From the perspective of the hydrogen energy industry,the current situation of “production-storage-transportation-application” stages of hydrogen energy industrial chain is expounded.The technical status and challenges of hydrogen production via water electrolysis,hydrogen storage and transportation,and hydrogen energy terminal applications are analyzed.It is suggested to establish water electrolysis hydrogen production bases in Southwest,North,Northwest,and coastal regions of China,thereby forming a supply pattern of “hydrogen from West to East,North to South,and marine hydrogen for land use.” It advocates for a ‘two-step approach' to promote hydrogen energy vehicles and the construction of hydrogen refueling networks,build a hydrogen chemical industrial chain,drive the development of hydrogen metallurgy,and tackle the R&D of terminal facilities such as hydrogen fuel cells,kilns,and gas turbines.It also suggests to further improve the policy and institutional support system for the hydrogen energy industry,thus promoting the high-quality development of China's hydrogen energy industry.
This paper summarizes the key high energy consumption links,key material loss and production scheduling,traditional energy-saving and efficiency improvement measures as well as pollution control measures in the existing oil and gas production process.Based on system optimization thinking,major revolution modes are subversively proposed for the production process in oil and gas fields.The main paths and development directions for process re-engineering for the reduction of pollution and carbon dioxide emission in oil and gas production are subject to the high collaboration and efficiency enhancement among the material flow reconstruction based on “intensive transportation of oil and gas,and recycling of wastes”,the energy flow remodeling based on “clean energy substitution and utilization of residue energy”,and the information flow reconstruction based on “artificial intelligence”.
This review summarizes the latest research advances in cerium dioxide (CeO2),noble metal cerium-based catalysts,and composite transition metal oxide cerium-based catalysts for formaldehyde catalytic oxidation.It particularly focuses on elucidating the key factors governing the catalytic performance of cerium-based catalysts,including the structure and properties of catalyst supports,the types and structural characteristics of noble metals and transition metals,metal-support interactions,catalyst preparation methods,and reaction conditions.Combining with experimental characterization and theoretical calculation,the reaction mechanism of formaldehyde oxidation over cerium-based catalysts are elucidated,aiming to provide theoretical foundations and technical references for designing high-performance catalysts for formaldehyde oxidation.
The reaction mechanism of photocatalytic organic pollutants degradation is explored in this review.The modification strategy for photocatalytic materials and the influence factors for photocatalytic reaction process are summarized,and the impacts of energy band structure,crystal structure,operation conditions on the removal effect of pollutants are expounded.Meanwhile,the research direction in the field of photocatalysis is put forward.
Microplastics in constructed wetlands mainly come from anthropogenic sources (sewage discharge,agriculture and industrial production) and natural sources (surface runoff,atmospheric deposition).Main factors affecting the removal of microplastics include substrate interception,plant interception and absorption,biofilm retention,and microbial decomposition.It is shown by the analysis that the substrate plays a leading role in the removal of microplastics,the removal effect by plants is relatively limited,and microorganisms play a main role in decomposing microplastics.Studying the source and removal mechanism of microplastics in constructed wetlands is of great significance for improving the treatment efficiency of constructed wetlands and protecting the ecological environment.
Surface plasma resonance (SPR) spectroscopy technology is a highly sensitive surface analysis technology based on electron oscillations at the metal-dielectric interface,offering advantages such as real-time monitoring,label-free operation,and rapid response capabilities.The corresponding instrumentation has evolved into a multifunctional platform integrating excitation light sources,coupling prisms,detection chips,and microfluidic system together,and is widely applied in biosensing,environmental monitoring,and medical diagnostics.In recent years,the advancements have focused on enhancing sensitivity and expanding functional versatility.In the future,SPR technology will develop towards high integration,miniaturization,and multimodal technology convergence.Combined with artificial intelligence integration and standardization frameworks,SPR technology holds significant potential for broader societal and economic impacts in the fields such as materials engineering,precision medicine,and environmental health.
This review focuses on the global progress on research and application upon microbial remediation,phytoremediation,and microbial coupling with phytoremediation technologies,summarizes the existing problems,and prospects the research and application directions in the future,aiming at providing an important reference for high-quality development and green low-carbon application of coupled microbial-phytoremediation technique in petroleum-contaminated soil.
The article introduces the characteristics,applications,classification standards and grades of ultra-clean high-purity reagents.Combined with specific cases,it expounds systematically the latest research progress on various purification technologies,key equipment and materials,analysis detection methods and combined applications related to the preparation of ultra-clean high-purity reagents,in order to provide reference for the development of related industries in China.
This paper systematically elucidates the action mechanism by which microbial electrolysis cells (MECs) enhance the anaerobic digestion process through applying voltage to activate methanogenic communities and the electrodes promote direct electron transfer.It explores key technologies for optimizing MECs in enhancing anaerobic digestion,including the selection of optimal voltage,the minimization of electrode spacing,the design of single-chamber configurations,and the development of modified electrode materials.Additionally,it analyzes the positive role of MECs in enhancing anaerobic digestion stability,providing theoretical support and reference for their engineering application.
A detailed overview is provided,involving the structural features and electrochemical oxidation mechanism of boron-doped diamond (BDD) electrode,as well as its applications in treating with various organic pollutants.The challenges faced by BDD electrodes in practical application are analyzed,and their application prospects in environmental governance are discussed.Research directions in the future are also suggested,including further optimizing electrode performance and reducing cost,as well as exploring novel composite system to enhance treatment efficiency.
This review summarizes the research progress on cellulose aerogels in drug delivery system from the perspectives of synthesis strategies,drug loading methods,release mechanism and applications.Through integrating the existing research,it proposes the key issues of cellulose aerogels in drug delivery system and the development prospects in the future.
This review surveys the latest research situation on the utilization of coal gangue in China,with a specific emphasis on the high value-added utilization of coal gangue in modifying material,synthesizing geopolymer,zeolite and other porous silicate-based materials,as well as preparing ceramic materials.The mechanism involved in these utilization is elaborated.Through these utilization pathways,coal gangue is generally ground evenly and dried to enhance its reactivity.Subsequently,the resulting coal gangue powder or their mixture with other raw materials are treated with activators under hydrothermal or calcined conditions.These treatment leads to the decomposition of coal gangue into elemental monomers,such as silicon and aluminum.Ultimately,these monomers recrystallize to produce various high value-added materials at different temperature.Furthermore,this review suggests that the heavy metal elements released during the high value-added utilization of coal gangue can be recovered to reduce environmental pollution.
In order to avoid high energy consumption and high carbon dioxide emission in the thick oil thermal recovery process,the emulsified viscosity reducers for thick oil are reviewed,and the future development trend is discussed.The working principle,classification,advantages and disadvantages,and application scope of emulsified viscosity reducers are clarified,and the research progress on realizing green recycling of viscosity reducers are expounded,which provides guidance for the application of viscosity reducers in oilfields and the development of thick oil.
This work presents the main purification technologies for quartz,and briefly summarizes their benefits and drawbacks.It also describes the impurity elements in quartz and their endowment states,and analyzes the current research status of quartz purification technologies in the world.The content of SiO2 in quartz produced by deep purification technology is higher than that by other conventional purification technologies,making it more suitable for high-end industries.
This paper reviews the principles and research progress of current mainstream hydrogen storage technologies.By considering factors such as technology maturity,safety,hydrogen storage density,economy,and application scenarios,the characteristics of each technology is analyzed.Furthermore,the major challenges and opportunities faced during the development and commercialization of hydrogen storage technologies are expounded.Finally,the development trends of hydrogen storage technologies are proposed.It is indicated that although the existing storage technologies each have their advantages in terms of storage efficiency,safety,and economy,further research and optimization are still needed to meet practical application demand.In a long term,solid-state hydrogen storage technology demonstrates a promising application prospects.
This paper reviews the latest research progress on using microwave radiation to enhance the performance of CO2 absorbents,exploring its action mechanism,advantages,challenges,and future development directions,thereby providing theoretical foundations and practical guidance for the development of efficient and economical CO2 emission reduction technologies.
o-Methylacetanilide is prepared through acetylation reaction of o-toluidine.Then,MIL-101 (Cr) series MOF materials supported with tungsten-heteropolyacid are synthesized to catalyze the oxidation of o-methylacetanilide to o-acetyl aminobenzaldehyde.The catalysts are characterized by means of XRD,SEM,BET,TG and XPS.The influences of catalyst type,material feed ratio,reaction temperature and reaction solvent on the catalytic reaction are studied.Results show that the conversion rate of o-methylacetanilide can reach 73.3% when W2@MIL-101(Cr) is served as the catalyst,the molar ratio of o-methylacetanilide to hydrogen peroxide is 1∶4,reaction temperature is 75℃,and acetonitrile is served as solvent.The method is simple to operate and easy to purify the product,and total yield of the product can reach 66.1% under the optimal reaction conditions.
Using NFPP@C prepared by ball milling as the active material,conductive carbon black (Super P) as the conductive agent,and polyvinylidene fluoride (PVDF) as the binder,the cathode of zinc-ion batteries was fabricated,with a zinc sheet used as the anode.The effect of conductive agent content on the electrochemical performance of NFPP aqueous zinc-ion batteries was investigated.It is demonstrated that at a 0.2 C rate,the initial discharge specific capacities of the four kinds of cathodes prepared with different Super P contents are 104.3,94.6,86.4,and 60.1 mAh/g,respectively.After undergoing 100 cycles at a 0.2 C rate,their capacity retention rates are found to be 97.9%,84.5%,71.2% and 58.4%,respectively.The cathode with an NFPP∶Super P∶PVDF ratio of 8∶1∶1 exhibits the optimal electrochemical performance.
5-Hydroxymethylfurfural (5-HMF),a biomass-based platform chemical,is produced via one-pot production method through using xylose residue,a kind of industrial solid waste,as raw material in a water/tetrahydrofuran (THF) system.The catalytic activities of five sulfates including Al2(SO4)3,Fe2(SO4)3,ZnSO4,CuSO4 and Na2SO4 respectively combined with extremely low sulfuric acid are compared.The impacts of catalyst dosage,liquid-solid ratio,reaction temperature,reaction time,and the volume ratio of water to THF on the yield of 5-HMF are explored,and xylose residue before and after the reaction is characterized.It is indicated by the results that the extremely low sulfuric acid/Na2SO4 can be used as a suitable catalyst for the reaction.The yield of 5-HMF generated by hydrolysis and conversion of xylose residue is 50.65%,and the purity of the hydrolysate after simple purification reaches 80.34% when catalyst dosage is 5%,liquid-solid ratio is 15∶1,the volume ratio of water to THF is 1∶9,reaction temperature is 190oC and the reaction lasts for 90 min.
A series of xAl-KIT-6(SG) solid acid catalysts are synthesized by using a simple solid-phase grinding method with the three-dimensional ordered mesoporous KIT-6 as carrier,and applied to catalyze the decarboxylation of γ-valerolactone to butene.It is shown by the results that during the catalysts preparation process,a part of Al species exist in the form of aluminum-oxygen tetrahedron in KIT-6 skeleton,and the other part disperses highly on the surface of the catalysts in the form of Al2O3.The presence of Al species effectively creates large number of Brønsted and Lewis weak acid sites without destroying the three-dimensional ordered mesoporous structure of KIT-6.The decarboxylation of γ-valerolactone catalyzed by 4%Al-KIT-6(SG) catalyst can achieve a butene yield as high as 90.06% when the reaction temperature is 300℃,reaction time is 240 min and catalyst dosage is 10%.Meanwhile,after 6 cycles of regeneration experiments under the optimal catalytic conditions,the 4%Al-KIT-6(SG) catalyst shows excellent catalytic activity,achieving a butene yield of about 68%.
Z-type AgI/BiOI heterojunction photocatalysts are prepared via a simple ion exchange method,and their structure and morphology are characterized by means of XRD,SEM,TEM,UV-Vis DRS,and PL techniques.The photodegradation performance of the AgI/BiOI photocatalysts to oxytetracycline is examined under visible light.It is shown that after 150 min of visible light irradiation,the S2 photocatalyst (the molar percentage of AgI in AgI/BiOI is 50%) has the best degradation effect on oxytetracycline,delivering a removal efficiency of 76.1%,higher than that AgI or BiOI alone does.In addition,the removal efficiency of oxytetracycline by the S2 photocatalyst does not decrease significantly after five cycles of photocatalytic degradation,indicating a good cycling stability.The enhanced photocatalytic activity of AgI/BiOI composite is due to the formation of a Z-type heterojunction between AgI and BiOI,which enables charge carriers in the system to separate effectively.
Using cowbone powder as biomass raw material,MgCl2 and FeCl3 as modifiers,Mg-Fe oxides modified biochar (MFBC) is prepared via co-precipitation and co-pyrolysis methods,and applied to remove Pb2+ from aqueous solution efficiently.The prepared MFBC is characterized by using SEM,FT-IR,XRD and XPS,and the influences of different experimental factors on its performance in the adsorption of Pb2+ are analyzed through batch adsorption experiments.The adsorption characteristics of Pb2+ by MFBC is explored through adsorption kinetics model and isothermal adsorption model.It is found that the adsorption process fits well with the pseudo-second-order kinetic equation and Langmuir model,and is dominated by monolayer chemisorption.The adsorption mechanism of MFBC for Pb2+ mainly include surface complexation,cation-π bonding,ion exchange,and coprecipitation.In conclusion,MFBC prepared from waste bone resources is a promising and efficient adsorbent that can be used for the remediation of heavy metals contaminated water bodies.
Taking polyether sulfone (PES) tubular ultrafiltration membrane as base membrane,anhydrous piperazine (PIP) as water phase monomer,pyrobenzenetrisulfonyl chloride (TSC) and 1,3,6-naphthalenetrisulfonyl chloride (NTSC) as organic phase monomers,different types of polysulfonamide (PSA) tubular nanofiltration membrane are prepared through interfacial polymerization.The influences of the concentration of monomers and additives,the mixing proportions of TSC and NTSC,and reaction temperature on the performance of the prepared PSA nanofiltration membrane are studied.The physical and chemical structures of PSA tubular nanofiltration membrane are characterized by means of FT-IR and SEM,respectively.It is shown that polysulfonamide prepared owns the structural characteristics of two organic monomers by adjusting the proportion of monomers in organic phase and the reaction conditions,and exhibits better selectivity and rejection performance.
A novel iridium phosphorescent complex,Ir(piq)2(tffbd),is synthesized through using 1-phenylisoquinoline as the cyclic metal ligand and trifluoroacet-1-(2-furanyl)-1,3-butanedione as the auxiliary ligand.The chemical structure of the target product is confirmed by means of nuclear magnetic resonance spectroscopy and mass spectrometry characterization.The emission peaks of its fluorescence spectrum in ethanol solution are measured at 406 nm,429 nm,and 602 nm.The interaction between iridium complex and colloidal gold is tested.It is found through dynamic fluorescence effect that the fluorescence intensity of Ir(piq)2(tffbd) firstly increases and decreases then with the increasing amount of colloidal gold.It is shown by the first and second internal filtration fluorescence quenching detection that the fluorescence quenching degree boosts up with the increasing colloidal gold concentration.This study provides a data foundation for the application of iridium complexes in solution based fluorescence immunoassay and background fluorescence quenching detection.
Polyvinylidene fluoride (PVDF) blended hydroxymethylmelamine (MF) phosphate proton exchange membrane (PA/PVDF-MF-x) is prepared via steam induced film-forming method.The influence of MF doping ratio on the structure and properties of proton exchange membrane is studied.It is indicated by the experiment that the addition of MF improves the proton conductivity of PA/PVDF-MF-x membrane.PA/PVDF-MF-16 membrane suffers a mass loss of 14% at 200℃,presenting a good thermal stability.Its tensile strength at 25℃ is 8.1 MPa,its acid doping rate is 265%,and its proton conductivity is 42 mS/cm at 140℃ without additional humidity.The open circuit voltage of single cell installed with PA/PVDF-MF-16 membrane is 0.83 V,and the maximum power density reaches 265.2 mW/cm2,which exhibits good application prospect under high temperature and low humidity conditions.
Thiourea modified biochar (NS-800) is prepared from rice straw,and then loaded with iron-cobalt bimetallic materials to form CoFe@NS-800 composite.This composite is confirmed by various characterizations (SEM-Mapping,BET,XRD,FT-IR,XPS) to be rich in oxygen vacancies and reducing functional groups,which is conducive to the generation of Fe(Ⅱ)/Co(Ⅱ).In the degradation of ciprofloxacin by activated peroxymonosulfate (PMS),CoFe@NS-800/PMS system improves the degradation efficiency significantly compared with the material alone,demonstrating the ability of CoFe@NS-800 composite to activate PMS effectively.It is clarified by EPR and quenching experiments that 1O2 is the main active species.It is indicated by TOC and cycling experiments that the composite has high efficiency and recyclability,providing an economical and efficient catalyst for the treatment of organic pollutants in wastewater.
Fenton-like oxidation assisted ultrasound method is utilized to regenerate waste bio-based activated carbon,and the desulfurization effect of regenerated activated carbon is studied in detail.In the process of Fenton-like oxidation assisted ultrasound regeneration,the impacts of ultrasonic time,ultrasound power,pH value of Fenton-like reagent and H2O2 dosage on the regeneration rate of activated carbon are explored.The changes in specific surface area and surface chemical properties of activated carbon before and after regeneration are studied by means of BET and XRD.The study results show that Fenton-like oxidation assisted ultrasound regeneration can effectively improve the regeneration rate of waste activated carbon from 24.19% to 64.5%.The regenerated activated carbon presents the best desulfurization effect when the ultrasonic time is 50 min,ultrasound power is 80 W,pH is 5 and H2O2 dosage is 0.3 mL.After regeneration,the specific surface area of activated carbon increases from 318.48 m2/g to 326.37 m2/g,and the oxygen-containing functional groups on the surface increases,which improves the desulfurization rate of activated carbon.
TiO2 is prepared via the sol-gel method,and used as a carrier to prepare a series of supported nickel-based catalysts through the excess impregnation method.The conversion rate of m-chloronitrobenzene,the selectivity and yield of m-chloroaniline are taken as evaluation indicators to compare and analyze the performance of the catalysts prepared by different carriers.The physicochemical properties of each catalyst prepared are deeply analyzed by means of characterization methods such as N2 adsorption and desorption test,X-ray diffraction (XRD),and hydrogen temperature-programmed reduction (H2-TPR).Results show that the addition of TiO2 is conducive to the dispersion of metal Ni.Over the catalyst prepared by the optimal carrier,the conversion rate of m-chloronitrobenzene and the selectivity of m-chloroaniline are 100% and 98.69%,respectively.
In this study,the 0D/2D heterojunction (CoP/TiO2) is constructed through loading MOF-derived CoP quantum dots onto ultrathin TiO2 nanosheets,and applied for photocatalytic water splitting to hydrogen production reaction.The high specific surface area characteristics of ultrathin TiO2 two-dimensional structure provides an ideal substrate for the loading of CoP quantum dots,facilitating its uniform dispersion to construct interfacial sites.The unique structure of 0D/2D heterojunction is beneficial for the construction of abundant active sites at the interfaces,and also enhances effectively the charge transfer efficiency,thus improving the hydrogen evolution efficiency.The 5%-CoP/TiO2 catalyst with a CoP content of 5% delivers the highest hydrogen production rate of 2 375.30 μmol/(g·h), which is approximately 23 times and 170 times,respectively that pure TiO2 and pure CoP alone does.Photophysical and electrochemical analysis reveals that the 0D/2D heterojunction exhibits enhanced visible-light absorption and superior charge-carrier transport efficiency.Furthermore,based on the band structure analysis,it is indicated that the charge transfer type of this heterojunction is S-scheme,thus providing insights into the catalytic reaction mechanism.
Fe-based nanoparticles catalysts with different morphology are successfully prepared via electrochemical cyclic voltammetry and potentiostatic deposition methods.The early growth process and mechanism of surface electrodeposition of Fe-based nanoparticles are thoroughly investigated.The structure and properties of the catalysts are characterized by means of techniques such as scanning electron microscopy and electrochemical impedance spectroscopy.Fe nanoparticles prepared via the potentiostatic deposition method distribute uniformly and have a cubic structure.The active surface area of the glassy carbon electrode modified with these nanoparticles reaches 1.485 cm2,which is 22 times that of the bare glassy carbon electrode.Electrochemical catalytic performance experiments on catechol and hydroquinone show that the oxidation peak current of catechol and hydroquinone for the electrode modified with Fe nanoparticles prepared by the potentiostatic deposition method is significantly higher than that of the electrode modified with Fe nanoparticles prepared by electrochemical cyclic voltammetry method.Moreover,the oxidation potential of catechol and hydroquinone by the electrode modified with Fe nanoparticles prepared by the potentiostatic deposition method is lower.
Carbon nanotubes (CNTs) purified are immersed in aniline solution to prepare PANI/CNTs successfully via in-situ polymerization method.Pd is deposited onto PANI/CNTs composite carrier through electrodeposition method to obtain Pa modified PANI/CNTs composite catalysts.The physicochemical properties of the catalysts are characterized by means of TEM,XRD,cyclic voltammetry (CV),LSV,EIS,etc.The results show that compared with Pd/CNTs catalysts,polyaniline doping can improve the composite catalysts' conductivity and catalytic activity in hydrogen evolution,providing a conductive channel for electron or charge transfer and increasing the density of AC current.Pd-PANI/CNTs catalysts are expected to become a new type of hydrogen evolution support material.
A kind of magnetic covalent organic framework materials (Fe3O4@COFs) is synthesized via in-situ growth method,and applied to the adsorption of malachite green dye in water.The morphology of the prepared materials is characterized by means of transmission electron microscope,Fourier infrared spectrometer and XRD.The impacts of pollutant concentration,time,temperature and other factors on the adsorption performance of Fe3O4@COFs are explored with malachite green dye as model compound.It is found that the adsorption of malachite green dye by Fe3O4@COFs accords with the second-order adsorption kinetic model and Langmiur adsorption isothermal model.The adsorption equilibrium time is 20 min,and the maximum adsorption capacity is 328.4 mg/g.There exist hydrogen bonds and π-π stacking interactions between Fe3O4@COFs and malachite green dye molecules,which makes the materials exhibit excellent adsorption properties for MG.
TiO2 is added into a 1 mol/L LiPF6-EC∶DMC (3∶7) electrolyte,with a TiO2 mass fraction of 0%,5%,10%,and 15%,respectively to develop high-safety,high-voltage semi-solid electrolyte.It is revealed through electrochemical testing that the electrolyte containing 5% of TiO2 exhibits inferior performance compared to the baseline electrolyte,with a notable decline in discharge-specific capacity.In contrast,the LiNi0.5Mn1.5O4/Li battery using the electrolyte with 10% TiO2 demonstrates the best cycling performance,achieving a capacity retention of 98.4% after 400 cycles at 1 C rate.During rate capability tests,the battery with 10% TiO2 semi-solid electrolyte exhibits performance comparable to that of the battery with baseline electrolyte.This is because the ionic conductivity of the electrolyte with 10% TiO2 added decreases slightly,but its ion transfer number increases significantly.
A novel reactive template method is developed and employed in the synthesis of ZnS/ZnO composite structure in this study.The process involves the use of inexpensive magnesium oxide as a precursor,which undergoes a hydration reaction and cation exchange to produce Zn(OH)2.Subsequently,composite structure with varying ZnO to ZnS ratios is prepared through anion exchange.The resulting composite structure is in the form of nanosheets,exhibiting uniform distribution of elements and displaying exceptional photocatalytic activity in CO2 reduction.The optimal ZnS/ZnO ratio is determined to be 2∶1,leading to the production of CH4 and CO as reduction products.Furthermore,as a supercapacitor electrode,ZnS/ZnO composite structure after vulcanization has a specific capacitance of 342 F/g,and an energy density of 37.8 Wh/kg.Notably,this synthesis method is straightforward,environmentally friendly,and does not require additional heat or alkali sources.Moreover,it holds potential for extension to the fabrication of various other metal oxide or sulfide nano-structure.
Taking tetrapropylammonium hydroxide (TPAOH) as the sole template agent,silica sol and aluminum sulfate as silicon source and aluminum source,respectively,without seeds or additives,ZSM-5 zeolite aggregates self-assembled from 50-100 nm nanoparticles are synthesized via a one-pot hydrothermal synthesis method.The impacts of SiO2/Al2O3 ratio,Na+ concentration,and TPAOH dosage on the morphology of the zeolite are studied,and it is revealed that the nano-crystalline aggregate can be synthesized within a broad SiO2/Al2O3 ratio range [n(SiO2)/n(Al2O3)=40-200],and the primary particle size increases with a higher SiO2/Al2O3 ratio.Na+ concentration is a key factor governing the primary particles in the aggregate,its increase leads to larger primary particles.The higher TPAOH dosage results in larger primary particles but smaller secondary particles of the aggregate.Furthermore,a possible self-assembly mechanism is proposed based on monitoring the formation process.
The nitration reaction of toluene is carried out in a microchannel reactor with a volume of 10 mL through using sulfuric acid and nitric acid mixture as the nitration agent,and the impacts of resident time,reaction temperature,and sulfuric acid dehydration value on conversion rate and selectivity are explored.The sulfuric acid dehydration value required for the complete conversion of different aromatics are investigated,and the feasibility of sulfuric acid recycling is examined.The influence of the aromatics nucleophilic index on the dehydration value of sulfuric acid is determined through calculating.It is indicated by gas chromatographic analysis of the reaction products that compared with common reactors,the microchannel reactor has the advantages of faster reaction,controllable temperature,and improved product selectivity.
Poly(melamine-hexamethylene diisocyanate) resin (PMH),which containing chain amino groups,is synthesized through polymerizing melamine and hexamethylene diisocyanate.PMH is characterized by means of infrared spectroscopy,elemental analysis,thermogravimetric analysis (TGA),and temperature-programmed mass spectrometry (TP-MS),and its denitration performance is evaluated.Results show that the longer the polymerization time,the closer the nitrogen content in PMH is to that in the branched product,the higher the content of chain amino groups,and the higher the apparent activation energy of thermal decomposition.Thermal decomposition experiments show that PMH initially releases —(CH2)6NCO,and then the amide bonds on the chain undergo further cleavage,releasing ammonia and other small molecular products.As the polymerization time extends,the speeds of decomposition and release decline gradually.The denitration performance of PMH follows the following order:PMH(8 h)>PMH(6 h)>PMH(4 h).PMH's denitration activity corresponds to its thermal stability.
Acrylamide (AM) and ammonium persulfate (APS) are used as monomer and initiator,respectively to synthesize polyacrylamide (PAM) through free radical polymerization,which is then combined with hydroxypropyl trimethyl ammonium chloride chitosan (HACC) to form a HACC/PAM composite hydrogel.The prepared HACC/PAM hydrogel is characterized by means of SEM-EDS,FT-IR,XPS,and Zeta potential analysis.Its swelling behavior and reusability are also evaluated.Furthermore,the influences of initial concentration,adsorption time,pH,and temperature on the hydrogel's adsorption capacity for Congo red dye are studied.It is shown that the adsorption of Congo red by HACC/PAM hydrogel reaches the equilibrium,with a capacity of 183.22 mg/g when pH is 7,temperature is 25℃,the initial concentration of Congo red is 250 mg/L and the adsorption time is 60 min.It is revealed through adsorption isotherm and kinetic model fitting that the hydrogel's adsorption for Congo red follows the Langmuir isotherm model and pseudo-second-order kinetics,with a theoretical maximum adsorption capacity of 214.71 mg/g.Based on characterization and adsorption behavior analysis,the adsorption of Congo red by the HACC/PAM hydrogel is identified as a monolayer chemisorption process,jointly influenced by hydrogen bond formation,electrostatic interaction,and intra-particle diffusion.
A series of Ni-ZrO2 catalysts are synthesized via co-precipitation method at different calcination temperature,and applied for the selective hydrogenation of 2,2,6,6-tetramethyl-4-piperidone to 2,2,6,6-tetramethyl-4-piperidol.In order to figure out the effect of calcination temperature on the performance of the catalysts,the catalyst samples are characterized by means of XRD,N2 low-temperature adsorption-desorption,H2-TPR,H2 chemisorption and XPS.Results show that the optimized calcination temperature is 450℃,at which the catalyst prepared has an excellent activity and selectivity,with a large specific surface area as well as the active and reducible nickel species.The high selectivity of piperidinol is attributed to the active centers composed of electron-rich Ni and the reduced ZrOx together.After optimizing the reaction temperature,the conversion rate of 2,2,6,6-tetramethyl-4-piperidone reaches 99.9% and the selectivity of 2,2,6,6-tetramethyl-4-piperidol reaches 98.9% when the reaction over the catalyst performs at 105℃,0.8 MPa pressure,a liquid space-time velocity of 2.0 h-1,and a hydrogen-oil ratio of 12.Besides,the as-synthesized catalyst maintains excellent activity in a 500 h long-term evaluation process.
In this study,the chelating agent-entrapping agent system are employed to synergize with the supercritical CO2 extraction technique for the extraction and back-extraction of cobalt.Multi-factor extraction experiments are carried out to evaluate the impact of temperature,pressure and extraction time on the extractive efficiency of cobalt salts.It is determined that the optimal temperature,pressure,and extraction time are 60℃,14 MPa and 30 min,respectively.In this case,the highest single-stage extraction efficiency exceeds 95%.Moreover,the target metal cobalt is effectively recovered by the back-extraction experiment with a back-extraction rate of 91%.This study provides a certain reference for the recovery of high value-added metals from secondary resources.
Based on a 360 000 t/a green methanol process model,the energy consumption,economy and carbon dioxide emission of coal to methanol (CTM),biomass to green methanol (BTM) and CO2 direct hydrogenation to green methanol (CHTM) processes are analyzed.It is found that the unit energy consumption of BTM is 10% and 14.8% less than those of CTM and CHTM,respectively,and the unit cost of BTM is 26.9% less than that of CHTM.Both BTM and CHTM show near-zero carbon dioxide emission,with their full life-cycle carbon dioxide emission are 0.142 tons and 0.167 tons per ton of methanol,respectively,much lower than the 3.84 tons of CTM.
Aspen Plus software is employed to establish a plant-scale full process simulation for a 300 MW sub-critical unit,and three kinds of desulfurization wastewater zero discharge technologies with different heat sources are proposed,including high temperature bypass flue gas+drying tower crystallization technology,low-temperature flue gas driven triple-effect evaporation technology and low pressure steam driven triple-effect evaporation technology.Results show that the per unit heat consumption of two triple-effect evaporation technologies is lower,which is 0.017 kJ/t,less than 1/2 of the high temperature bypass flue gas+drying tower crystallization technology.Among them,the low-temperature flue gas driven triple-effect evaporation technology utilizes residual heat from flue gas,which has no impact on power generation and less impact on main generator,and obtains the highest boiler efficiency and unit efficiency,respectively 85.59% and 32.25%,so it has greater advantages in reducing energy cost and environmental pollution.The relevant research can provide reference for zero discharge of desulfurization wastewater from coal-fired plants.
In this study,a systematic process optimization is carried out for the synthesis of trichlorosilicon (TCS) from dichlorodihydrosilicon (DCS) and silicon tetrachloride (STC) through the anti-disproportionation reactive distillation process.Firstly,a suitable catalyst is identified according to the reaction characteristics,and the impacts of hydrogen chloride gas,nitrogen content in catalyst,reaction temperature,and reaction time on the catalyst activity are explored.To enhance the catalyst's activity and meet strict water control requirement,a catalyst pretreatment method is proposed to improve the catalytic performance effectively,which includes high-purity water washing to remove impurities,methanol dehydration,nitrogen purging and hydrogen chloride purging.Subsequently,a new type of catalyst bundling package is adopted for loading catalyst,reducing catalyst wear and offering advantages such as long catalyst lifespan,stable operation,and high operating flexibility.Finally,industrial experimental device design is conducted based on theoretical analysis,and control strategies are determined for the pre-separation column and the reactive distillation column.After the optimization,the reactive distillation column's operation conditions are set as follows:an operation pressure of adiabatic 150 kPa,a return flow rate 3-4 t/h,and a column top extraction temperature of 50℃.Under these conditions,the conversion rate of DCS increases to over 98.5%.This process has been applied in a certain industrial plant in China,which verifies its feasibility.
This study focuses on a triethylene glycol (TEG) dehydration system at a certain desulfurization station with a daily processing capacity of 2.2 million cubic meters.A thermodynamic coupling model is established,which integrating temperature,flow rate,and pressure factors.A synergistic optimization pathway is proposed based on water dew point constraint.Sensitivity analysis reveals the energy consumption correlation mechanism among high-pressure steam (52%),fuel gas (31%),and circulation pump electricity (17%),leading to the establishment of a multi-objective optimization function.Experimental results demonstrate that through reducing TEG circulation rate from 2 200 kg/h to 2 000 kg/h,optimizing the stripping gas flow rate from 21 Nm3/h to 7 Nm3/h,and adjusting the reboiler temperature gradient to 183℃,the system’s specific energy consumption decreases by 17.8% (6.48×10-4 kWh/m3),achieving annual operating cost saving of RMB 225 100 while maintaining water dew point stability below -20℃.This study provides a universal methodology for enhancing the energy efficiency of existing natural gas dehydration plants,advancing the transformation of energy-intensive industries from “single-factor energy conservation” to “systematic efficiency enhancement”.
The C3 splitter (propylene distillation column) in a certain new propane dehydrogenation (PDH) plant,which is designed with multi-pass trays,suffers from poor separation efficiency and low capacity utilization.These issues results in that the product purity does not meet specifications and unexpected product loss is encountered.This paper delves into the key parameters influencing the efficiency and capacity of multi-pass trays through the successful retrofit of this C3 splitter.In addition,by comparing operational performance of the splitter before and after the retrofit,the key design factors leading to the off-specification product are described.
GC/RGO-RuO2-PFDTES/$\mathrm{NO}_{3}^{-}$-ISE,a superhydrophobic all-solid-state selective electrode for nitrate ion,is constructed through using the prepared reduced graphene oxide-ruthenium dioxide (RGO-RuO2) composite as the solid-state contact layer,which is hydrophobically modified.It is indicated through SEM and XPS characterization on RGO-RuO2 that the successful composition between RGO and RuO2 can reduce the agglomeration tendency when they exist separately.The findings from detection and tests for the electrode that the electrode exhibits a good near-Nernstian response in the nitrate ion concentration range of 1×10-1 to 1×10-5 mol/L,with a response slope of -56.91±1.07 mV/decade and a detection limit of 3.46±1.18 μmol/L.The electrode presents excellent selectivity,good stability,strong pH applicability and superior resistance to water layer interference.The electrode delivers 97.18%-103.28% of spiked recovery rates for three actual water samples,and has a lifespan of 90 days,indicating a promising application potential in nitrate detection in actual lake water.
In this study,a dispersive solid phase extraction coupled with ultra high performance liquid chromatography-tandem mass spectrometry method is established through using UiO-67/GO,which is synthesized from metal-organic framework material and graphene oxide,as the adsorbent for the determination of 7 kinds of sulfonamides residues in biogas slurry.The slurry samples are extracted by Na2EDTA-McIlvaine buffer solution with a pH of 6,and UiO-67/GO is used as an adsorbent to adsorb the target substance.The target substance is purged with 5% ammonia-methanol,and quantitatively analyzed in MRM mode by ultra high performance liquid chromatography-tandem mass spectrometry.Results show that within the concentration range of 0.1-500 μg/L,these seven kinds of sulfonamides show good linear relationship,with R2 above 0.99,the spike recoveries between 71.2% and 92.9%,the relative standard deviation (RSD) of 4.2%-9.0%,the limits of detection between 0.1 μg/L and 0.4 μg/L,and the limits of quantification between 0.3 μg/L and 1.2 μg/L.It is verified that this method is suitable for detecting sulfonamides residues in biogas slurry in breeding farms.
