Chlorinated antibiotics pose great challenges in efficient removal,while for the first time,this work greatly enhanced their electrocatalytic dechlorination performance by construction of non-noble metal Co_(3)O_(4)/g...Chlorinated antibiotics pose great challenges in efficient removal,while for the first time,this work greatly enhanced their electrocatalytic dechlorination performance by construction of non-noble metal Co_(3)O_(4)/g-C_(3)N_(4) heterojunctions to improve process cost-effectiveness.The Co_(3)O_(4)/g-C_(3)N_(4) heterojunction demonstrated an effective removal of 93.6%thiamphenicol(TAP)within 45 min,with the rate constant(0.0584 min^(-1))that was 2.4 and 2.8 times that of Co_(3)O_(4) and g-C_(3)N_(4) alone,respectively.The formation of heterojunctions facilitated electron transfer,enriched the electron density on Co_(3)O_(4),and enhanced the adsorption of pollutants as well as the desorption of degradation intermediates.The enhanced production of atomic hydrogen(H*)of Co_(3)O_(4)/g-C_(3)N_(4),which increased by 13.6-28.2 times,contributed more to pollutant removal(64.0%),much higher than that of Co_(3)O_(4)(37.3%)and g-C_(3)N_(4)(6.1%).The energy barrier for H_(2) formation on Co_(3)O_(4)/g-C_(3)N_(4)(0.75 eV)was higher than that on Co_(3)O_(4)(-1.84 eV),supporting that it could stabilize H*and inhibit the formation of H_(2).The Co_(3)O_(4)/g-C_(3)N_(4) heterojunction exhibited stable performance with less impact by pH and co-existing ions,and posed effectiveness for the dechlorination of typical chlorinated antibiotics.This study offers an efficient and sustainable strategy for constructing heterojunctions to enhance the performance of non-noble metal catalysts in electrocatalytic dechlorination.展开更多
The persistence of chlorinated alkanes in aquatic environments poses significant health risks due to its biotoxicity and high volatility,which contributes to both water and air pollution.This study investigates the ef...The persistence of chlorinated alkanes in aquatic environments poses significant health risks due to its biotoxicity and high volatility,which contributes to both water and air pollution.This study investigates the efficacy of carbon dioxide radical anion(CO_(2)·^(-))mediated advanced reduction processes(ARPs)for the reductive dechlorination of chlorinated alkanes using small molecular monocarboxylic acids(SMAs)under UV irradiation.The study focused on formic acid(HCOOH),acetic acid(CH_3COOH),and propionic acid(CH_3CH_(2)COOH)to generate CO_(2)·^(-),revealing that UV/HCOOH system exhibits a notably high chloroform(CF)degradation efficiency of 97.8%in 90 min.Kinetic studies indicated a linear relationship between the HCOOH concentrations and the observed reaction rate constants(k_(obs)),demonstrating that CO_(2)·^(-)production is crucial for CF degradation.Electron paramagnetic resonance spectroscopy identified CO_(2)·^(-)and hydroxyl radicals(HO·)as the active species,with the former playing a predominant role in CF degradation.The study also explored the influence of carbon chain length in SMAs on CF degradation,finding that longer chains decrease the degradation efficiency,potentially due to reduced UV activation.A higher reaction rate constant(k_(obs))under acidic conditions,with a marked decrease in efficiency as the pH exceeds 3.7,where HCOO^(-)becomes predominant.This study enhances our understanding of CO_(2)·^(-)mediated ARPs and explores potential applications in environmental remediation,providing insights into the pathways and mechanisms of CF degradation.The UV/SMAs systems offer advantages for practical applications,such as milder reaction conditions and higher efficiency compared to traditional methods.展开更多
The formation of disinfection by-products（DBPs） from the degradation of N,N-diethyl-3-methyl benzoyl amide（DEET） and ibuprofen（IBP） by the ultraviolet irradiation（UV）/chlorine process and subsequent post-chlor...The formation of disinfection by-products（DBPs） from the degradation of N,N-diethyl-3-methyl benzoyl amide（DEET） and ibuprofen（IBP） by the ultraviolet irradiation（UV）/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H_2O_2 process.The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H_2O_2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species U（RCS） and hydroxyl radicals（HO） in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50%after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine（TOCl）, respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H_2O_2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%–63% higher,Ulikely due to the generation of more DBP precursors from the attack of RCS, in addition to HO.展开更多
Benzophenones （BPs） are a class of widely used UV filters, which have been frequently detected within multiple environmental matrices. Disinfection is a necessary process in water treatment processes. The transforma...Benzophenones （BPs） are a class of widely used UV filters, which have been frequently detected within multiple environmental matrices. Disinfection is a necessary process in water treatment processes. The transformation behaviors and toxicity changes of 14 BP-type UV filters during chlorination disinfection treatment were investigated in this study. A new index, the acute toxicity formation potential, was proposed to evaluate the toxicity changes and potential risks of BP-type UV filters during chlorination treatment. It was found that 13 of 14 BP-type UV filters exhibited toxicity decreases in the chlorination disinfection process, more or less, while one showed a toxicity increase. The toxicity changes were dependent on substitution effects, such that 2,4-di-hydroxylated or 3-hydroxylated BPs exhibited significant toxicity decreases after chlorination treatment due to the ready cleavage of the aromatic ring. Importantly, the acute toxicity changes could be duplicated in an ambient water matrix.展开更多
Titanium dioxide （TiO2）, which is the widely used photo-catalyst, has been synthesized by simple hydrothermal solution containing tetrabntyl titanate and hydrofluoric acid. The synthesized product has been applied t...Titanium dioxide （TiO2）, which is the widely used photo-catalyst, has been synthesized by simple hydrothermal solution containing tetrabntyl titanate and hydrofluoric acid. The synthesized product has been applied to photo-degradation in aqueous phase of chlorinated solvents, namely tetra- chloroethene （PCE）, tdchloroethene （TCE） and 1,1,l-trichloroethane （TCA）. The photo-degradation results revealed that the degradation of these harmful chemicals was better in UV/synthesized TiO2 system compared to UV/commerciai P25 system and UV only system. The photo-catalytic efficiency of the synthesized TiO2 was 1.4, 1.8 and 3.0 folds higher compared to the commercial P25 for TCA, TCE and PCE degradation, respectively. Moreover, using nitrobenzene （NB） as a probe of hydroxyl radical （.OH）, the degradation rate was better over UV/synthesized TiO2, suggesting the high concentration of .OH generated in UV/synthesized TiO2 system. In addition, .OH concentration was confirmed by the strong peak displayed in EPR analysis over U~/synthesized TiO2 system. The characterization result using XRD and TEM showed that the synthesized TiO2 was in anatase form and consisted of well-defined sheet-shaped structures having a rectangular outline with a thickness of 4 rim, side length of 50 nm and width of 33 nra and a surface 90.3 m^2/g. XPS analysis revealed that ≡Ti-F bond was formed on the surface of the synthesized TiO2. The above results on both photocatalytic activity and the surface analysis demonstrated the good applicability of the synthesized TiO2 nano-sheets for the remediation of chlorinated solvent contaminated groundwater.展开更多
During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this ...During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this study,the impact of chlorination and UV modification on the physicochemical properties of polystyrene(PS)and polyvinyl chloride(PVC)were investigated,and the adsorption behavior of pefloxacin(PEF)before and after modificationwas examined.The effect of pH,ionic strength,dissolved organicmatter,heavymetal ions and other water environmental conditions on adsorption behavior was revealed.The results showed that PS had a higher adsorption capacity of PEF than PVC,and the modification increased the presence of O-containing functional groups in the MPs,thereby enhancing the adsorption capacity of both materials.Chlorination had a more significant impact on the physicochemical properties of MPs compared to UV irradiation within the same time period,leading to better adsorption performance of chlorination.The optimal pH for adsorption was found to be 6,and NaCl,sodium alginate and Cu2+would inhibit adsorption to varying degrees,among which the inhibition caused by pH was the strongest.Chlorination and UV modification would weaken the inhibitory effect of environmental factors on the adsorption of PEF by MPs.The main mechanisms of adsorption involved electrostatic interaction and hydrogen bonding.The study clarified the effects of modification on the physicochemical properties of MPs,providing reference for subsequent biotoxicity analysis and environmental protection studies.展开更多
Ultraviolet/persulfate (UV/PS) and Ultraviolet/hydrogen peroxide (UV/H_(2)O_(2)) have attracted much attention in recent years as advanced oxidation processes for water treatment.However,it is not all clear how these ...Ultraviolet/persulfate (UV/PS) and Ultraviolet/hydrogen peroxide (UV/H_(2)O_(2)) have attracted much attention in recent years as advanced oxidation processes for water treatment.However,it is not all clear how these two methods affect the formation of cyanogen chloride(CNCl) in the subsequent water chlorination process.In this study,it was found that both UV/H_(2)O_(2)and UV/PS pre-oxidation promoted the formation of CNCl in six actual water samples collected from urban rivers.Glycine,uric acid,arginine and histidine were investigated as the model compounds to explore the effects of different methods on the production of CNCl.The results showed that compared with chlorination alone,pre-oxidation by UV/H_(2)O_(2)and UV/PS can reduce the production of CNCl for glycine and uric acid by up to 95%during post-chlorination process.However,they can greatly promote the formation of CNCl for arginine and histidine by up to 120-fold.In a more detailed investigation,pre-oxidation of histidine formed highly reactive intermediates to chlorine,leading to increased CNCl formation and chlorine consumption.The results showed that the precursors of CNCl was altered after pre-oxidation,and need to be re-evaluated.展开更多
With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic ...With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic analysis of the chlorination roasting kinetics and proposes a new two-step chlorination roasting process that integrates thermodynamics for the recycling of LIB cathode materials.The activation energy for the chloride reaction was 88.41 kJ/mol according to thermogravimetric analysis–derivative thermogravimetry data obtained by using model-free,model-fitting,and Z(α)function(αis conversion rate).Results indicated that the reaction was dominated by the first-order(F1)model when the conversion rate was less than or equal to 0.5 and shifted to the second-order(F2)model when the conversion rate exceeded 0.5.Optimal conditions were determined by thoroughly investigating the effects of roasting temperature,roasting time,and the mass ratio of NH_(4)Cl to LiCoO_(2).Under the optimal conditions,namely 400℃,20 min,and NH_(4)Cl/LiCoO_(2)mass ratio of 3:1,the leaching efficiency of Li and Co reached 99.43% and 99.05%,respectively.Analysis of the roasted products revealed that valuable metals in LiCoO_(2)transformed into CoCl_(2) and LiCl.Furthermore,the reaction mechanism was elucidated,providing insights for the establishment of a novel low-temperature chlorination roasting technology based on a crystal structure perspective.This technology can guide the development of LIB recycling processes with low energy consumption,low secondary pollution,high recovery efficiency,and high added value.展开更多
Benzophenones（BPs）, a group of widely used UV filters, exert multiple, significant toxicity effects. The 11 BPs were selected as target compounds, and the photobacterium acute toxicity test and an index for acute to...Benzophenones（BPs）, a group of widely used UV filters, exert multiple, significant toxicity effects. The 11 BPs were selected as target compounds, and the photobacterium acute toxicity test and an index for acute toxicity formation potential（ATFP） were used to evaluate the toxicity variation of BPs before and after a photoinduction–chlorination disinfection process.Orthogonal experiments were performed at different pH values and chlorine dosages. The characteristics of ATFP values for 11 BPs after a photoinduction–chlorination process can be summarized as follows：（1） The ATFPs decreased as the hydroxyl group number increased in BPs molecules.（2） For those BPs with the same hydroxyl group number, the ATFPs were higher when the hydroxyl groups were located at the 3-or 4-position than those at the 2-position; the BPs with hydroxyl groups distributed on two benzene rings had higher ATFPs than those on one ring.（3） Introducing a methoxyl group and sulfonic acid group into BP molecules increased the ATFP values.（4） The ATFPs were p H-dependent, the values of which were lowest at the neutral condition and highest at the acid condition.（5） The ATFPs increased and then decreased as the chlorine dosage increased. The results can be used as a reference to scientifically evaluate the environmental fate and potential risk of BPs in photoinduction–chlorination disinfection processes.展开更多
Benzotriazole(BTA)-based A_(2)-A_1-D-A_1-A_(2)type wide-bandgap(WBG)non-fullerene acceptors(NFAs)have shown promising potential in indoor photovoltaic,and in-depth investigation of their structure-property relationshi...Benzotriazole(BTA)-based A_(2)-A_1-D-A_1-A_(2)type wide-bandgap(WBG)non-fullerene acceptors(NFAs)have shown promising potential in indoor photovoltaic,and in-depth investigation of their structure-property relationship is of great significance.Herein,we explored the chlorination effect of the side chain on the terminals.We introduced Cl atoms into the benzyl side chains in parent BTA5 to synthesize two NFAs,BTA5-Cl with mono-chlorinated benzyl groups and BTA5-2Cl containing bi-chlorinated benzyl groups.We chose D18-Cl with deep-energy levels and strong crystallinity to pair with these three acceptors,affording high photovoltage and photocurrent.With the stepwise chlorination,the open-circuit voltage(V_(OC))values decrease from 1.28,1.22,to 1.20 V,while the corresponding power conversion efficiencies(PCEs)improve from 5.07%,9.15%,to 10.96%.Compared with BTA5-based OSCs,introducing Cl atoms downshifts the energy levels and slightly increases the non-radiative energy loss(0.14<0.17<0.19 e V),resulting in a sequential decrease in VO C.However,more chlorine atom replacements produce more effective exciton dissociation,higher charge transfer,and balanced carrier mobility in the blend films,ultimately achieving better PCEs.This work indicates that chlorination of the benzyl group on the terminals can improve the device's performance,implying good application potential in indoor photovoltaics.展开更多
Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction m...Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).展开更多
Due to the lack of effective screening systems in the rare earth waste recycling industry,the composition of rare earth elements in rare earth waste is complex and difficult to separate.In response to such problems,by...Due to the lack of effective screening systems in the rare earth waste recycling industry,the composition of rare earth elements in rare earth waste is complex and difficult to separate.In response to such problems,by studying the reaction behavior between various elements in rare earth waste and cobalt chloride,we propose a process path for the separation and recovery of iron,cerium and other rare earth elements using cobalt chloride roasting.The experiments on simulated wastes show that the leaching rates of the Nd,Sm,Gd,Pr can reach 98.31%,94.5%,93.87%and 72.05%under the optimal process conditions,respectively.Ce and iron remain in the leaching residue in the form of CeO_(2)and CoFe_(2)O_(4),respectively.And through a simple magnetic separation process,CeO_(2)and CoFe_(2)O_(4)can be enriched in non-magnetic leaching residue and magnetic leaching residue,respectively.The cerium content in the leaching residue composed of cobalt ferrite is only 1.95%.Therefore,this method is beneficial to the separation and high-value utilization of iron,cerium,and other rare earth elements in the waste system.The research results can provide theoretical reference for the low-cost and high-value recovery of rare earth secondary resources.展开更多
基金supported by Natural Science Foundation of China(Nos.U23B20165 and 52170085)National Key R&D Program International Cooperation Project(No.2023YFE0108100)+1 种基金Key Project of Natural Science Foundation of Tianjin(No.21JCZDJC00320)Fundamental Research Funds for the Central Universities,Nankai University.
文摘Chlorinated antibiotics pose great challenges in efficient removal,while for the first time,this work greatly enhanced their electrocatalytic dechlorination performance by construction of non-noble metal Co_(3)O_(4)/g-C_(3)N_(4) heterojunctions to improve process cost-effectiveness.The Co_(3)O_(4)/g-C_(3)N_(4) heterojunction demonstrated an effective removal of 93.6%thiamphenicol(TAP)within 45 min,with the rate constant(0.0584 min^(-1))that was 2.4 and 2.8 times that of Co_(3)O_(4) and g-C_(3)N_(4) alone,respectively.The formation of heterojunctions facilitated electron transfer,enriched the electron density on Co_(3)O_(4),and enhanced the adsorption of pollutants as well as the desorption of degradation intermediates.The enhanced production of atomic hydrogen(H*)of Co_(3)O_(4)/g-C_(3)N_(4),which increased by 13.6-28.2 times,contributed more to pollutant removal(64.0%),much higher than that of Co_(3)O_(4)(37.3%)and g-C_(3)N_(4)(6.1%).The energy barrier for H_(2) formation on Co_(3)O_(4)/g-C_(3)N_(4)(0.75 eV)was higher than that on Co_(3)O_(4)(-1.84 eV),supporting that it could stabilize H*and inhibit the formation of H_(2).The Co_(3)O_(4)/g-C_(3)N_(4) heterojunction exhibited stable performance with less impact by pH and co-existing ions,and posed effectiveness for the dechlorination of typical chlorinated antibiotics.This study offers an efficient and sustainable strategy for constructing heterojunctions to enhance the performance of non-noble metal catalysts in electrocatalytic dechlorination.
基金supported by the National Natural Science Foundation of China(Nos.52270165 and 51978537)the Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province。
文摘The persistence of chlorinated alkanes in aquatic environments poses significant health risks due to its biotoxicity and high volatility,which contributes to both water and air pollution.This study investigates the efficacy of carbon dioxide radical anion(CO_(2)·^(-))mediated advanced reduction processes(ARPs)for the reductive dechlorination of chlorinated alkanes using small molecular monocarboxylic acids(SMAs)under UV irradiation.The study focused on formic acid(HCOOH),acetic acid(CH_3COOH),and propionic acid(CH_3CH_(2)COOH)to generate CO_(2)·^(-),revealing that UV/HCOOH system exhibits a notably high chloroform(CF)degradation efficiency of 97.8%in 90 min.Kinetic studies indicated a linear relationship between the HCOOH concentrations and the observed reaction rate constants(k_(obs)),demonstrating that CO_(2)·^(-)production is crucial for CF degradation.Electron paramagnetic resonance spectroscopy identified CO_(2)·^(-)and hydroxyl radicals(HO·)as the active species,with the former playing a predominant role in CF degradation.The study also explored the influence of carbon chain length in SMAs on CF degradation,finding that longer chains decrease the degradation efficiency,potentially due to reduced UV activation.A higher reaction rate constant(k_(obs))under acidic conditions,with a marked decrease in efficiency as the pH exceeds 3.7,where HCOO^(-)becomes predominant.This study enhances our understanding of CO_(2)·^(-)mediated ARPs and explores potential applications in environmental remediation,providing insights into the pathways and mechanisms of CF degradation.The UV/SMAs systems offer advantages for practical applications,such as milder reaction conditions and higher efficiency compared to traditional methods.
基金supported by the Hong Kong Research Grant Council (grant number 16208914)
文摘The formation of disinfection by-products（DBPs） from the degradation of N,N-diethyl-3-methyl benzoyl amide（DEET） and ibuprofen（IBP） by the ultraviolet irradiation（UV）/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H_2O_2 process.The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H_2O_2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species U（RCS） and hydroxyl radicals（HO） in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50%after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine（TOCl）, respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H_2O_2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%–63% higher,Ulikely due to the generation of more DBP precursors from the attack of RCS, in addition to HO.
基金supported by the National Natural Science Foundation of China (No. 21377143, 21077123 and 20877090)
文摘Benzophenones （BPs） are a class of widely used UV filters, which have been frequently detected within multiple environmental matrices. Disinfection is a necessary process in water treatment processes. The transformation behaviors and toxicity changes of 14 BP-type UV filters during chlorination disinfection treatment were investigated in this study. A new index, the acute toxicity formation potential, was proposed to evaluate the toxicity changes and potential risks of BP-type UV filters during chlorination treatment. It was found that 13 of 14 BP-type UV filters exhibited toxicity decreases in the chlorination disinfection process, more or less, while one showed a toxicity increase. The toxicity changes were dependent on substitution effects, such that 2,4-di-hydroxylated or 3-hydroxylated BPs exhibited significant toxicity decreases after chlorination treatment due to the ready cleavage of the aromatic ring. Importantly, the acute toxicity changes could be duplicated in an ambient water matrix.
基金supported by the National Environmental Protection Public Welfare Science and Technology Research Program of China(No.201109013)the National Natural Science Foundation of China(No.41373094,51208199)+2 种基金the Shanghai Natural Science Funds(No.12ZR1408000)the China Postdoctoral Science Foundation(No.2013T60429)the China Scholarship Councilfor PhD program at East China University of ScienceTechnology
文摘Titanium dioxide （TiO2）, which is the widely used photo-catalyst, has been synthesized by simple hydrothermal solution containing tetrabntyl titanate and hydrofluoric acid. The synthesized product has been applied to photo-degradation in aqueous phase of chlorinated solvents, namely tetra- chloroethene （PCE）, tdchloroethene （TCE） and 1,1,l-trichloroethane （TCA）. The photo-degradation results revealed that the degradation of these harmful chemicals was better in UV/synthesized TiO2 system compared to UV/commerciai P25 system and UV only system. The photo-catalytic efficiency of the synthesized TiO2 was 1.4, 1.8 and 3.0 folds higher compared to the commercial P25 for TCA, TCE and PCE degradation, respectively. Moreover, using nitrobenzene （NB） as a probe of hydroxyl radical （.OH）, the degradation rate was better over UV/synthesized TiO2, suggesting the high concentration of .OH generated in UV/synthesized TiO2 system. In addition, .OH concentration was confirmed by the strong peak displayed in EPR analysis over U~/synthesized TiO2 system. The characterization result using XRD and TEM showed that the synthesized TiO2 was in anatase form and consisted of well-defined sheet-shaped structures having a rectangular outline with a thickness of 4 rim, side length of 50 nm and width of 33 nra and a surface 90.3 m^2/g. XPS analysis revealed that ≡Ti-F bond was formed on the surface of the synthesized TiO2. The above results on both photocatalytic activity and the surface analysis demonstrated the good applicability of the synthesized TiO2 nano-sheets for the remediation of chlorinated solvent contaminated groundwater.
基金supported by the Shanxi Scholarship Council of China(No.2023-054)the Applied Basic Research Project of Shanxi Province,China(No.20210302123121)the National Natural Science Foundation of China(No.52170045).
文摘During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this study,the impact of chlorination and UV modification on the physicochemical properties of polystyrene(PS)and polyvinyl chloride(PVC)were investigated,and the adsorption behavior of pefloxacin(PEF)before and after modificationwas examined.The effect of pH,ionic strength,dissolved organicmatter,heavymetal ions and other water environmental conditions on adsorption behavior was revealed.The results showed that PS had a higher adsorption capacity of PEF than PVC,and the modification increased the presence of O-containing functional groups in the MPs,thereby enhancing the adsorption capacity of both materials.Chlorination had a more significant impact on the physicochemical properties of MPs compared to UV irradiation within the same time period,leading to better adsorption performance of chlorination.The optimal pH for adsorption was found to be 6,and NaCl,sodium alginate and Cu2+would inhibit adsorption to varying degrees,among which the inhibition caused by pH was the strongest.Chlorination and UV modification would weaken the inhibitory effect of environmental factors on the adsorption of PEF by MPs.The main mechanisms of adsorption involved electrostatic interaction and hydrogen bonding.The study clarified the effects of modification on the physicochemical properties of MPs,providing reference for subsequent biotoxicity analysis and environmental protection studies.
基金supported by the National Natural Science Foundation of China (No.22076217)the Henan Academy of Sciences 2021 Science and Technology Open Cooperation Project (No.210901007)。
文摘Ultraviolet/persulfate (UV/PS) and Ultraviolet/hydrogen peroxide (UV/H_(2)O_(2)) have attracted much attention in recent years as advanced oxidation processes for water treatment.However,it is not all clear how these two methods affect the formation of cyanogen chloride(CNCl) in the subsequent water chlorination process.In this study,it was found that both UV/H_(2)O_(2)and UV/PS pre-oxidation promoted the formation of CNCl in six actual water samples collected from urban rivers.Glycine,uric acid,arginine and histidine were investigated as the model compounds to explore the effects of different methods on the production of CNCl.The results showed that compared with chlorination alone,pre-oxidation by UV/H_(2)O_(2)and UV/PS can reduce the production of CNCl for glycine and uric acid by up to 95%during post-chlorination process.However,they can greatly promote the formation of CNCl for arginine and histidine by up to 120-fold.In a more detailed investigation,pre-oxidation of histidine formed highly reactive intermediates to chlorine,leading to increased CNCl formation and chlorine consumption.The results showed that the precursors of CNCl was altered after pre-oxidation,and need to be re-evaluated.
基金financially supported by the National Natural Science Foundation of China(No.52204310)the Guizhou Provincial Key Laboratory of Coal Clean Utilization(No.[2020]2001)+5 种基金the China Postdoctoral Science Foundation(Nos.2020TQ0059 and 2020M570967)the Natural Science Foundation of Liaoning Province(No.2021–MS–083)the Fundamental Research Funds for the Central Universities,China(No.N2125010)the Open Project Program of Key Laboratory of Metallurgical Emission Reduction&Resources Recycling(Anhui University of Technology),Ministry of Education(No.JKF22–02)the Foundation of Liupanshui Normal University(No.LPSSYZDZK202205)the Key Laboratory for Anisotropy and Texture of Materials,Ministry of Education,China。
文摘With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic analysis of the chlorination roasting kinetics and proposes a new two-step chlorination roasting process that integrates thermodynamics for the recycling of LIB cathode materials.The activation energy for the chloride reaction was 88.41 kJ/mol according to thermogravimetric analysis–derivative thermogravimetry data obtained by using model-free,model-fitting,and Z(α)function(αis conversion rate).Results indicated that the reaction was dominated by the first-order(F1)model when the conversion rate was less than or equal to 0.5 and shifted to the second-order(F2)model when the conversion rate exceeded 0.5.Optimal conditions were determined by thoroughly investigating the effects of roasting temperature,roasting time,and the mass ratio of NH_(4)Cl to LiCoO_(2).Under the optimal conditions,namely 400℃,20 min,and NH_(4)Cl/LiCoO_(2)mass ratio of 3:1,the leaching efficiency of Li and Co reached 99.43% and 99.05%,respectively.Analysis of the roasted products revealed that valuable metals in LiCoO_(2)transformed into CoCl_(2) and LiCl.Furthermore,the reaction mechanism was elucidated,providing insights for the establishment of a novel low-temperature chlorination roasting technology based on a crystal structure perspective.This technology can guide the development of LIB recycling processes with low energy consumption,low secondary pollution,high recovery efficiency,and high added value.
基金supported by the National Natural Science Foundation of China(Nos.21577154,21377143)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14040201)
文摘Benzophenones（BPs）, a group of widely used UV filters, exert multiple, significant toxicity effects. The 11 BPs were selected as target compounds, and the photobacterium acute toxicity test and an index for acute toxicity formation potential（ATFP） were used to evaluate the toxicity variation of BPs before and after a photoinduction–chlorination disinfection process.Orthogonal experiments were performed at different pH values and chlorine dosages. The characteristics of ATFP values for 11 BPs after a photoinduction–chlorination process can be summarized as follows：（1） The ATFPs decreased as the hydroxyl group number increased in BPs molecules.（2） For those BPs with the same hydroxyl group number, the ATFPs were higher when the hydroxyl groups were located at the 3-or 4-position than those at the 2-position; the BPs with hydroxyl groups distributed on two benzene rings had higher ATFPs than those on one ring.（3） Introducing a methoxyl group and sulfonic acid group into BP molecules increased the ATFP values.（4） The ATFPs were p H-dependent, the values of which were lowest at the neutral condition and highest at the acid condition.（5） The ATFPs increased and then decreased as the chlorine dosage increased. The results can be used as a reference to scientifically evaluate the environmental fate and potential risk of BPs in photoinduction–chlorination disinfection processes.
基金support from the National Natural Science Foundation of China(Nos.52373176,52073067)。
文摘Benzotriazole(BTA)-based A_(2)-A_1-D-A_1-A_(2)type wide-bandgap(WBG)non-fullerene acceptors(NFAs)have shown promising potential in indoor photovoltaic,and in-depth investigation of their structure-property relationship is of great significance.Herein,we explored the chlorination effect of the side chain on the terminals.We introduced Cl atoms into the benzyl side chains in parent BTA5 to synthesize two NFAs,BTA5-Cl with mono-chlorinated benzyl groups and BTA5-2Cl containing bi-chlorinated benzyl groups.We chose D18-Cl with deep-energy levels and strong crystallinity to pair with these three acceptors,affording high photovoltage and photocurrent.With the stepwise chlorination,the open-circuit voltage(V_(OC))values decrease from 1.28,1.22,to 1.20 V,while the corresponding power conversion efficiencies(PCEs)improve from 5.07%,9.15%,to 10.96%.Compared with BTA5-based OSCs,introducing Cl atoms downshifts the energy levels and slightly increases the non-radiative energy loss(0.14<0.17<0.19 e V),resulting in a sequential decrease in VO C.However,more chlorine atom replacements produce more effective exciton dissociation,higher charge transfer,and balanced carrier mobility in the blend films,ultimately achieving better PCEs.This work indicates that chlorination of the benzyl group on the terminals can improve the device's performance,implying good application potential in indoor photovoltaics.
基金Project supported by the National Natural Science Foundation of China(52261037,52401251)Key Research Project of Jiangxi Province(20203ABC28W006)+2 种基金the Research Fund of Key Laboratory of Rare Earths,Chinese Academy of SciencesKey Laboratory of Ionic Rare Earth Re sources and Environment,Ministry of Natural Resources of the People's Republic of China(2022IRERE302)the Ganzhou Science and Technology Innovation Empowerment Youth"Jie bang Gua shuai"Project。
文摘Recovery of rare earth elements(REEs)from bulk Nd-Fe-B scrap by chlorination with NH_(4)Cl as a chlorinating agent has been reported to be an energy efficient and environmentally friendly method.However,the reaction mechanism and phase evolution of the low-temperature selective chlorination process of Nd-Fe-B sludge are not clear.In this paper,we systematically investigated the lowtemperature selective chlorination process of Nd-Fe-B sludge with NH4Cl by combining thermokinetic theoretical calculations and experiments,and revealed its reaction mechanism.The phase evolution during chlorination was determined by X-ray diffraction(XRD),scanning electron microscopy(SEM)and ene rgy-dispersive X-ray spectroscopy(EDS)characterization as well as co mputational analysis of the phase stability diagram of the M-O-Cl system.To determine the optimum chlorination conditions,the effects of chlorinating agent dosage,reaction temperature and reaction time on the reaction were investigated.The results show that the rare earth components in Nd-Fe-B sludge are selectively chlorinated to RECl3and the formation of REOCl is avoided in the temperature range of 300-420℃,while the iron components are preferentially oxidized to Fe2O3.The selective chlorination reaction is consistent with the unreacted shrinking core model,and the rate-controlling step of the reaction is the internal diffusion process of NH4Cl through the transition layer of the reactant product to the surface of the Nd-Fe-B sludge.The complete chlorination of REEs is successfully achieved and 99.8%of REEs are selectively extracted into the leaching solution under optimal chlorination conditions(300℃,2.5 times of stoichiometric amount,4 h).
基金Project supported by China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202121)Jiangxi Provincial Key Laboratory of Flash Green Development and Recycling(20193BCD40019)+1 种基金Academic and Technical Leaders of Major Disciplines in Jiangxi Province(20213BCJ22003)Yichun Science and Technology Plan Project(2023YBKJGG04)。
文摘Due to the lack of effective screening systems in the rare earth waste recycling industry,the composition of rare earth elements in rare earth waste is complex and difficult to separate.In response to such problems,by studying the reaction behavior between various elements in rare earth waste and cobalt chloride,we propose a process path for the separation and recovery of iron,cerium and other rare earth elements using cobalt chloride roasting.The experiments on simulated wastes show that the leaching rates of the Nd,Sm,Gd,Pr can reach 98.31%,94.5%,93.87%and 72.05%under the optimal process conditions,respectively.Ce and iron remain in the leaching residue in the form of CeO_(2)and CoFe_(2)O_(4),respectively.And through a simple magnetic separation process,CeO_(2)and CoFe_(2)O_(4)can be enriched in non-magnetic leaching residue and magnetic leaching residue,respectively.The cerium content in the leaching residue composed of cobalt ferrite is only 1.95%.Therefore,this method is beneficial to the separation and high-value utilization of iron,cerium,and other rare earth elements in the waste system.The research results can provide theoretical reference for the low-cost and high-value recovery of rare earth secondary resources.
