Non-thermal plasma(NTP)is considered to be a promising technology for the removal of volatile organic compounds;however,its application is limited by low CO_(2) selectivity and undesirable by-products.To overcome thes...Non-thermal plasma(NTP)is considered to be a promising technology for the removal of volatile organic compounds;however,its application is limited by low CO_(2) selectivity and undesirable by-products.To overcome these issues,this paper discusses the degradation of chlorobenzene(CB)in systems of NTP coupled with catalysts,and the influence of catalyst locations in the NTP was investigated.In addition,the interaction between plasma and catalyst was also explored.The results indicated that the degradability of CB was remarkably improved through the combination of NTP with catalysts,and the formation of ozone was effectively inhibited.The degradation efficiency increased from 33.9%to 79.6%at 14 kV in the NTPcatalytic system,while the ozone concentration decreased from 437 to 237 mg m^(-3),and the degradation efficiency of in plasma catalysis(IPC)systems was superior to that of the post plasma catalysis system,while the inhibition ability of ozone exhibited an opposing trend.In the IPC system,the degradation efficiency was 87.7%at 14 k V,while the ozone concentration was151 mg m^(-3).Besides,the plasma did not destroy the pore structure and crystal structure of the catalyst,but affected the surface morphology and redox performance of the catalyst.Thus,NTP coupled catalytic system could improve the degradation performance of CB.Furthermore,the plasma discharge characteristics played a major role in the NTP synergistic catalytic degradation of CB.Finally,based on the experiment analysis results,the general reaction mechanism of CB degradation in an IPC reaction system was proposed.展开更多
This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentratio...This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentration on CB degradation were determined.The degradation effciency of CB was almost 100% with an initial CB concentration of 50 mg/L,current density 15 mA/cm2,initial pH 10,electrolyte concentration 0.1 mol/L,and temperature 25°C after 90 min of reaction.Under the same conditions,the degradation effciency of CB was only 51% by electrochemical (EC) process,which showed that electro-heterogeneous catalysis was more effcient than EC alone.The analysis results of Purge-and-Trap chromatography-mass spectrometry (P&T/GC/MS) and ion chromatography (IC) indicated that in the reaction process,the initial .OH attack could occur at the C-Cl bond of CB,yielding phenol and biphenyl with the release of Cl-.Further oxidation of phenol and biphenyl produced ρ-Vinylbenzoic acid and hydroquinol.Finally,the compounds were oxidized to butenedioic acid and other small-molecule acids.展开更多
Isobaric vapor-liquid equilibrium(VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a mo...Isobaric vapor-liquid equilibrium(VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a modified Rose-Williams still. Gas chromatography was used to analyze the compositions of the samples and no azeotropic behavior was found. All of the measured VLE values were checked by the semi-empirical method proposed by Herington and the point-to-point Van Ness test method modified by Fredenslund. The experimental data were correlated by using the Wilson, the non-random two-liquid and universal quasi-chemical activity coefficient models. The corresponding parameters for the three models were obtained.展开更多
The thermal decomposition of Cyclic Diperoxide of Benzaldehyde 3,6-diphenyl-1,2,4,5-tetroxane, (DFT) in chlorobenzene solution in the studied temperature range (130°C - 166°C) satisfactorily satisfies a firs...The thermal decomposition of Cyclic Diperoxide of Benzaldehyde 3,6-diphenyl-1,2,4,5-tetroxane, (DFT) in chlorobenzene solution in the studied temperature range (130°C - 166°C) satisfactorily satisfies a first order law up to 60% conversions of diperoxide. DFT would decompose through a mechanism in stages and initiated by the homolytic breakdown of one of the peroxidic bonds of the molecule, with the formation of the corresponding intermediate biradical. The concentration studied was very low, so that the effects of secondary reactions of decomposition induced by free radicals originated in the reaction medium can be considered minimal or negligible. The activation parameters for the unimolecular thermal decomposition reaction of the DFT are ΔH# = 30.52 ± 0.3 kcal·mol-1 and ΔS# = -6.38 ± 0.6 cal·mol-1 K-1. The support for a step-by-step mechanism instead of a process concerted is made by comparison with the theoretically calculated activation energy for the thermal decomposition of 1,2,4,5-tetroxane.展开更多
Here,a metal-organic framework(MOF)-templated strategy was applied to synthesize the CoCeO_(x) bimetallic catalysts by calcining Co partially-substituted Ce-UiO-66.It is indicated that the substituted Co limited Ce ca...Here,a metal-organic framework(MOF)-templated strategy was applied to synthesize the CoCeO_(x) bimetallic catalysts by calcining Co partially-substituted Ce-UiO-66.It is indicated that the substituted Co limited Ce cations in Ce-UiO-66 framework,which affects its growth and structure crystallinity to some extent.After pyrolysis treatment,the derived bimetallic oxide(CoCeO_(x)-M)can basically keep the octahedral structure and the surface area is much higher than the bulk metal composite oxide(CoCeO_(x)-B)prepared by traditional coprecipitation.Results reveal that CoCeO_(x)-M performs the best chlorobenzene degradation capacity,superior stability and vapor tolerance compared with those of CeO_(2)-M(derived from Ce-UiO-66)and CoCeO_(x)-B.At the same time,it is favorable to inhibit the formation of CO during the oxidation reaction.The superior catalytic performance of CoCeO_(x)-M is attributed to a good dispersion of metal cations,high surface area and active oxygen concentration,and good redox property.Moreover,the formation of organic byproducts especially chlorinated organics can be obviously prohibited over CoCeO_(x)-M compared with that of CeO_(2)-M.Mechanism study reveals that chlorobenzene dissociates on the surface of CoCeO_(x)-M to form carboxylates such as acetate species,maleate and phenolate before finally oxidized into CO_(2),H_(2)O,and HCl.The present work poses new insights into the fabrication of efficient catalysts for industrial CVOC purification.展开更多
In this work,hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH_(4))_(2)C_(2)O_(4)as a novel nitroge...In this work,hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH_(4))_(2)C_(2)O_(4)as a novel nitrogen-doping agent.Physicochemical properties of NPCK-x were characterized by Brunauer-Emmett-Teller,field emission scanning electron microscopy,X-ray diffraction,Raman microscope,elemental analysis,and X-ray photoelectron spectroscopy.Results showed that the NPCK-x samples possessed large surface areas (maximum:2875 m^(2)/g),hierarchical porous structures,and high degree of disorder.N-containing functional groups decomposed during activation process,which could be the dominant reason for appearance of abundant mesopores and well-developed pore structure.Dynamic chlorobenzene adsorption experiments demonstrated that carbon materials with(NH_(4))_(2)C_(2)O_(4)modification exhibited higher adsorption capacity (maximum:1053 mg/g) than those without modification (maximum:723 mg/g).The reusability studies of chlorobenzene indicated that the desorption efficiency of (NH_(4))_(2)C_(2)O_(4)modified porous carbon reached90.40%after thermal desorption at 100℃ under N2atmosphere.Thomas model fitting results exhibited that the existence of mesopores accelerated the diffusion rate of chlorobenzene in porous carbon.Moreover,Grand Canonical Monte Carlo simulation was conducted to verify that micropores with pore sizes of 1.2–2 nm of the optimized porous carbon were the best adsorption sites for chlorobenzene and mesopores with pore sizes of 2–5 nm were also highly active sites for chlorobenzene adsorption.展开更多
Despite the large emission of chlorinated volatile organic compounds(CVOCs)into the atmosphere,the ultimate fate of these compounds remains largely unknown.Herein,we explore the photochemical conversion of an importan...Despite the large emission of chlorinated volatile organic compounds(CVOCs)into the atmosphere,the ultimate fate of these compounds remains largely unknown.Herein,we explore the photochemical conversion of an important class of CVOCs,namely chlorobenzene(CB),on mineralα-Fe_(2)O_(3)particulates under atmospheric relevant conditions.A series of chamber reactions composed of the CB with/without SO_(2)or NO_(2)are performed,followed by in situ diffuse reflectance infrared Fourier transform spectroscopy measurements and density functional theory calculations.We show that CB can be considerably degraded byα-Fe_(2)O_(3)under light irradiation,whereas the reaction is markedly suppressed by adding SO_(2)or NO_(2)owing to their competitive adsorption and surface acidification.In particular,we discover that CB can be ultimately converted into polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)under dark state or light irradiation,suggesting a possible origin of atmospheric PCDD/Fs from this overlooked photochemical source.展开更多
Chlorobenzene removal was investigated in a non-thermal plasma reactor using CeO_2/HZSM-5catalysts.The performance of catalysts was evaluated in terms of removal and energy efficiency.The decomposition products of chl...Chlorobenzene removal was investigated in a non-thermal plasma reactor using CeO_2/HZSM-5catalysts.The performance of catalysts was evaluated in terms of removal and energy efficiency.The decomposition products of chlorobenzene were analyzed.The results show that CeO_2/HZSM-5 exhibited a good catalytic activity,which resulted in enhancements of chlorobenzene removal,energy efficiency,and the formation of lower amounts of by-products.With regards to CO_2 selectivity,the presence of catalysts favors the oxidation of by-products,leading to a higher CO_2 selectivity.With respect to ozone,which is considered as an unavoidable by-product in air plasma reactors,a noticeable decrease in its concentration was observed in the presence of catalysts.Furthermore,the stability of the catalyst was investigated by analyzing the evolution of conversion in time.The experiment results indicated that CeO_2/HZSM-5 catalysts have excellent stability:chlorobenzene conversion only decreased from 78%to 60%after 75 hr,which means that the CeO_2/HZSM-5 suffered a slight deactivation.Some organic compounds and chlorinated intermediates were adsorbed or deposited on the catalysts surface as shown by the results of Fourier Transform Infrared(FT-IR) spectroscopy,scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy(EDS) analyses of the catalyst before and after the reaction,revealing the cause of catalyst deactivation.展开更多
In this paper,MCM-41 was synthesized by a soft template technique and MCM-41 supported CuO-CeO2 nano-sized catalysts with different Cu/Ce molar ratios were prepared by a deposition-precipitation method.N2 adsorption,H...In this paper,MCM-41 was synthesized by a soft template technique and MCM-41 supported CuO-CeO2 nano-sized catalysts with different Cu/Ce molar ratios were prepared by a deposition-precipitation method.N2 adsorption,HRTEM-EDS,H2-TPR,XPS characterization,as well as catalytic activity and durability tests for the catalytic combustion of chlorobenzene(CB)were conducted to explore the relationship between the structure and catalytic performance of the catalysts.It is revealed that cuCe(6:1)/MCM-41 has the highest activity and can completely catalyze the degradation of CB at 260℃.The reasons for the high activity of the catalysts are as follows:MCM-41,a type of mesoporous material which has large pore size and large specific surface area,is suitable as a catalyst carrier.The average diameter of nano-sized CuO and CeO2 particles is about 3-5 nm and adding CeO2 improves the dispersion of active component CuO,which are highly and evenly dispersed on the surface of MCM-41.Characterization results also explain why MCM-41 supported CuO-CeO2 with appropriate proportion can highly enhance the catalytic activity.The reason is that CeO2 acting as an oxygen-rich material can improve the mobility of oxygen species through continuous redox between Ce4^+and Ce3^+,and improve the catalytic performance of CuO for CB combustion.Besides,CuCe(6:1)/MCM-41 also displays good durability for CB combustion,both in the humid condition and in the presence of benzene,making it a promising catalytic material for the elimination of chlorinated VOCs.展开更多
Nb doped MnCe0.2Ox complex oxides catalysts prepared via a homogeneous precipitation method were investigated for synergistic catalytic removal of NOx and chlorobenzene(CB)at low temperatures.The MnNb0.4Ce0.2Ox cataly...Nb doped MnCe0.2Ox complex oxides catalysts prepared via a homogeneous precipitation method were investigated for synergistic catalytic removal of NOx and chlorobenzene(CB)at low temperatures.The MnNb0.4Ce0.2Ox catalyst with a molar ratio of Nb/Mn=0.4 exhibits excellent activity and the NOx and CB removal efficiency reaches 94.5%and 96%at 220℃,respectively.Furthermore,the NOx and CB removal efficiency of MnNb0.4Ce0.2Ox still remains above 80%after injecting 300 ppm SO2 and 7 vol%H2 O for 36 h.In addition,the presence of CB and NOx+NH3 can improve the NOx and CB removal efficiency of MnNb0.4Ce0.2Ox,respectively.The analysis results from N2-BET,Py-IR,H2-TPR and NH3-TPD reveal that the introduction of Nb increases the average pore size,pore volume and surface area,promoted the growth of Lewis acid amount obviously,and enhances redox ability of MnCe0.2Ox at 100-250℃.Moreover,the molecular migration process of NOx,NH3,CB and SO2 in NH3-SCR and CB oxidation reaction over MnNb0.4Ce0.2Ox catalysts were systematically studied.In situ DRIFTS,FT-IR and XPS also confirm that the adsorption of sulfate species and SO2 on the surface of MnNb0.4Ce0.2Ox is inhibited effectively by the introduction of Nb in the presence of SO2 and H2 O.Moreover,Nb additives also enhance the structural stability of MnNb0.4Ce0.2Ox,due to the interactions among Mn,Nb and Ce.The NH3-TPD,H2-TPR and in situ DRIFTS results also confirm that the MnNb0.4Ce0.2Ox still retains abundant acid sites and high redox ability in the presence of SO2 and H2O.In summary,MnNb0.4Ce0.2Ox catalysts represent a promising and effective candidate for controlling NOx and CB at low temperatures.展开更多
The photocatalytic oxidation of gaseous chlorobenzene(CB) by the 365 nm-induced photocatalyst La/N–Ti O2, synthesized via a sol–gel and hydrothermal method, was evaluated. Response surface methodology(RSM) was used ...The photocatalytic oxidation of gaseous chlorobenzene(CB) by the 365 nm-induced photocatalyst La/N–Ti O2, synthesized via a sol–gel and hydrothermal method, was evaluated. Response surface methodology(RSM) was used to model and optimize the conditions for synthesis of the photocatalyst. The optimal photocatalyst was 1.2La/0.5N–Ti O2(0.5) and the effects of La/N on crystalline structure, particle morphology, surface element content, and other structural characteristics were investigated by XRD(X-ray diffraction), TEM(Transmission Electron Microscopy), FTIR(Fourier transform infrared spectroscopy), UV–vis(Ultraviolet–visible spectroscopy), and BET(Brunauer Emmett Teller). Greater surface area and smaller particle size were produced with the co-doped Ti O2 nanotubes than with reference Ti O2. The removal of CB was effective when performed using the synthesized photocatalyst,though it was less efficient at higher initial CB concentrations. Various modified Langmuir-Hinshelwood kinetic models involving the adsorption of chlorobenzene and water on different active sites were evaluated. Fitting results suggested that competitive adsorption caused by water molecules could not be neglected, especially for environments with high relative humidity. The reaction intermediates found after GC–MS(Gas chromatography–mass spectrometry) analysis indicated that most were soluble, low-toxicity, or both. The results demonstrated that the prepared photocatalyst had high activity for VOC(volatile organic compounds) conversion and may be used as a pretreatment prior to biopurification.展开更多
Biotrickling filters(BTFs) for hydrophobic chlorobenzene(CB) purification are limited by mass transfer and biodegradation. The CB mass transfer rate could be improved by 150 mg/L rhamnolipids. This study evaluated the...Biotrickling filters(BTFs) for hydrophobic chlorobenzene(CB) purification are limited by mass transfer and biodegradation. The CB mass transfer rate could be improved by 150 mg/L rhamnolipids. This study evaluated the combined use of Fe^(3+) and Zn^(2+) to enhance biodegradation in a BTF over 35 day. The effects of these trace elements were analysed under different inlet concentrations(250, 600, 900, and 1200 mg/L) and empty bed residence times(EBRTs;60, 45, and 32 sec). Batch experiments showed that the promoting effects of Fe^(3+)/Zn^(2+) on microbial growth and metabolism were highest for 3 mg/L Fe^(3+) and 2 mg/L Zn^(2+), followed by 2 mg/L Zn^(2+), and lowest at 3 mg/L Fe^(3+). Compared to BTF in the absence of Fe^(3+) and Zn^(2+), the average CB elimination capacity and removal efficiency in the presence of Fe^(3+) and Zn^(2+) increased from 61.54 to 65.79 g/(m 3 hr) and from 80.93% to 89.37%, respectively, at an EBRT of 60 sec. The average removal efficiency at EBRTs of 60, 45, and 32 sec increased by 2.89%, 5.63%, and 11.61%, respectively. The chemical composition(proteins(PN), polysaccharides(PS)) and functional groups of the biofilm were analysed at 60, 81, and 95 day. Fe^(3+) and Zn^(2+) significantly enhanced PN and PS secretion, which may have promoted CB adsorption and biodegradation. High-throughput sequencing revealed the promoting effect of Fe^(3+) and Zn^(2+) on bacterial populations. The combination of Fe^(3+) and Zn^(2+) with rhamnolipids was an efficient method for improving CB biodegradation in BTFs.展开更多
The synergetic abatement of multi-pollutants is one of the development trends of flue gas pollution control technology,which is still in the initial stage and facing many challenges.We developed a V_(2)O_(5)/TiO_(2)gr...The synergetic abatement of multi-pollutants is one of the development trends of flue gas pollution control technology,which is still in the initial stage and facing many challenges.We developed a V_(2)O_(5)/TiO_(2)granular catalyst and established the kinetic model for the simultaneous removal of NO and chlorobenzene(i.e.,an important precursor of dioxins).The granular catalyst synthesized using vanadyl acetylacetonate precursor showed good synergistic catalytic performance and stability.Although the SCR reaction of NO and the oxidation reaction of chlorobenzene mutually inhibited,the reaction order of each reaction was not considerably affected,and the pseudo-first-order reaction kinetics was still followed.The performance prediction of this work is of much value to the understanding and reasonable design of a catalytic system for multi-pollutants(i.e.,NO and dioxins)emission control.展开更多
The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity,malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations...The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity,malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water (P＜0.05). The experiments also revealed that a significant increase of MDA level in seedlings was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 μg · g-1 CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.展开更多
A family of Ce-doped LaCoO_(3) perovskites are presented as possible catalysts for Cl-VOCs elimination.These materials with different contents of Ce were obtained through the citrate and the reactive grinding methods....A family of Ce-doped LaCoO_(3) perovskites are presented as possible catalysts for Cl-VOCs elimination.These materials with different contents of Ce were obtained through the citrate and the reactive grinding methods.The insertion of Ce in the original perovskite structure favours the presence of Co^(2+)/Co^(3+) and Ce^(3+)/Ce^(4+) redox pairs and a higher content of oxygen vacancies that enhances the catalytic performance in chlorobenzene combustion based on differential kinetics studies.The family obtained by the grinding method presents a performance as high as that synthesized by citrate method.Thus,the reactive grinding is a feasible green chemistry alternative to obtain a catalyst with the same performance as that obtained from traditional methods.Finally,the stability of samples was evaluated under total combustion reaction conditions showing an excellent activity during 45 h time on stream.展开更多
Catalytic hydrodechlorination(HDC)is an innovative means of transforming chlorinated waste streams into a recyclable product. In this study,the gas phase HDC of chlorobenzene(CB)has been studied over bulk Pd and Ni an...Catalytic hydrodechlorination(HDC)is an innovative means of transforming chlorinated waste streams into a recyclable product. In this study,the gas phase HDC of chlorobenzene(CB)has been studied over bulk Pd and Ni and((8±1)wt%)Pd and Ni supported on activated carbon(AC),graphite,graphitic nanofibers(GNF),Al2O3,and SiO2.Catalyst activation was examined by temperature-programmed reduction(TPR)analysis and the activated catalysts characterized in terms of BET area,transmission electron microscopy,scanning electron microscopy,H2 chemisorption/temperature-programmed desorption,and X-ray diffraction measurements.Metal surface area(1-19 m 2 /g), TPR,and H2 uptake/release exhibited a dependence on both metal and support.The Pd system delivered specific HDC rates that were up to three orders of magnitude greater than that recorded for the Ni catalysts,a result that we link to the higher H2 diffusivity in Pd.HDC was 100%selective over Ni while Pd also produced cyclohexane(selectivity<4%)as a result of a combined HDC/hydrogenation.Bulk Pd outperformed carbon supported Pd but was less active than Pd on the oxide supports.In contrast,unsupported Ni presented no measurable activity when compared with supported Ni.The specific HDC rate was found to increase with decreasing metal surface area where spillover hydrogen served to enhance HDC performance.展开更多
Developing industrially moldable catalysts with harmonized redox performance and acidity is of great significance for the efficient disposal of chlorinated volatile organic compounds(CVOCs)in actual exhaust gasses.Her...Developing industrially moldable catalysts with harmonized redox performance and acidity is of great significance for the efficient disposal of chlorinated volatile organic compounds(CVOCs)in actual exhaust gasses.Here,commercial TiO_(2),typically used for molding catalysts,was chosen as the carrier to fabricate a series of Ce_(0.02)Mn_(0-0.24)TiO_(x) materials with different Mn doping ratios and employed for chlorobenzene(CB)destruction.The introduction of Mn remarkedly facilitated the synergistic effect of each element via the electron transfer processes:Ce^(3+)+Mn^(4+/3+)■Ce^(4+)+Mn^(3+/2+)and Mn^(4+/3+)+Ti^(4+)■Mn^(3+/2+)+Ti^(3+).These synergistic interactions in Ce_(0.02)Mn_(0.04-0.24)TiO_(x),especially Ce_(0.02)Mn_(0.16)TiO_(x),significantly elevated the active oxygen species,oxygen vacancies and redox properties,endowing the superior catalytic oxidation of CB.When the Mn doping amount increased to 0.24,a separate Mn_(3)O_(4) phase appeared,which in turn might weaken the synergistic effect.Furthermore,the acidity of Ce_(0.02)Mn_(0.04-0.24)TiO_(x) was decreased with the Mn doping,regulating the balance of redox property and acidity.Notably,Ce_(0.02)Mn_(0.16)TiO_(x) featured relatively abundant B-acid sites.Its coordinating redox ability and moderate acidity promoted the deep oxidation of CB and RCOOH-intermediates,as well as the rapid desorption of Cl species,thus obtaining sustainable reactivity.In comparison,CeTiO_(x) owned the strongest acidity,however,its poor redox property was not sufficient for the timely oxidative decomposition of the easier adsorbed CB,resulting in its rapid deactivation.This finding provides a promising strategy for the construction of efficient commercial molding catalysts to decompose the industrial-scale CVOCs.展开更多
An efficient solution-processable route employing Pb(Ac)2 as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported. The effect of different solution methods and de...An efficient solution-processable route employing Pb(Ac)2 as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported. The effect of different solution methods and device architectures on the morphologies of perovskite films were systematically investigated. Our results show that the planar perovskite layer fabricated by one-step solution method achieved fully covered and pinhole-free films. Further anti-solvent treatment using chlorobenzene (CB) promoted a perovskite film with highly smooth surfaces and enlarged grain sizes. Device fabricated from CB treated perovskite film achieved a best PCE of 15.80%, in comparison with 14.02%for the untreated device. These results evidently suggest a feasible route towards controlling the crystallization and morphology of planar heterojunction (PHJ) PSCs for improved efficiency.展开更多
Biodegradation of lower chlorinated benzenes(tri-, di-and monochlorobenzene) was assessed at a coastal aquifer contaminated with multiple chlorinated aromatic hydrocarbons. Field-derived microcosms, established with g...Biodegradation of lower chlorinated benzenes(tri-, di-and monochlorobenzene) was assessed at a coastal aquifer contaminated with multiple chlorinated aromatic hydrocarbons. Field-derived microcosms, established with groundwater from the source zone and amended with a mixture of lower chlorinated benzenes, evidenced biodegradation of monochlorobenzene(MCB) and 1,4-dichlorobenzene(1,4-DCB) in aerobic microcosms,whereas the addition of lactate in anaerobic microcosms did not enhance anaerobic reductive dechlorination. Aerobic microcosms established with groundwater from the plume consumed several doses of MCB and concomitantly degraded the three isomers of dichlorobenzene with no observable inhibitory effect. In the light of these results, we assessed the applicability of compound stable isotope analysis to monitor a potential aerobic remediation treatment of MCB and 1,4-DCB in this site. The carbon isotopic fractionation factors(ε) obtained from field-derived microcosms were-0.7‰ ± 0.1 ‰ and-1.0‰ ± 0.2 ‰ for MCB and1,4-DCB, respectively. For 1,4-DCB, the carbon isotope fractionation during aerobic biodegradation was reported for the first time. The weak carbon isotope fractionation values for the aerobic pathway would only allow tracing of in situ degradation in aquifer parts with high extent of biodegradation. However, based on the carbon isotope effects measured in this and previous studies, relatively high carbon isotope shifts(i.e., Δδ13C > 4.0 ‰) of MCB or 1,4-DCB in contaminated groundwater would suggest that their biodegradation is controlled by anaerobic reductive dechlorination.展开更多
基金supported by the National Key Research and Development Program of China(No.2018YFC1903100)Beijing Municipal Science and Technology Project Program(No.Z191100009119002)the State Environmental Protection Key Laboratory of Odor Pollution Control(No.20210504)。
文摘Non-thermal plasma(NTP)is considered to be a promising technology for the removal of volatile organic compounds;however,its application is limited by low CO_(2) selectivity and undesirable by-products.To overcome these issues,this paper discusses the degradation of chlorobenzene(CB)in systems of NTP coupled with catalysts,and the influence of catalyst locations in the NTP was investigated.In addition,the interaction between plasma and catalyst was also explored.The results indicated that the degradability of CB was remarkably improved through the combination of NTP with catalysts,and the formation of ozone was effectively inhibited.The degradation efficiency increased from 33.9%to 79.6%at 14 kV in the NTPcatalytic system,while the ozone concentration decreased from 437 to 237 mg m^(-3),and the degradation efficiency of in plasma catalysis(IPC)systems was superior to that of the post plasma catalysis system,while the inhibition ability of ozone exhibited an opposing trend.In the IPC system,the degradation efficiency was 87.7%at 14 k V,while the ozone concentration was151 mg m^(-3).Besides,the plasma did not destroy the pore structure and crystal structure of the catalyst,but affected the surface morphology and redox performance of the catalyst.Thus,NTP coupled catalytic system could improve the degradation performance of CB.Furthermore,the plasma discharge characteristics played a major role in the NTP synergistic catalytic degradation of CB.Finally,based on the experiment analysis results,the general reaction mechanism of CB degradation in an IPC reaction system was proposed.
基金the Science and Technology Department of Zhejiang Province (No.2006C13120).
文摘This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentration on CB degradation were determined.The degradation effciency of CB was almost 100% with an initial CB concentration of 50 mg/L,current density 15 mA/cm2,initial pH 10,electrolyte concentration 0.1 mol/L,and temperature 25°C after 90 min of reaction.Under the same conditions,the degradation effciency of CB was only 51% by electrochemical (EC) process,which showed that electro-heterogeneous catalysis was more effcient than EC alone.The analysis results of Purge-and-Trap chromatography-mass spectrometry (P&T/GC/MS) and ion chromatography (IC) indicated that in the reaction process,the initial .OH attack could occur at the C-Cl bond of CB,yielding phenol and biphenyl with the release of Cl-.Further oxidation of phenol and biphenyl produced ρ-Vinylbenzoic acid and hydroquinol.Finally,the compounds were oxidized to butenedioic acid and other small-molecule acids.
基金supported by State Key Laboratory of Chemical Engineering Foundation
文摘Isobaric vapor-liquid equilibrium(VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a modified Rose-Williams still. Gas chromatography was used to analyze the compositions of the samples and no azeotropic behavior was found. All of the measured VLE values were checked by the semi-empirical method proposed by Herington and the point-to-point Van Ness test method modified by Fredenslund. The experimental data were correlated by using the Wilson, the non-random two-liquid and universal quasi-chemical activity coefficient models. The corresponding parameters for the three models were obtained.
文摘The thermal decomposition of Cyclic Diperoxide of Benzaldehyde 3,6-diphenyl-1,2,4,5-tetroxane, (DFT) in chlorobenzene solution in the studied temperature range (130°C - 166°C) satisfactorily satisfies a first order law up to 60% conversions of diperoxide. DFT would decompose through a mechanism in stages and initiated by the homolytic breakdown of one of the peroxidic bonds of the molecule, with the formation of the corresponding intermediate biradical. The concentration studied was very low, so that the effects of secondary reactions of decomposition induced by free radicals originated in the reaction medium can be considered minimal or negligible. The activation parameters for the unimolecular thermal decomposition reaction of the DFT are ΔH# = 30.52 ± 0.3 kcal·mol-1 and ΔS# = -6.38 ± 0.6 cal·mol-1 K-1. The support for a step-by-step mechanism instead of a process concerted is made by comparison with the theoretically calculated activation energy for the thermal decomposition of 1,2,4,5-tetroxane.
基金Project supported by the National Natural Science Foundation of China(22106124,22276145)the Natural Science Foundation of Shaanxi Province(2021JQ-011).
文摘Here,a metal-organic framework(MOF)-templated strategy was applied to synthesize the CoCeO_(x) bimetallic catalysts by calcining Co partially-substituted Ce-UiO-66.It is indicated that the substituted Co limited Ce cations in Ce-UiO-66 framework,which affects its growth and structure crystallinity to some extent.After pyrolysis treatment,the derived bimetallic oxide(CoCeO_(x)-M)can basically keep the octahedral structure and the surface area is much higher than the bulk metal composite oxide(CoCeO_(x)-B)prepared by traditional coprecipitation.Results reveal that CoCeO_(x)-M performs the best chlorobenzene degradation capacity,superior stability and vapor tolerance compared with those of CeO_(2)-M(derived from Ce-UiO-66)and CoCeO_(x)-B.At the same time,it is favorable to inhibit the formation of CO during the oxidation reaction.The superior catalytic performance of CoCeO_(x)-M is attributed to a good dispersion of metal cations,high surface area and active oxygen concentration,and good redox property.Moreover,the formation of organic byproducts especially chlorinated organics can be obviously prohibited over CoCeO_(x)-M compared with that of CeO_(2)-M.Mechanism study reveals that chlorobenzene dissociates on the surface of CoCeO_(x)-M to form carboxylates such as acetate species,maleate and phenolate before finally oxidized into CO_(2),H_(2)O,and HCl.The present work poses new insights into the fabrication of efficient catalysts for industrial CVOC purification.
基金supported by the National Key Research and Development Program of China (No.2019YFC1805804)。
文摘In this work,hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH_(4))_(2)C_(2)O_(4)as a novel nitrogen-doping agent.Physicochemical properties of NPCK-x were characterized by Brunauer-Emmett-Teller,field emission scanning electron microscopy,X-ray diffraction,Raman microscope,elemental analysis,and X-ray photoelectron spectroscopy.Results showed that the NPCK-x samples possessed large surface areas (maximum:2875 m^(2)/g),hierarchical porous structures,and high degree of disorder.N-containing functional groups decomposed during activation process,which could be the dominant reason for appearance of abundant mesopores and well-developed pore structure.Dynamic chlorobenzene adsorption experiments demonstrated that carbon materials with(NH_(4))_(2)C_(2)O_(4)modification exhibited higher adsorption capacity (maximum:1053 mg/g) than those without modification (maximum:723 mg/g).The reusability studies of chlorobenzene indicated that the desorption efficiency of (NH_(4))_(2)C_(2)O_(4)modified porous carbon reached90.40%after thermal desorption at 100℃ under N2atmosphere.Thomas model fitting results exhibited that the existence of mesopores accelerated the diffusion rate of chlorobenzene in porous carbon.Moreover,Grand Canonical Monte Carlo simulation was conducted to verify that micropores with pore sizes of 1.2–2 nm of the optimized porous carbon were the best adsorption sites for chlorobenzene and mesopores with pore sizes of 2–5 nm were also highly active sites for chlorobenzene adsorption.
基金supported by the National Natural Science Foundation of China(No.22176169,52070168)the Key R&D Plan of Zhejiang Province(No.2023C03127)the Fundamental Research Funds for the Central Universities(No.226-2022-00150).
文摘Despite the large emission of chlorinated volatile organic compounds(CVOCs)into the atmosphere,the ultimate fate of these compounds remains largely unknown.Herein,we explore the photochemical conversion of an important class of CVOCs,namely chlorobenzene(CB),on mineralα-Fe_(2)O_(3)particulates under atmospheric relevant conditions.A series of chamber reactions composed of the CB with/without SO_(2)or NO_(2)are performed,followed by in situ diffuse reflectance infrared Fourier transform spectroscopy measurements and density functional theory calculations.We show that CB can be considerably degraded byα-Fe_(2)O_(3)under light irradiation,whereas the reaction is markedly suppressed by adding SO_(2)or NO_(2)owing to their competitive adsorption and surface acidification.In particular,we discover that CB can be ultimately converted into polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)under dark state or light irradiation,suggesting a possible origin of atmospheric PCDD/Fs from this overlooked photochemical source.
基金supported by the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT13096)the International S&T Cooperation Program of China(No.2011DFA92660)+2 种基金the National Natural Science Foundation of China(No.21276239)the Zhejiang Province Natural Science Foundation of China(No.LY14E080009)the International Cooperation Program of Zhejiang province(No.2013C24003)
文摘Chlorobenzene removal was investigated in a non-thermal plasma reactor using CeO_2/HZSM-5catalysts.The performance of catalysts was evaluated in terms of removal and energy efficiency.The decomposition products of chlorobenzene were analyzed.The results show that CeO_2/HZSM-5 exhibited a good catalytic activity,which resulted in enhancements of chlorobenzene removal,energy efficiency,and the formation of lower amounts of by-products.With regards to CO_2 selectivity,the presence of catalysts favors the oxidation of by-products,leading to a higher CO_2 selectivity.With respect to ozone,which is considered as an unavoidable by-product in air plasma reactors,a noticeable decrease in its concentration was observed in the presence of catalysts.Furthermore,the stability of the catalyst was investigated by analyzing the evolution of conversion in time.The experiment results indicated that CeO_2/HZSM-5 catalysts have excellent stability:chlorobenzene conversion only decreased from 78%to 60%after 75 hr,which means that the CeO_2/HZSM-5 suffered a slight deactivation.Some organic compounds and chlorinated intermediates were adsorbed or deposited on the catalysts surface as shown by the results of Fourier Transform Infrared(FT-IR) spectroscopy,scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy(EDS) analyses of the catalyst before and after the reaction,revealing the cause of catalyst deactivation.
基金Project supported by the National Natural Science Foundation of China(21577094)Zhejiang Public Welfare Technology Research Project(LGG19B070003)the Foundation of Science and Technology of Shaoxing City(2018C10019)。
文摘In this paper,MCM-41 was synthesized by a soft template technique and MCM-41 supported CuO-CeO2 nano-sized catalysts with different Cu/Ce molar ratios were prepared by a deposition-precipitation method.N2 adsorption,HRTEM-EDS,H2-TPR,XPS characterization,as well as catalytic activity and durability tests for the catalytic combustion of chlorobenzene(CB)were conducted to explore the relationship between the structure and catalytic performance of the catalysts.It is revealed that cuCe(6:1)/MCM-41 has the highest activity and can completely catalyze the degradation of CB at 260℃.The reasons for the high activity of the catalysts are as follows:MCM-41,a type of mesoporous material which has large pore size and large specific surface area,is suitable as a catalyst carrier.The average diameter of nano-sized CuO and CeO2 particles is about 3-5 nm and adding CeO2 improves the dispersion of active component CuO,which are highly and evenly dispersed on the surface of MCM-41.Characterization results also explain why MCM-41 supported CuO-CeO2 with appropriate proportion can highly enhance the catalytic activity.The reason is that CeO2 acting as an oxygen-rich material can improve the mobility of oxygen species through continuous redox between Ce4^+and Ce3^+,and improve the catalytic performance of CuO for CB combustion.Besides,CuCe(6:1)/MCM-41 also displays good durability for CB combustion,both in the humid condition and in the presence of benzene,making it a promising catalytic material for the elimination of chlorinated VOCs.
基金Project supported by the National Natural Science Foundation of China(51902166)the Natural Science Foundation of Jiangsu Province(BK20190786+6 种基金BK20170954)the Key Research and Development Program of Jiangsu Province(BE2018074)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(18KJB430019)the Startup Foundation for Introducing Talent of NUIST(2017r073)the USA NIH/NIAID(R21AI107415)the NSF-PREM program(DMR 1827745)the Philadelphia Foundation。
文摘Nb doped MnCe0.2Ox complex oxides catalysts prepared via a homogeneous precipitation method were investigated for synergistic catalytic removal of NOx and chlorobenzene(CB)at low temperatures.The MnNb0.4Ce0.2Ox catalyst with a molar ratio of Nb/Mn=0.4 exhibits excellent activity and the NOx and CB removal efficiency reaches 94.5%and 96%at 220℃,respectively.Furthermore,the NOx and CB removal efficiency of MnNb0.4Ce0.2Ox still remains above 80%after injecting 300 ppm SO2 and 7 vol%H2 O for 36 h.In addition,the presence of CB and NOx+NH3 can improve the NOx and CB removal efficiency of MnNb0.4Ce0.2Ox,respectively.The analysis results from N2-BET,Py-IR,H2-TPR and NH3-TPD reveal that the introduction of Nb increases the average pore size,pore volume and surface area,promoted the growth of Lewis acid amount obviously,and enhances redox ability of MnCe0.2Ox at 100-250℃.Moreover,the molecular migration process of NOx,NH3,CB and SO2 in NH3-SCR and CB oxidation reaction over MnNb0.4Ce0.2Ox catalysts were systematically studied.In situ DRIFTS,FT-IR and XPS also confirm that the adsorption of sulfate species and SO2 on the surface of MnNb0.4Ce0.2Ox is inhibited effectively by the introduction of Nb in the presence of SO2 and H2 O.Moreover,Nb additives also enhance the structural stability of MnNb0.4Ce0.2Ox,due to the interactions among Mn,Nb and Ce.The NH3-TPD,H2-TPR and in situ DRIFTS results also confirm that the MnNb0.4Ce0.2Ox still retains abundant acid sites and high redox ability in the presence of SO2 and H2O.In summary,MnNb0.4Ce0.2Ox catalysts represent a promising and effective candidate for controlling NOx and CB at low temperatures.
基金supported by the National Natural Science Foundation of China(No.21276239)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT13096)
文摘The photocatalytic oxidation of gaseous chlorobenzene(CB) by the 365 nm-induced photocatalyst La/N–Ti O2, synthesized via a sol–gel and hydrothermal method, was evaluated. Response surface methodology(RSM) was used to model and optimize the conditions for synthesis of the photocatalyst. The optimal photocatalyst was 1.2La/0.5N–Ti O2(0.5) and the effects of La/N on crystalline structure, particle morphology, surface element content, and other structural characteristics were investigated by XRD(X-ray diffraction), TEM(Transmission Electron Microscopy), FTIR(Fourier transform infrared spectroscopy), UV–vis(Ultraviolet–visible spectroscopy), and BET(Brunauer Emmett Teller). Greater surface area and smaller particle size were produced with the co-doped Ti O2 nanotubes than with reference Ti O2. The removal of CB was effective when performed using the synthesized photocatalyst,though it was less efficient at higher initial CB concentrations. Various modified Langmuir-Hinshelwood kinetic models involving the adsorption of chlorobenzene and water on different active sites were evaluated. Fitting results suggested that competitive adsorption caused by water molecules could not be neglected, especially for environments with high relative humidity. The reaction intermediates found after GC–MS(Gas chromatography–mass spectrometry) analysis indicated that most were soluble, low-toxicity, or both. The results demonstrated that the prepared photocatalyst had high activity for VOC(volatile organic compounds) conversion and may be used as a pretreatment prior to biopurification.
基金supported by the Fundamental Research Funds for the Central Universities(No.2018XKQYMS12)the Program for the National Natural Science Foundation of China(Nos.51778612 and 51974314)the Natural Science Foundation of Jiangsu Province(No.BK20191480)。
文摘Biotrickling filters(BTFs) for hydrophobic chlorobenzene(CB) purification are limited by mass transfer and biodegradation. The CB mass transfer rate could be improved by 150 mg/L rhamnolipids. This study evaluated the combined use of Fe^(3+) and Zn^(2+) to enhance biodegradation in a BTF over 35 day. The effects of these trace elements were analysed under different inlet concentrations(250, 600, 900, and 1200 mg/L) and empty bed residence times(EBRTs;60, 45, and 32 sec). Batch experiments showed that the promoting effects of Fe^(3+)/Zn^(2+) on microbial growth and metabolism were highest for 3 mg/L Fe^(3+) and 2 mg/L Zn^(2+), followed by 2 mg/L Zn^(2+), and lowest at 3 mg/L Fe^(3+). Compared to BTF in the absence of Fe^(3+) and Zn^(2+), the average CB elimination capacity and removal efficiency in the presence of Fe^(3+) and Zn^(2+) increased from 61.54 to 65.79 g/(m 3 hr) and from 80.93% to 89.37%, respectively, at an EBRT of 60 sec. The average removal efficiency at EBRTs of 60, 45, and 32 sec increased by 2.89%, 5.63%, and 11.61%, respectively. The chemical composition(proteins(PN), polysaccharides(PS)) and functional groups of the biofilm were analysed at 60, 81, and 95 day. Fe^(3+) and Zn^(2+) significantly enhanced PN and PS secretion, which may have promoted CB adsorption and biodegradation. High-throughput sequencing revealed the promoting effect of Fe^(3+) and Zn^(2+) on bacterial populations. The combination of Fe^(3+) and Zn^(2+) with rhamnolipids was an efficient method for improving CB biodegradation in BTFs.
基金We gratefully acknowledge the National Natural Science Foundation of China(Grant Nos.21876093 and 21777081).
文摘The synergetic abatement of multi-pollutants is one of the development trends of flue gas pollution control technology,which is still in the initial stage and facing many challenges.We developed a V_(2)O_(5)/TiO_(2)granular catalyst and established the kinetic model for the simultaneous removal of NO and chlorobenzene(i.e.,an important precursor of dioxins).The granular catalyst synthesized using vanadyl acetylacetonate precursor showed good synergistic catalytic performance and stability.Although the SCR reaction of NO and the oxidation reaction of chlorobenzene mutually inhibited,the reaction order of each reaction was not considerably affected,and the pseudo-first-order reaction kinetics was still followed.The performance prediction of this work is of much value to the understanding and reasonable design of a catalytic system for multi-pollutants(i.e.,NO and dioxins)emission control.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 20377043, 20225722,2004CB418506 and 20337010) the Ecological Experimental Station Foundation of the Chinese Academy of Sciences.
文摘The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity,malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water (P＜0.05). The experiments also revealed that a significant increase of MDA level in seedlings was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 μg · g-1 CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.
基金The financial support from Universidad Nacional de San Luis,CONICET,ANPCyT。
文摘A family of Ce-doped LaCoO_(3) perovskites are presented as possible catalysts for Cl-VOCs elimination.These materials with different contents of Ce were obtained through the citrate and the reactive grinding methods.The insertion of Ce in the original perovskite structure favours the presence of Co^(2+)/Co^(3+) and Ce^(3+)/Ce^(4+) redox pairs and a higher content of oxygen vacancies that enhances the catalytic performance in chlorobenzene combustion based on differential kinetics studies.The family obtained by the grinding method presents a performance as high as that synthesized by citrate method.Thus,the reactive grinding is a feasible green chemistry alternative to obtain a catalyst with the same performance as that obtained from traditional methods.Finally,the stability of samples was evaluated under total combustion reaction conditions showing an excellent activity during 45 h time on stream.
基金supported by the National Science Foundation through Grant CTS-0218591
文摘Catalytic hydrodechlorination(HDC)is an innovative means of transforming chlorinated waste streams into a recyclable product. In this study,the gas phase HDC of chlorobenzene(CB)has been studied over bulk Pd and Ni and((8±1)wt%)Pd and Ni supported on activated carbon(AC),graphite,graphitic nanofibers(GNF),Al2O3,and SiO2.Catalyst activation was examined by temperature-programmed reduction(TPR)analysis and the activated catalysts characterized in terms of BET area,transmission electron microscopy,scanning electron microscopy,H2 chemisorption/temperature-programmed desorption,and X-ray diffraction measurements.Metal surface area(1-19 m 2 /g), TPR,and H2 uptake/release exhibited a dependence on both metal and support.The Pd system delivered specific HDC rates that were up to three orders of magnitude greater than that recorded for the Ni catalysts,a result that we link to the higher H2 diffusivity in Pd.HDC was 100%selective over Ni while Pd also produced cyclohexane(selectivity<4%)as a result of a combined HDC/hydrogenation.Bulk Pd outperformed carbon supported Pd but was less active than Pd on the oxide supports.In contrast,unsupported Ni presented no measurable activity when compared with supported Ni.The specific HDC rate was found to increase with decreasing metal surface area where spillover hydrogen served to enhance HDC performance.
基金supported by the National Key R&D Program of China(No.2020YFC1910100)the National Natural Science Foundation of China(Nos.22006156 and 21876193)+1 种基金the Chengdu Science and Technology Bureau(No.2018-ZM01-00019-SN)the Youth Innovation Promotion Association CAS。
文摘Developing industrially moldable catalysts with harmonized redox performance and acidity is of great significance for the efficient disposal of chlorinated volatile organic compounds(CVOCs)in actual exhaust gasses.Here,commercial TiO_(2),typically used for molding catalysts,was chosen as the carrier to fabricate a series of Ce_(0.02)Mn_(0-0.24)TiO_(x) materials with different Mn doping ratios and employed for chlorobenzene(CB)destruction.The introduction of Mn remarkedly facilitated the synergistic effect of each element via the electron transfer processes:Ce^(3+)+Mn^(4+/3+)■Ce^(4+)+Mn^(3+/2+)and Mn^(4+/3+)+Ti^(4+)■Mn^(3+/2+)+Ti^(3+).These synergistic interactions in Ce_(0.02)Mn_(0.04-0.24)TiO_(x),especially Ce_(0.02)Mn_(0.16)TiO_(x),significantly elevated the active oxygen species,oxygen vacancies and redox properties,endowing the superior catalytic oxidation of CB.When the Mn doping amount increased to 0.24,a separate Mn_(3)O_(4) phase appeared,which in turn might weaken the synergistic effect.Furthermore,the acidity of Ce_(0.02)Mn_(0.04-0.24)TiO_(x) was decreased with the Mn doping,regulating the balance of redox property and acidity.Notably,Ce_(0.02)Mn_(0.16)TiO_(x) featured relatively abundant B-acid sites.Its coordinating redox ability and moderate acidity promoted the deep oxidation of CB and RCOOH-intermediates,as well as the rapid desorption of Cl species,thus obtaining sustainable reactivity.In comparison,CeTiO_(x) owned the strongest acidity,however,its poor redox property was not sufficient for the timely oxidative decomposition of the easier adsorbed CB,resulting in its rapid deactivation.This finding provides a promising strategy for the construction of efficient commercial molding catalysts to decompose the industrial-scale CVOCs.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.51572072 and 21402045)Wuhan Science and Technology Bureau of Hubei Province of China (No. 2013010602010209)+1 种基金Educational Commission of Hubei Province of China(No. D20141006)Department of Science & Technology of Hubei Province of China(No. 2015CFA118)
文摘An efficient solution-processable route employing Pb(Ac)2 as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported. The effect of different solution methods and device architectures on the morphologies of perovskite films were systematically investigated. Our results show that the planar perovskite layer fabricated by one-step solution method achieved fully covered and pinhole-free films. Further anti-solvent treatment using chlorobenzene (CB) promoted a perovskite film with highly smooth surfaces and enlarged grain sizes. Device fabricated from CB treated perovskite film achieved a best PCE of 15.80%, in comparison with 14.02%for the untreated device. These results evidently suggest a feasible route towards controlling the crystallization and morphology of planar heterojunction (PHJ) PSCs for improved efficiency.
基金supported by the Catalan Water Agency (No. CTN1900901)supported by the projects CGL2017–82331-R (Spanish Ministry of Economy and Competitiveness)2017SGR 1733 (Catalan Government)。
文摘Biodegradation of lower chlorinated benzenes(tri-, di-and monochlorobenzene) was assessed at a coastal aquifer contaminated with multiple chlorinated aromatic hydrocarbons. Field-derived microcosms, established with groundwater from the source zone and amended with a mixture of lower chlorinated benzenes, evidenced biodegradation of monochlorobenzene(MCB) and 1,4-dichlorobenzene(1,4-DCB) in aerobic microcosms,whereas the addition of lactate in anaerobic microcosms did not enhance anaerobic reductive dechlorination. Aerobic microcosms established with groundwater from the plume consumed several doses of MCB and concomitantly degraded the three isomers of dichlorobenzene with no observable inhibitory effect. In the light of these results, we assessed the applicability of compound stable isotope analysis to monitor a potential aerobic remediation treatment of MCB and 1,4-DCB in this site. The carbon isotopic fractionation factors(ε) obtained from field-derived microcosms were-0.7‰ ± 0.1 ‰ and-1.0‰ ± 0.2 ‰ for MCB and1,4-DCB, respectively. For 1,4-DCB, the carbon isotope fractionation during aerobic biodegradation was reported for the first time. The weak carbon isotope fractionation values for the aerobic pathway would only allow tracing of in situ degradation in aquifer parts with high extent of biodegradation. However, based on the carbon isotope effects measured in this and previous studies, relatively high carbon isotope shifts(i.e., Δδ13C > 4.0 ‰) of MCB or 1,4-DCB in contaminated groundwater would suggest that their biodegradation is controlled by anaerobic reductive dechlorination.
