron resonance mass spectrometry combined with electric spray ionization source (ESI FT-ICR MS).The SPE eluate was obtained from the strongly polar raffinate by solid phase extraction and analyzed by ESI FT-ICR MS. The results showed that one hundred and twenty kinds of compounds were detected in the saturated fraction, and the insoluble organics in the coking wastewater after biological treatment were mainly n-alkanes and alkanes with higher molecular weight. Thirty-four compounds were detected in the aromatic fraction, mainly alcohols, esters and phenols with high content, of which phenols were mainly alkyl substitutes of phenol. The resin, asphaltene and SPE eluate detected five main types of alkaline and non alkaline organics, including N _x, N₁O _x, N₂O _x, O _{xand O x S1, respectively. The distribution of compound types in resins and asphaltenes was similar, and the compounds in asphaltenes were more abundant. The distribution of compound types in SPE eluates was quite different from those in resins and asphaltenes. According to the carbon number distribution and DBE value, the molecular structures of the main compounds were obtained, which provided a theoretical basis for the optimization and improvement of the coking wastewater advanced treatment process.}

The production of valeric acid from anaerobic fermentation is currently limited by its low yield, and few studies have been reported on its production from food waste. Hydrothermal pretreatment has attracted widespread attention because it can promote the dissolution and hydrolysis of substrates, does not require the use of chemical reagents, and is simple to operate. In this paper, we investigated the effect of different hydrothermal pretreatment temperatures on the production of valeric acid during food waste fermentation inoculated with distiller yeast (DY) and waste activated sludge (WAS), respectively. The results showed that the yield of valeric acid could reach 16.19g COD/L (DY) and 18.55g COD/L (WAS) under the optimal hydrothermal pretreatment conditions (180°C), which were 3.66 times and 0.74 times higher than those of the blank group, significantly improving the valeric acid production. The metabolic analysis revealed that the hydrothermal pretreatment could increase the production of propionic acid and thus provide sufficient substrate for the production of valeric acid. In addition, the hydrothermal pretreatment effectively regulated the alcohol to acid ratio of the anaerobic fermentation substrate, and weakened the conversion pathway of valeric acid to heptanoic acid, thus leading to the higher accumulation of valeric acid. Microbial community analysis revealed that hydrothermal pretreatment increased the relative abundance of functional valeric acid-producing bacteria including Megasphaera and Dialister. It should be noted that there was no enrichment of functional valeric acid-producing bacteria in the DY-B group, while the relative abundance of Megasphaera and Dialister could reach 13.77% and 2.26% after hydrothermal pretreatment (180℃). Moreover, the relative abundance of Megasphaera in the WAS group was 6.21% and increased to 9.35% after hydrothermal pretreatment (180℃).

Anaerobic ammonium oxidation (Anammox) has gained intensive attention in wastewater treatment. Fe²⁺ plays an important role in Anammox system. By continuously increasing the total nitrogen (TN) concentration in the influent, the effects of Fe²⁺ on the nitrogen removal performance and bacterial physiology of Anammox expanded granular sludge blanket reactor (EGSB) were studied. When the concentration of Fe²⁺ increased from 1.00mg/L to 7.50mg/L, the nitrogen removal efficiency and the ability to resist nitrogen load apparently increased. Meanwhile, the concentration of extracellular polymeric substances (EPS) and heme c also increased gradually, reaching the maximum value of 242mg/g VSS and 3.76μmol/mg pro, respectively. The bacterial activity obviously enhanced. When the concentration of Fe²⁺ increased to 10.0mg/L, the nitrogen removal performance of the reactor decreased, the concentration of EPS and heme c also declined, and the bacterial activity reduced. Therefore, addition of 7.50mg/L Fe²⁺ could maximize the nitrogen removal performance of the reactor, improve the bacterial activity, make the granule more compact, as well as promote Anammox sludge sedimentation and aggregation. This work helps the further exploration of the mechanism of Fe²⁺ addition on Anammox system, which is important to cultivate high-performance Anammox sludge and ensures the efficient and stable operation of EGSB reactor.

Emission and direct utilization of coal tar caused severe environmental pollution. Thus, developing a green synthesis method and application of high-valued materials is critical to the utilization of coal tar. Herein, we successfully fabricated porous carbon nanosphere as CO₂ adsorbent using resorcinol and medium- and low-temperature coal tar as carbon sources to polymerize with formaldehyde via the Stöber method. The samples were tested and analyzed by scanning electron microscopy, N₂ adsorption-desorption, Fourier transform infrared absorption spectroscopy, and X-ray diffraction. We investigated the effects of pre-polymerization temperature, hydrothermal temperature, and coal tar ratio on the pore structure and adsorption performance of CO₂. When the pre-polymerization and hydrothermal temperatures were 60℃ and 200℃, respectively, the product had the highest specific surface and CO₂ adsorption capacity. The specific surface area of the C₁-R₁-RT-200 adsorbent was 787m²/g with the CO₂ adsorption capacity of 4.64mmol/g. The product had better CO₂ adsorption capacity when the mass fraction of coal tar was 50%—76%, which was much higher than that synthesized using the pure resorcinol model compounds. The CO₂ adsorption isotherm of the prepared porous carbon nanospheres matched well with the Langmuir isotherm model, indicating that the CO₂ adsorption of the porous carbon nanospheres was a monolayer adsorption. Our work could contribute to developing the green synthesis method for coal tar-based CO₂ adsorbents.

To explore the optimal treatment process of plant nutrient solution and biochar obtained from tobacco stem treated with near-critical water (NCW), an orthogonal test design was used to investigate the effects of different factors (solid-liquid ratio, temperature, and reaction time) on the liquefaction rate, biochar yield, gasification rate and nutrient content in the liquid phase. The article analyzed the optimum process conditions of tobacco stems with near-critical water by using the combined analysis of extreme difference, variance analysis and affiliation function. The results showed that: ①The optimal treatment combination of NCW liquefaction tobacco stem was the material-liquid ratio 1∶14, 180℃ and 15min. The conditions with the highest biochar yield and the lowest gasification rate were the liquid ratio 1∶4, 180℃ and 15min. ②The optimal treatment conditions for the content of organic matter, total nitrogen, phosphorus, kalium, medium and trace elements in the liquid were 1∶4, 180℃ and 15min, respectively. ③Combined with the process optimization target and the quality of plant nutrient solution, T9 was the optimal treatment. Under this treatment, the liquefaction rate of tobacco stem was 51.8%, the biochar yield was 31.8%, and the comprehensive utilization rate was 83.6%. The organic matter content of the plant nutrient solution was (63.1±1.2)g/L, the total content of nitrogen, phosphorus and potassium (N + P₂O₅ + K₂O) was (5.748±0.017)g/L, and the content of medium trace element was (101.0±3.2)mg/L, which met the relevant enterprise standards and could be used as plant nutrient solution.