In this study, Fe3O4nanoparticles（Fe3O4NPs） were successfully prepared via oxidation–precipitation method and characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and Fourier transform inf...In this study, Fe3O4nanoparticles（Fe3O4NPs） were successfully prepared via oxidation–precipitation method and characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FT-IR）. The characterization results indicated that Fe3O4 NPs with regular crystal structure and a narrow of diameters had been synthesized successfully and had high purity. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous Fe3O4 catalysts in the presence of H2O2. The response surface methodology（RSM） based on Box–Behnken design（BBD） was employed to design and optimize individual and interactive effects of the four main independent parameters（catalyst loading, initial p H, reaction temperature and H2O2concentration） on decolorization efficiency of Orange II. A significant quadratic model（p-value 〈0.0001, R2= 0.9369） was derived using analysis of variance（ANOVA）. Optimum conditions were catalyst loading of 1.5 g/L, initial p H of 2.7, reaction temperature of 42 8C and H2O2 concentration of 22 mmol/L, respectively. The predicted decolorization rate under the optimum conditions as determined by the proposed model was 99.55%. Confirmatory tests were carried out and the decolorization rate of 99.49% was observed under the optimum conditions, which agreed well with the model prediction.展开更多
Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a...Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a novel pyrazine-based Fe-MOFs(MIL-101(Fe)-Pz)by substituting the 1,4-dicarboxybenzene acid ligands in typical MIL-101(Fe)with 2,5-pyrazinedicarboxylic acid(PzDC),in which sodium acetate was used as coordinative modulator to control the crystal size(2–3μm).The incorporation of Fe-pyridine N coordination structures originated from PzDC ligands gave MIL-101(Fe)-Pz narrowed band gap(1.45 eV)than MIL-101(Fe)(2.54 eV)resulting in improved visible-light adsorption capacity(λ>420 nm),and also increased the proportion of Fe(Ⅱ)in the Fe-clusters.Thus MIL-101(Fe)-Pz exhibited a synergistic enhanced photo-Fenton-like catalytic performance under visible-light irradiation.The MIL-101(Fe)-Pz/H_(2)O_(2)/Vis system could degrade 99%of sulfamethoxazolewithin 30min,whichwas 10-fold faster than that of the pristine MIL-101(Fe),it also effectively removed other organic micropollutants with high durability and stability.Mechanistic analysis revealed that the PzDC ligands substitution decreased the band gap of MIL-101(Fe),giving MIL-101(Fe)-Pz appropriate band structure(-0.40∼1.05 V vs.NHE)which can cover several light-driven process for the generation of reactive oxygen species,including Fe(Ⅲ)reduction and H_(2)O_(2) activation for accelerating•OH generation,as well as oxygen reduction reaction for generating H_(2)O_(2),O_(2)^(•−) and ^(1)O_(2).This study highlights the role of pyridine-N containing ligands in regulating the band structure of Fe-MOFs,providing valuable guidance for the design of Fe-MOFs photocatalysts.展开更多
Coupling adsorption and in-situ Fenton-like oxidation process was developed for Methylene blue(MB) using refined iron-containing lowgrade attapulgite(ATP) clay, and the removal mechanism was investigated. The MB was i...Coupling adsorption and in-situ Fenton-like oxidation process was developed for Methylene blue(MB) using refined iron-containing lowgrade attapulgite(ATP) clay, and the removal mechanism was investigated. The MB was initially adsorbed on the porous ATPs, and then the enriched MB was removed by the H2O2-assisted Fenton-like oxidation with the iron-containing ATP catalyst. Under optimal conditions, the ATP powder exhibits the maximum removal efficiency of 100% with negligible iron leaching(1.5 mg L^(-1)) and no sludge formation. Furthermore,polysulfone/ATP(PSF/ATP) pellets were fabricated through a water-induced phase separation process to construct a fixed-bed reactor(FBR) for continuous contaminant removal. For the first cycle, the maximum adsorption capacity was 15.5 L with an outlet MB concentration of1.973 mg L-1(< 2 mg L^(-1), GB4287-2012) using the PSF/ATP pellets containing 50.0 g of ATP powders, and the maximum Fenton-like oxidation capacity was 35.5 L with the outlet concentration of 0.831 mg L^(-1). After five cycles, the total treated volume of the MB solution was ca. 255 L, and the efficiency remained above 99%. After 10 h of continuous treatment towards practical resin industrial wastewater, the chemical oxygen demand(COD) removal efficiency was still measured at 83.05%, costing 0.398 $ m^(-3). These results demonstrate the practical applicability of iron-containing low-grade ATP clay for textile water treatment.展开更多
In this study,different types of small molecular carbon sources such as melamine,dicyandiamine,pyrocatechol,and o-phenylenediamine were used to regulate the surface structures of iron/nitrogen/carbonbased composites(F...In this study,different types of small molecular carbon sources such as melamine,dicyandiamine,pyrocatechol,and o-phenylenediamine were used to regulate the surface structures of iron/nitrogen/carbonbased composites(Fe-N/C),which were used to activate peroxymonosulfate(PMS).The relationship between different small molecular carbon sources and the electronic structure was investigated.The characteristics of metal-carrier interaction in the Fe-N/C were clarified.As a result,there were significant differences in the degradation efficiency of catalysts prepared with different small molecular carbon sources,which was related to the types of active sites.Density functional theory(DFT)and experiments results showed that the catalyst rich in C-O-C and FeN_(x)exhibited better catalytic activity,which may be attributed to the higher adsorption energy for PMS.The main active species for catalytic degradation of ofloxacin were identified as sulfate radical(SO_(4)^(·-))and hydroxyl radical(^(·)OH)by electron paramagnetic resonance(EPR)spectra.The introduction of different small molecular carbon sources can significantly affect the distribution and electronic structure of active sites on the catalyst surface,thereby regulating the generation and migration of radicals.展开更多
Most carbon-based catalysts utilized in Fenton-like systems face challenges such as structural instability,susceptibility to deactivation,and a tendency to disperse during operation.Wood-derived catalysts have garnere...Most carbon-based catalysts utilized in Fenton-like systems face challenges such as structural instability,susceptibility to deactivation,and a tendency to disperse during operation.Wood-derived catalysts have garnered considerable attention due to their well-defined structures,extensive pipeline networks,superior mechanical strength,and adaptability for device customization.However,there remains a paucity of research that systematically summarizes Fenton-like systems based on wood-derived catalysts.In this review,we first summarize the structural designs of wood-derived catalysts based on nano-metal sites and single-atom sites,while also outlining their advantages and limitations applied in Fenton-like systems.Furthermore,we evaluate catalytic modules of wood-derived catalysts for scale-up and continuous Fenton-like systems.Additionally,wood-inspired catalytic materials utilizing commercial textures and their applications in Fenton-like processes are also discussed.This paper aims to comprehensively explore the fundamental mechanisms(e.g.,characteristics of catalytic sites,catalytic performance,and mechanisms)of wood-based catalysts in Fenton-like chemistry,as well as their equipment designs and application scenarios,as well as providing the insights into future developments.展开更多
Although the powder Fenton-like catalysts have exhibited high catalytic performances towards pollutant degradation,they cannot be directly used for Fenton-like industrialization considering the problems of loss and re...Although the powder Fenton-like catalysts have exhibited high catalytic performances towards pollutant degradation,they cannot be directly used for Fenton-like industrialization considering the problems of loss and recovery.Therefore,the membrane fixation of catalyst is an important step to realize the actual application of Fenton-like catalysts.In this work,an efficient catalyst was developed with Co-N_(x)configuration facilely reconstructed on the surface of Co_(3)O_(4)(Co-N_(x)/Co_(3)O_(4)),which exhibited superior catalytic activity.We further fixed the highly efficient Co-N_(x)/Co_(3)O_(4)onto three kinds of organic membranes and one kind of inorganic ceramic membrane installing with the residual PMS treatment device to investigate its catalytic stability and sustainability.Results indicated that the inorganic ceramic membrane(CM)can achieve high water flux of 710 L m-2h-1,and the similar water flux can be achieved by Co-N_(x)/Co_(3)O_(4)/CM even without the pressure extraction.We also employed the Co-N_(x)/Co_(3)O_(4)/CM system to the wastewater secondary effluent,and the pollutant in complicated secondary effluent could be highly removed by the Co-N_(x)/Co_(3)O_(4)/CM system.This paper provides a new point of view for the application of metal-based catalysts with M-N_(x)coordination in catalytic reaction device.展开更多
The Fenton-like reaction between Cu^(2+)and H_(2)O_(2)was employed in chemical mechanical polishing to achieve efficient and high-quality processing of tungsten.The microstructure evolution and material removal rate o...The Fenton-like reaction between Cu^(2+)and H_(2)O_(2)was employed in chemical mechanical polishing to achieve efficient and high-quality processing of tungsten.The microstructure evolution and material removal rate of tungsten during polishing process were investigated via scanning electron microscopy,X-ray photoelectron spectroscopy,ultraviolet−visible spectrophotometry,and electrochemical experiments.The passivation behavior and material removal mechanism were discussed.Results show that the use of mixed H_(2)O_(2)+Cu(NO_(3))_(2)oxidant can achieve higher polishing efficiency and surface quality compared with the single oxidant Cu(NO_(3))_(2)or H_(2)O_(2).The increase in material removal rate is attributed to the rapid oxidation of W into WO_(3)via the chemical reaction between the substrate and hydroxyl radicals produced by the Fenton-like reaction.In addition,material removal rate and static etch rate exhibit significantly different dependencies on the concentration of Cu(NO_(3))_(2),while the superior oxidant for achieving the balance between polishing efficiency and surface quality is 0.5 wt.%H_(2)O_(2)+1.0 wt.%Cu(NO_(3))_(2).展开更多
Carbon dot(CD)is an edge-bound,nanometer-sized carbon material possessing unique optical and electronic properties,making it promising metal-free,environmentally benign.In this study,we identified a highly hydrophilic...Carbon dot(CD)is an edge-bound,nanometer-sized carbon material possessing unique optical and electronic properties,making it promising metal-free,environmentally benign.In this study,we identified a highly hydrophilic CD complexed with Fe(Ⅲ)via carboxyl groups to form CD-COOFeⅢ,which exhibited remarkably enhanced Fenton-like reaction performance boosted by visible light irradiation.CD-COOFeⅢenabled high activity in the visible region beyondλ>420 nm,and maintained stable oxidation efficiency in the presence of H_(2)O_(2)over at least ten cycles.The capacity of electrons transferred from photo-excited CD to reduce Fe(Ⅲ)was calculated to be 1.1 mmol/g of CD.Furthermore,the quantum yield(QY)of solarto-Fe(Ⅱ)conversion reached an impressive 87.7%.These findings not only suggest a viable strategy for efficient conversion of solar-to-chemical using a CD-COOFeⅢcomplex in visible light boosted Fenton-like oxidation reaction,but also provide insight for understanding the effect of nanosized artificial and/or natural carbon materials in iron recycling in a natural surface environment.展开更多
Asymmetric single-atom catalysts(ASACs)have attracted much attention owing to their excellent catalytic properties.However,the relationship between asymmetric coordination and the spin states of metal sites remains un...Asymmetric single-atom catalysts(ASACs)have attracted much attention owing to their excellent catalytic properties.However,the relationship between asymmetric coordination and the spin states of metal sites remains unclear.Additionally,the modulation of reactive oxygen species in Fenton-like reactions remains challenging.Herein,a novel strategy is reported for the rational design of highly loaded Co ASACs(CoN_(1)C_(2)/C_(2)N)immobilized on three-dimensional flower-like C_(2)N using an in situ-generated carbon defect method.In particular,the asymmetrically tricoordinated CoN_(1)C_(2)/C_(2)N exhibited excellent catalytic activity for sulfachloropyridazine degradation,with a turnover frequency of 36.8 min^(–1).Experimental results and theoretical calculations revealed that the electron spin state of the Co-active sites was transferred from the low-spin configuration(t_(2g)^(6)e_(g)^(1))to the high-spin configuration(t_(2g)^(5)e_(g)^(2))owing to asymmetric coordination.The high-spin Co 3d orbital in CoN_(1)C_(2)/C_(2)N possessed more unpaired electrons and therefore,had a strong ability to gain electrons from the O 2p orbitals of HSO_(5)^(–),boosting d-p orbital hybridization.More importantly,the spin-electron filling in theσ^(*)orbital of high-spin Co 3d−O 2p accelerated the desorption of^(*)SO_(5)•^(−),which acted as a rate-limiting step in the reaction,thus facilitating more^(1)O_(2)generation.This study provides an innovative synthetic route for practical ASACs and clarifies the critical relationship between structure and spin state,paving the way for advancements in environmental remediation and energy conversion applications.展开更多
In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ...In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.展开更多
In this paper,a novel method for investigating the particle-crushing behavior of breeding particles in a fusion blanket is proposed.The fractal theory and Weibull distribution are combined to establish a theoretical m...In this paper,a novel method for investigating the particle-crushing behavior of breeding particles in a fusion blanket is proposed.The fractal theory and Weibull distribution are combined to establish a theoretical model,and its validity was verified using a simple impact test.A crushable discrete element method(DEM)framework is built based on the previously established theoretical model.The tensile strength,which considers the fractal theory,size effect,and Weibull variation,was assigned to each generated particle.The assigned strength is then used for crush detection by comparing it with its maximum tensile stress.Mass conservation is ensured by inserting a series of sub-particles whose total mass was equal to the quality loss.Based on the crushable DEM framework,a numerical simulation of the crushing behavior of a pebble bed with hollow cylindrical geometry under a uniaxial compression test was performed.The results of this investigation showed that the particle withstands the external load by contact and sliding at the beginning of the compression process,and the results confirmed that crushing can be considered an important method of resisting the increasing external load.A relatively regular particle arrangement aids in resisting the load and reduces the occurrence of particle crushing.However,a limit exists to the promotion of resistance.When the strain increases beyond this limit,the distribution of the crushing position tends to be isotropic over the entire pebble bed.The theoretical model and crushable DEM framework provide a new method for exploring the pebble bed in a fusion reactor,considering particle crushing.展开更多
Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision...Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision process is formulated as a Markov decision process(MDP)model to maximize the modularity.Corresponding key partitioning constraints on parallel restoration are considered.Second,based on the partitioning objective and constraints,the reward function of the partitioning MDP model is set by adopting a relative deviation normalization scheme to reduce mutual interference between the reward and penalty in the reward function.The soft bonus scaling mechanism is introduced to mitigate overestimation caused by abrupt jumps in the reward.Then,the deep Q network method is applied to solve the partitioning MDP model and generate partitioning schemes.Two experience replay buffers are employed to speed up the training process of the method.Finally,case studies on the IEEE 39-bus test system demonstrate that the proposed method can generate a high-modularity partitioning result that meets all key partitioning constraints,thereby improving the parallelism and reliability of the restoration process.Moreover,simulation results demonstrate that an appropriate discount factor is crucial for ensuring both the convergence speed and the stability of the partitioning training.展开更多
The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environmen...The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environment and con-tribute to global climate change.However,there remain considerable research gaps in the accurate measurement of NCGs emissions from agricultural fields,hindering the development of effective emission reduction strategies.We improved an open-top dynamic chambers(OTDCs)system and evaluated the performance by comparing the measured and given fluxes of the NCGs.The results showed that the measured fluxes of NO,N_(2)O and NH_(3)were 1%,2%and 7%lower than the given fluxes,respectively.For the determination of NH_(3) concentration,we employed a stripping coil-ion chromatograph(SC-IC)analytical technique,which demonstrated an absorption efficiency for atmospheric NH_(3) exceeding 96.1%across sampling durations of 6 to 60 min.In the summer maize season,we utilized the OTDCs system to measure the exchange fluxes of NO,NH_(3),and N_(2)O from the soil in the North China Plain.Substantial emissions of NO,NH_(3) and N_(2)O were recorded following fertilization,with peaks of 107,309,1239 ng N/(m^(2)·s),respectively.Notably,significant NCGs emissions were observed following sus-tained heavy rainfall one month after fertilization,particularly with NH_(3) peak being 4.5 times higher than that observed immediately after fertilization.Our results demonstrate that the OTDCs system accurately reflects the emission characteristics of soil NCGs and meets the requirements for long-term and continuous flux observation.展开更多
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t...Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.展开更多
At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systema...At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater.展开更多
The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was invest...The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtained from conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton＇s reagent was the best among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable effectiveness of capillary suction time （CST） reduction efficiency of 47% can be achieved under test conditions of Fe^2＋/H2O2 = 20/125 mg/g DS （dry solid） and pH 6.0. The observation of floc-like particles after Fenton＇s reagent conditioning of alum sludge suggested that the mechanism of Fenton＇s reagent conditioning was different from that of polymer conditioning. In spite of the lower efficiency in the CST reduction of Fenton＇s reagent in alum sludge conditioning compared to that of polymer conditioning, Fenton＇s reagent offers a more environmentally safe option. Tiffs study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymers in sludge conditioning towards achieving a more sustainable sludge management strategy.展开更多
A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photo...A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photocatalysis（Vis-Photo）, for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50 mg/L Rhodamine B（Rh B） degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the Ti O2 lattice is the reason for the visible light photocatalytic activity of Co–Ti O2. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability,and almost no dissolution of Co2＋was found.展开更多
基金financially supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20114219110002)Fund from Coal Conversion and New Carbon Materials Hubei Key Laboratory(Wuhan University of Science and Technology)(No.WKDM201107)Educational Commission of Hubei Province of China(No.D20131107)
文摘In this study, Fe3O4nanoparticles（Fe3O4NPs） were successfully prepared via oxidation–precipitation method and characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FT-IR）. The characterization results indicated that Fe3O4 NPs with regular crystal structure and a narrow of diameters had been synthesized successfully and had high purity. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous Fe3O4 catalysts in the presence of H2O2. The response surface methodology（RSM） based on Box–Behnken design（BBD） was employed to design and optimize individual and interactive effects of the four main independent parameters（catalyst loading, initial p H, reaction temperature and H2O2concentration） on decolorization efficiency of Orange II. A significant quadratic model（p-value 〈0.0001, R2= 0.9369） was derived using analysis of variance（ANOVA）. Optimum conditions were catalyst loading of 1.5 g/L, initial p H of 2.7, reaction temperature of 42 8C and H2O2 concentration of 22 mmol/L, respectively. The predicted decolorization rate under the optimum conditions as determined by the proposed model was 99.55%. Confirmatory tests were carried out and the decolorization rate of 99.49% was observed under the optimum conditions, which agreed well with the model prediction.
基金supported by the National Natural Science Foundation of China(Nos.52300120 and 52070144)the Fundamental Research Funds for the Central Universities(No.22120240465).
文摘Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a novel pyrazine-based Fe-MOFs(MIL-101(Fe)-Pz)by substituting the 1,4-dicarboxybenzene acid ligands in typical MIL-101(Fe)with 2,5-pyrazinedicarboxylic acid(PzDC),in which sodium acetate was used as coordinative modulator to control the crystal size(2–3μm).The incorporation of Fe-pyridine N coordination structures originated from PzDC ligands gave MIL-101(Fe)-Pz narrowed band gap(1.45 eV)than MIL-101(Fe)(2.54 eV)resulting in improved visible-light adsorption capacity(λ>420 nm),and also increased the proportion of Fe(Ⅱ)in the Fe-clusters.Thus MIL-101(Fe)-Pz exhibited a synergistic enhanced photo-Fenton-like catalytic performance under visible-light irradiation.The MIL-101(Fe)-Pz/H_(2)O_(2)/Vis system could degrade 99%of sulfamethoxazolewithin 30min,whichwas 10-fold faster than that of the pristine MIL-101(Fe),it also effectively removed other organic micropollutants with high durability and stability.Mechanistic analysis revealed that the PzDC ligands substitution decreased the band gap of MIL-101(Fe),giving MIL-101(Fe)-Pz appropriate band structure(-0.40∼1.05 V vs.NHE)which can cover several light-driven process for the generation of reactive oxygen species,including Fe(Ⅲ)reduction and H_(2)O_(2) activation for accelerating•OH generation,as well as oxygen reduction reaction for generating H_(2)O_(2),O_(2)^(•−) and ^(1)O_(2).This study highlights the role of pyridine-N containing ligands in regulating the band structure of Fe-MOFs,providing valuable guidance for the design of Fe-MOFs photocatalysts.
基金supported by Gansu Cuihua Technology Co.,Ltd.(H2020292)Science and Technology Planning of Baiyin City,Fundamental Research Funds for the Central Universities (buctrc202208)+2 种基金Engineering Research Center of Non-metallic Minerals of Zhejiang Province and the Beijing Engineering Center for Hierarchical Catalysts. Central Government Guiding Funds for Local Science and Technology Development (2022ZY015)Nanjiang Technology Project(2023AB028)Open Laboratory of State Key Laboratory of Organic and Inorganic Composites (oic-202301006)。
文摘Coupling adsorption and in-situ Fenton-like oxidation process was developed for Methylene blue(MB) using refined iron-containing lowgrade attapulgite(ATP) clay, and the removal mechanism was investigated. The MB was initially adsorbed on the porous ATPs, and then the enriched MB was removed by the H2O2-assisted Fenton-like oxidation with the iron-containing ATP catalyst. Under optimal conditions, the ATP powder exhibits the maximum removal efficiency of 100% with negligible iron leaching(1.5 mg L^(-1)) and no sludge formation. Furthermore,polysulfone/ATP(PSF/ATP) pellets were fabricated through a water-induced phase separation process to construct a fixed-bed reactor(FBR) for continuous contaminant removal. For the first cycle, the maximum adsorption capacity was 15.5 L with an outlet MB concentration of1.973 mg L-1(< 2 mg L^(-1), GB4287-2012) using the PSF/ATP pellets containing 50.0 g of ATP powders, and the maximum Fenton-like oxidation capacity was 35.5 L with the outlet concentration of 0.831 mg L^(-1). After five cycles, the total treated volume of the MB solution was ca. 255 L, and the efficiency remained above 99%. After 10 h of continuous treatment towards practical resin industrial wastewater, the chemical oxygen demand(COD) removal efficiency was still measured at 83.05%, costing 0.398 $ m^(-3). These results demonstrate the practical applicability of iron-containing low-grade ATP clay for textile water treatment.
基金supported by National Natural Science Foundation of China(Nos.52170086,52300056)Natural Science Foundation of Shandong Province(Nos.ZR2021ME013,ZR202211280298)。
文摘In this study,different types of small molecular carbon sources such as melamine,dicyandiamine,pyrocatechol,and o-phenylenediamine were used to regulate the surface structures of iron/nitrogen/carbonbased composites(Fe-N/C),which were used to activate peroxymonosulfate(PMS).The relationship between different small molecular carbon sources and the electronic structure was investigated.The characteristics of metal-carrier interaction in the Fe-N/C were clarified.As a result,there were significant differences in the degradation efficiency of catalysts prepared with different small molecular carbon sources,which was related to the types of active sites.Density functional theory(DFT)and experiments results showed that the catalyst rich in C-O-C and FeN_(x)exhibited better catalytic activity,which may be attributed to the higher adsorption energy for PMS.The main active species for catalytic degradation of ofloxacin were identified as sulfate radical(SO_(4)^(·-))and hydroxyl radical(^(·)OH)by electron paramagnetic resonance(EPR)spectra.The introduction of different small molecular carbon sources can significantly affect the distribution and electronic structure of active sites on the catalyst surface,thereby regulating the generation and migration of radicals.
基金supported by National Natural Science Foundation of China(Nos.52170086,22308194,U22A20423)Natural Science Foundation of Shandong Province(No.ZR2021ME013)+4 种基金Shandong Provincial Excellent Youth(No.ZR2022YQ47)the doctor research start Foundation of Shaanxi University of Technology(No.SLGRCQD004)Science and Technology Innovation Team Project of Shaanxi Province(No.2025RS-CXTD-040)the General Special Scientific Research Program of the Shaanxi Provincial Department of Education(No.24JK0366)supported by funding from Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology。
文摘Most carbon-based catalysts utilized in Fenton-like systems face challenges such as structural instability,susceptibility to deactivation,and a tendency to disperse during operation.Wood-derived catalysts have garnered considerable attention due to their well-defined structures,extensive pipeline networks,superior mechanical strength,and adaptability for device customization.However,there remains a paucity of research that systematically summarizes Fenton-like systems based on wood-derived catalysts.In this review,we first summarize the structural designs of wood-derived catalysts based on nano-metal sites and single-atom sites,while also outlining their advantages and limitations applied in Fenton-like systems.Furthermore,we evaluate catalytic modules of wood-derived catalysts for scale-up and continuous Fenton-like systems.Additionally,wood-inspired catalytic materials utilizing commercial textures and their applications in Fenton-like processes are also discussed.This paper aims to comprehensively explore the fundamental mechanisms(e.g.,characteristics of catalytic sites,catalytic performance,and mechanisms)of wood-based catalysts in Fenton-like chemistry,as well as their equipment designs and application scenarios,as well as providing the insights into future developments.
基金supported by National Natural Science Fundation of China(Nos.52170086,22308194,U22A20423)Natural Science Foundation of Shandong Province(No.ZR2021ME013)+1 种基金Taishan Scholars Program of Shandong Province(No.tsqn202211012)Shandong Provincial Excellent Youth(No.ZR2022YQ47)。
文摘Although the powder Fenton-like catalysts have exhibited high catalytic performances towards pollutant degradation,they cannot be directly used for Fenton-like industrialization considering the problems of loss and recovery.Therefore,the membrane fixation of catalyst is an important step to realize the actual application of Fenton-like catalysts.In this work,an efficient catalyst was developed with Co-N_(x)configuration facilely reconstructed on the surface of Co_(3)O_(4)(Co-N_(x)/Co_(3)O_(4)),which exhibited superior catalytic activity.We further fixed the highly efficient Co-N_(x)/Co_(3)O_(4)onto three kinds of organic membranes and one kind of inorganic ceramic membrane installing with the residual PMS treatment device to investigate its catalytic stability and sustainability.Results indicated that the inorganic ceramic membrane(CM)can achieve high water flux of 710 L m-2h-1,and the similar water flux can be achieved by Co-N_(x)/Co_(3)O_(4)/CM even without the pressure extraction.We also employed the Co-N_(x)/Co_(3)O_(4)/CM system to the wastewater secondary effluent,and the pollutant in complicated secondary effluent could be highly removed by the Co-N_(x)/Co_(3)O_(4)/CM system.This paper provides a new point of view for the application of metal-based catalysts with M-N_(x)coordination in catalytic reaction device.
文摘The Fenton-like reaction between Cu^(2+)and H_(2)O_(2)was employed in chemical mechanical polishing to achieve efficient and high-quality processing of tungsten.The microstructure evolution and material removal rate of tungsten during polishing process were investigated via scanning electron microscopy,X-ray photoelectron spectroscopy,ultraviolet−visible spectrophotometry,and electrochemical experiments.The passivation behavior and material removal mechanism were discussed.Results show that the use of mixed H_(2)O_(2)+Cu(NO_(3))_(2)oxidant can achieve higher polishing efficiency and surface quality compared with the single oxidant Cu(NO_(3))_(2)or H_(2)O_(2).The increase in material removal rate is attributed to the rapid oxidation of W into WO_(3)via the chemical reaction between the substrate and hydroxyl radicals produced by the Fenton-like reaction.In addition,material removal rate and static etch rate exhibit significantly different dependencies on the concentration of Cu(NO_(3))_(2),while the superior oxidant for achieving the balance between polishing efficiency and surface quality is 0.5 wt.%H_(2)O_(2)+1.0 wt.%Cu(NO_(3))_(2).
基金the support of Natural Science Foundation of China(No.22276123)the Shanghai Engineering Research Center of Water Environment Simulation and Ecological Restoration(No.WESER-202201)the Postdoctoral Fellowship Program of CPSF(No.GZB20240456)。
文摘Carbon dot(CD)is an edge-bound,nanometer-sized carbon material possessing unique optical and electronic properties,making it promising metal-free,environmentally benign.In this study,we identified a highly hydrophilic CD complexed with Fe(Ⅲ)via carboxyl groups to form CD-COOFeⅢ,which exhibited remarkably enhanced Fenton-like reaction performance boosted by visible light irradiation.CD-COOFeⅢenabled high activity in the visible region beyondλ>420 nm,and maintained stable oxidation efficiency in the presence of H_(2)O_(2)over at least ten cycles.The capacity of electrons transferred from photo-excited CD to reduce Fe(Ⅲ)was calculated to be 1.1 mmol/g of CD.Furthermore,the quantum yield(QY)of solarto-Fe(Ⅱ)conversion reached an impressive 87.7%.These findings not only suggest a viable strategy for efficient conversion of solar-to-chemical using a CD-COOFeⅢcomplex in visible light boosted Fenton-like oxidation reaction,but also provide insight for understanding the effect of nanosized artificial and/or natural carbon materials in iron recycling in a natural surface environment.
文摘Asymmetric single-atom catalysts(ASACs)have attracted much attention owing to their excellent catalytic properties.However,the relationship between asymmetric coordination and the spin states of metal sites remains unclear.Additionally,the modulation of reactive oxygen species in Fenton-like reactions remains challenging.Herein,a novel strategy is reported for the rational design of highly loaded Co ASACs(CoN_(1)C_(2)/C_(2)N)immobilized on three-dimensional flower-like C_(2)N using an in situ-generated carbon defect method.In particular,the asymmetrically tricoordinated CoN_(1)C_(2)/C_(2)N exhibited excellent catalytic activity for sulfachloropyridazine degradation,with a turnover frequency of 36.8 min^(–1).Experimental results and theoretical calculations revealed that the electron spin state of the Co-active sites was transferred from the low-spin configuration(t_(2g)^(6)e_(g)^(1))to the high-spin configuration(t_(2g)^(5)e_(g)^(2))owing to asymmetric coordination.The high-spin Co 3d orbital in CoN_(1)C_(2)/C_(2)N possessed more unpaired electrons and therefore,had a strong ability to gain electrons from the O 2p orbitals of HSO_(5)^(–),boosting d-p orbital hybridization.More importantly,the spin-electron filling in theσ^(*)orbital of high-spin Co 3d−O 2p accelerated the desorption of^(*)SO_(5)•^(−),which acted as a rate-limiting step in the reaction,thus facilitating more^(1)O_(2)generation.This study provides an innovative synthetic route for practical ASACs and clarifies the critical relationship between structure and spin state,paving the way for advancements in environmental remediation and energy conversion applications.
基金Supported in part by Natural Science Foundation of Guangxi(2023GXNSFAA026246)in part by the Central Government's Guide to Local Science and Technology Development Fund(GuikeZY23055044)in part by the National Natural Science Foundation of China(62363003)。
文摘In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.
基金supported by Anhui Provincial Natural Science Foundation(2408085QA030)Natural Science Research Project of Anhui Educational Committee,China(2022AH050825)+3 种基金Medical Special Cultivation Project of Anhui University of Science and Technology(YZ2023H2C008)the Excellent Research and Innovation Team of Anhui Province,China(2022AH010052)the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology,China(2021yjrc51)Collaborative Innovation Program of Hefei Science Center,CAS,China(2019HSC-CIP006).
文摘In this paper,a novel method for investigating the particle-crushing behavior of breeding particles in a fusion blanket is proposed.The fractal theory and Weibull distribution are combined to establish a theoretical model,and its validity was verified using a simple impact test.A crushable discrete element method(DEM)framework is built based on the previously established theoretical model.The tensile strength,which considers the fractal theory,size effect,and Weibull variation,was assigned to each generated particle.The assigned strength is then used for crush detection by comparing it with its maximum tensile stress.Mass conservation is ensured by inserting a series of sub-particles whose total mass was equal to the quality loss.Based on the crushable DEM framework,a numerical simulation of the crushing behavior of a pebble bed with hollow cylindrical geometry under a uniaxial compression test was performed.The results of this investigation showed that the particle withstands the external load by contact and sliding at the beginning of the compression process,and the results confirmed that crushing can be considered an important method of resisting the increasing external load.A relatively regular particle arrangement aids in resisting the load and reduces the occurrence of particle crushing.However,a limit exists to the promotion of resistance.When the strain increases beyond this limit,the distribution of the crushing position tends to be isotropic over the entire pebble bed.The theoretical model and crushable DEM framework provide a new method for exploring the pebble bed in a fusion reactor,considering particle crushing.
基金funded by the Beijing Engineering Research Center of Electric Rail Transportation.
文摘Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision process is formulated as a Markov decision process(MDP)model to maximize the modularity.Corresponding key partitioning constraints on parallel restoration are considered.Second,based on the partitioning objective and constraints,the reward function of the partitioning MDP model is set by adopting a relative deviation normalization scheme to reduce mutual interference between the reward and penalty in the reward function.The soft bonus scaling mechanism is introduced to mitigate overestimation caused by abrupt jumps in the reward.Then,the deep Q network method is applied to solve the partitioning MDP model and generate partitioning schemes.Two experience replay buffers are employed to speed up the training process of the method.Finally,case studies on the IEEE 39-bus test system demonstrate that the proposed method can generate a high-modularity partitioning result that meets all key partitioning constraints,thereby improving the parallelism and reliability of the restoration process.Moreover,simulation results demonstrate that an appropriate discount factor is crucial for ensuring both the convergence speed and the stability of the partitioning training.
基金supported by the National Key Research and Develop-ment Program(No.2022YFC3701103)the National Natural Science Foundation of China(Nos.42130714 and 41931287).
文摘The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environment and con-tribute to global climate change.However,there remain considerable research gaps in the accurate measurement of NCGs emissions from agricultural fields,hindering the development of effective emission reduction strategies.We improved an open-top dynamic chambers(OTDCs)system and evaluated the performance by comparing the measured and given fluxes of the NCGs.The results showed that the measured fluxes of NO,N_(2)O and NH_(3)were 1%,2%and 7%lower than the given fluxes,respectively.For the determination of NH_(3) concentration,we employed a stripping coil-ion chromatograph(SC-IC)analytical technique,which demonstrated an absorption efficiency for atmospheric NH_(3) exceeding 96.1%across sampling durations of 6 to 60 min.In the summer maize season,we utilized the OTDCs system to measure the exchange fluxes of NO,NH_(3),and N_(2)O from the soil in the North China Plain.Substantial emissions of NO,NH_(3) and N_(2)O were recorded following fertilization,with peaks of 107,309,1239 ng N/(m^(2)·s),respectively.Notably,significant NCGs emissions were observed following sus-tained heavy rainfall one month after fertilization,particularly with NH_(3) peak being 4.5 times higher than that observed immediately after fertilization.Our results demonstrate that the OTDCs system accurately reflects the emission characteristics of soil NCGs and meets the requirements for long-term and continuous flux observation.
基金Supported by the National Natural Science Foundation of China under Grant No.51975138the High-Tech Ship Scientific Research Project from the Ministry of Industry and Information Technology under Grant No.CJ05N20the National Defense Basic Research Project under Grant No.JCKY2023604C006.
文摘Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.
基金supported by the National Natural Science Foundation of China(Project No.42307555).
文摘At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater.
基金The first author would like to appreciate Ministry of Higher Education, Missions Department, Egypt for the fi- nancial support granted through Channel Scheme Mission.
文摘The use of Fenton＇s reagent （Fe^2＋/H2O2） and Fenton-like reagents containing transition metals of Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ）, and Mn（Ⅱ） for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtained from conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton＇s reagent was the best among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable effectiveness of capillary suction time （CST） reduction efficiency of 47% can be achieved under test conditions of Fe^2＋/H2O2 = 20/125 mg/g DS （dry solid） and pH 6.0. The observation of floc-like particles after Fenton＇s reagent conditioning of alum sludge suggested that the mechanism of Fenton＇s reagent conditioning was different from that of polymer conditioning. In spite of the lower efficiency in the CST reduction of Fenton＇s reagent in alum sludge conditioning compared to that of polymer conditioning, Fenton＇s reagent offers a more environmentally safe option. Tiffs study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymers in sludge conditioning towards achieving a more sustainable sludge management strategy.
基金supported by the Fundamental Research Funds for the Central Universities(No.CDJXS12210002)the Major Project Foundation of Science and Technology Innovation in Minister of Education(No.708071)+2 种基金the Financial Supports of the National Natural Science Foundation of China(No.51108483)Natural Science Foundation Project of CQ CSTC(No.cstcjjA 20002)the 111 Project(No.B13041)
文摘A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photocatalysis（Vis-Photo）, for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50 mg/L Rhodamine B（Rh B） degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the Ti O2 lattice is the reason for the visible light photocatalytic activity of Co–Ti O2. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability,and almost no dissolution of Co2＋was found.
