Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advan...Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advanced oxidation processes(AOPs)are adopted to remove the antibiotic of sul-fachloropyridazine(SCP).Nanosized Mn_(2)O_(3) was fabricated on the SBA-15 material to catalytically acti-vate potassium peroxydisulfate(PDS)to generate reactive oxygen radicals of.OH and SO_(4).for SCP degradation.The effects of location and size of Mn_(2)O_(3) were explored through choosing either the as-made or template free SBA-15 as the precursor of substrate.Great influences from the site and size of Mn_(2)O_(3) on the oxidation activity were discovered.It was found that Mn_(2)O_(3) with a large size at the exterior of SBA-15(Mn-tfSBA)was slightly easier to degrade SCP at a low manganese loading of 1.0-2.0 mmol.g;however,complete SCP removal could only be achieved on the catalyst of Mn_(2)O_(3) with a refined size at the interior of SBA-15(Mn-asSBA).Moreover,the SO_(4).species were revealed to be the decisive radicals in the SCP degradation processes.Exploring the as-made mesoporous silica as a support provides a new idea for the further development of environmentally friendly catalysts.展开更多
Non-thermal plasma has emerged as an effective treatment system against the latest class of highly recalcitrant and toxic environmental pollutants termed emerging contaminants(ECs).In the present work,a detailed exper...Non-thermal plasma has emerged as an effective treatment system against the latest class of highly recalcitrant and toxic environmental pollutants termed emerging contaminants(ECs).In the present work,a detailed experimental study is carried out to evaluate the efficacy of a non-thermal plasma jet with two dyes,Rd.B and Met.Blue,as model contaminants.The plasma jet provided a complete dye decoloration in 30 min with an applied voltage of 6.5 kV_(p-p).·OH,having the highest oxidation potential,acts as the main reactive species,which with direct action on contaminants also acts indirectly by getting converted into H_(2)O_(2)and O_(3).Further,the effect of critical operational parameters viz,sample pH,applied voltage(4.5–6.5 kV_(p-p)),conductivity(5–20 mS cm^(-1)),and sample distance on plasma treatment efficacy was also examined.Out of all the assessed parameters,the applied voltage and sample conductivity was found to be the most significant operating parameters.A high voltage and low conductivity favored the dye decoloration,while the pH effect was not that significant.To understand the influence of plasma discharge gas on treatment efficacy,all the experiments are conducted with argon and helium gases under the fixed geometrical configuration.Both the gases provided a similar dye decoloration efficiency.The DBD plasma system with complete dye removal also rendered maximum mineralization of 73%for Rd.B,and 60%for Met.Blue.Finally,the system's efficiency against the actual ECs(four pharmaceutical compounds,viz,metformin,atenolol,acetaminophen,and ranitidine)and microbial contaminant(E.coli)was also tested.The system showed effectivity in the complete removal of targeted pharmaceuticals and a log2.5 E.coli reduction.The present systematic characterization of dye degradation could be of interest to large communities working towards commercializing plasma treatment systems.展开更多
The ubiquity of micropollutants(MPs)in aquatic environments has attracted increasing concern for public health and ecological security.Compared to conventional biological treatment,photocatalytic processes show more e...The ubiquity of micropollutants(MPs)in aquatic environments has attracted increasing concern for public health and ecological security.Compared to conventional biological treatment,photocatalytic processes show more efficiency in degrading MPs,but they require expensive materials and complicated synthesis processes.This study developed an economic photocatalytic process to degrade micropollutants.We synthesized urea-based graphitic carbon nitride(g-C_(3)N_(4))by a facile one-step pyrolysis method and evaluated the photocatalytic efficiency of carbamazepine(CBZ).Under simulated solar irradiation,g-C_(3)N_(4) could achieve 100% removal efficiency of 0.1 mg/L CBZ in spiked wastewater effluent within 15 min,and 86.5% removal efficiency in wastewater influent after 20 min of irradiation.The porous structure of g-C_(3)N_(4) promoted effective charge separation and mass transport of CBZ near the catalyst surface,enabling a high kinetic rate(0.3662 min^(-1)).Reactive oxygen species trapping experiments revealed that superoxide radicals(O_(2)^(·-))and holes(h^(+))were the major active radicals.Electron paramagnetic resonance(EPR)further confirmed the presence of O_(2)^(·-),·OH,^(1)O_(2) and holes.The pH,light intensity and initial CBZ concentration were found to have significant impacts on the removal efficiency of CBZ.Possible reaction intermediates were identified and the degradation pathway was proposed.Multiple MPs were selected to further demonstrate photocatalytic efficiency of g-C_(3)N_(4).The facile synthesis,superior efficiency,and versatility of g-C_(3)N_(4) make it a promising catalyst for application in tertiary wastewater treatment processes.展开更多
Cobalt iron spinel(CoFe_(2)O_(4)) has been considered as a good heterogeneous catalysis to peroxymonosulfate(PMS) in the degradation of persistent organic pollutants due to its magnetic properties and good chemical st...Cobalt iron spinel(CoFe_(2)O_(4)) has been considered as a good heterogeneous catalysis to peroxymonosulfate(PMS) in the degradation of persistent organic pollutants due to its magnetic properties and good chemical stability. However, its catalytic activity needs to be further improved. Here, a facial strategy, “in-situ substitution”, was adopted to modify CoFe_(2)O_(4) to improve its catalytic performance just by suitably increasing the Co/Fe ratio in synthesis process. Compared with CoFe_(2)O_(4), the newly synthesized Co_(1.5)Fe_(1.5)O_(4), could not only significantly improve the degradation efficiency of phenol, from 50.69 to 93.6%, but also exhibited more effective mineralization ability and higher PMS utilization. The activation energy advantage for phenol degradation using Co_(1.5)Fe_(1.5)O_(4)was only 44.2 k J/mol, much lower than that with CoFe_(2)O_(4)(127.3 k J/mol). A series of related representations of CoFe_(2)O_(4) and Co_(1.5)Fe_(1.5)O_(4) were compared to explore the possible reasons for the outstanding catalytic activity of Co_(1.5)Fe_(1.5)O_(4). Results showed that Co_(1.5)Fe_(1.5)O_(4)as well represented spinel crystal as CoFe_(2)O_(4)and the excess cobalt just partially replaced the position of iron without changing the original structure. Co_(1.5)Fe_(1.5)O_(4) had smaller particle size(8.7 nm), larger specific surface area(126.3 m^(2)/g), which was more favorable for exposure of active sites. Apart from the superior physical properties, more importantly, more reactive centers Co(Ⅱ) and surface hydroxyl compounds generated on Co_(1.5)Fe_(1.5)O_(4), which might be the major reason. Furthermore, Co_(1.5)Fe_(1.5)O_(4) behaved good paramagnetism, wide range of pH suitability and strong resistance to salt interference, making it a new prospect in environmental application.展开更多
In the present work we compared the biological activity of DCF,4’-OHDCF and 5-OHDCF as molecules of most biodegradation pathways of DCF and selected transformation products(2-hydroxyphenylacetic acid;2,5-dihydroxyphe...In the present work we compared the biological activity of DCF,4’-OHDCF and 5-OHDCF as molecules of most biodegradation pathways of DCF and selected transformation products(2-hydroxyphenylacetic acid;2,5-dihydroxyphenylacetic acid and 2,6-dichloroaniline)which are produced during AOPs,such as ozonation and UV/H2 O2.We also examined the interaction of DCF with chlorogenic acid(CGA).CGA is commonly used in human diet and entering the environment along with waste mainly from the processing and brewing of coffee and it can be toxic for microorganisms included in activated sludge.In the present experiment the evaluation of following parameters was performed:E.coli K-12 cells viability,growth inhibition of E.coli K-12 culture,LC50 and mortality of Chironomus aprilinus,ge no toxicity,sodA promoter induction and ROS generation.In addition the reactivity of E.coli SM recA:luxCDABE biosensor strain in wastewater matrices was measured.The results showed the influence of DCF,4’-OHDCF and 5-OHDCF on E.coli K-12 cells viability and bacteria growth,comparable to AOPs by-products.The highest toxicity was observed for selected,tested AOPs by-products,in comparison to the DCF,4’-OHDCF and 5-OHDCF.Genotoxicity assay indicated that 2,6-dichloroaniline(AOPs by-product)had the highest toxic effect.The oxidative stress assays revealed that the highest level of ROS generation and sodA promoter induction were obtained for DCF,4’-OHDCF and 5-OHDCF,compared to other tested compounds.We have also found that there is an interaction between chlorogenic acid and DCF,which resulted in increased toxicity of the mixture of the both compounds to E.coli K-12,comparable to parent chemicals.The strongest response of E.coli SM biosensor strain with recA:luxCDABE genetic construct in filtered treated wastewaters,comparable to control sample was noticed.It indicates,that E.coli SM recA:luxCDABE biosensor strains is a good tool for bacteria monitoring in wastewater environment.Due to toxicity and biological activity of tested DCF transformation products,there is a need to use additional wastewater treatment systems for wastewater contaminated with pharmaceutical residues.展开更多
基金funding support from National Natural Science Foundation of China (51602133)State Key Laboratory of Materials-Oriented Chemical Engineering (KL19-05)
文摘Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advanced oxidation processes(AOPs)are adopted to remove the antibiotic of sul-fachloropyridazine(SCP).Nanosized Mn_(2)O_(3) was fabricated on the SBA-15 material to catalytically acti-vate potassium peroxydisulfate(PDS)to generate reactive oxygen radicals of.OH and SO_(4).for SCP degradation.The effects of location and size of Mn_(2)O_(3) were explored through choosing either the as-made or template free SBA-15 as the precursor of substrate.Great influences from the site and size of Mn_(2)O_(3) on the oxidation activity were discovered.It was found that Mn_(2)O_(3) with a large size at the exterior of SBA-15(Mn-tfSBA)was slightly easier to degrade SCP at a low manganese loading of 1.0-2.0 mmol.g;however,complete SCP removal could only be achieved on the catalyst of Mn_(2)O_(3) with a refined size at the interior of SBA-15(Mn-asSBA).Moreover,the SO_(4).species were revealed to be the decisive radicals in the SCP degradation processes.Exploring the as-made mesoporous silica as a support provides a new idea for the further development of environmentally friendly catalysts.
基金supported by grants from the IIT Delhi FIRP program grant (No. MI02081)
文摘Non-thermal plasma has emerged as an effective treatment system against the latest class of highly recalcitrant and toxic environmental pollutants termed emerging contaminants(ECs).In the present work,a detailed experimental study is carried out to evaluate the efficacy of a non-thermal plasma jet with two dyes,Rd.B and Met.Blue,as model contaminants.The plasma jet provided a complete dye decoloration in 30 min with an applied voltage of 6.5 kV_(p-p).·OH,having the highest oxidation potential,acts as the main reactive species,which with direct action on contaminants also acts indirectly by getting converted into H_(2)O_(2)and O_(3).Further,the effect of critical operational parameters viz,sample pH,applied voltage(4.5–6.5 kV_(p-p)),conductivity(5–20 mS cm^(-1)),and sample distance on plasma treatment efficacy was also examined.Out of all the assessed parameters,the applied voltage and sample conductivity was found to be the most significant operating parameters.A high voltage and low conductivity favored the dye decoloration,while the pH effect was not that significant.To understand the influence of plasma discharge gas on treatment efficacy,all the experiments are conducted with argon and helium gases under the fixed geometrical configuration.Both the gases provided a similar dye decoloration efficiency.The DBD plasma system with complete dye removal also rendered maximum mineralization of 73%for Rd.B,and 60%for Met.Blue.Finally,the system's efficiency against the actual ECs(four pharmaceutical compounds,viz,metformin,atenolol,acetaminophen,and ranitidine)and microbial contaminant(E.coli)was also tested.The system showed effectivity in the complete removal of targeted pharmaceuticals and a log2.5 E.coli reduction.The present systematic characterization of dye degradation could be of interest to large communities working towards commercializing plasma treatment systems.
基金supported by the National Natural Science Foundation of China(41977085)the Qing Lan Project,the 333 Project of Jiangsu Province(BRA202030)+4 种基金the Six Talent Peaks Project in Jiangsu Province(2018-TD-JNHB-012)the Lvyang Jinfeng Fund of Yangzhou(137012724)the Research Foundation of Yangzhou University(137012446)Doctor of Mass Entrepreneurship and Innovation of Jiangsu Province(337090323)the Innovation Fostering Fund of Yangzhou University.
基金funding support through the project DP 170104330the support by Australian Research Council Future Fellowship(FT170100196).
文摘The ubiquity of micropollutants(MPs)in aquatic environments has attracted increasing concern for public health and ecological security.Compared to conventional biological treatment,photocatalytic processes show more efficiency in degrading MPs,but they require expensive materials and complicated synthesis processes.This study developed an economic photocatalytic process to degrade micropollutants.We synthesized urea-based graphitic carbon nitride(g-C_(3)N_(4))by a facile one-step pyrolysis method and evaluated the photocatalytic efficiency of carbamazepine(CBZ).Under simulated solar irradiation,g-C_(3)N_(4) could achieve 100% removal efficiency of 0.1 mg/L CBZ in spiked wastewater effluent within 15 min,and 86.5% removal efficiency in wastewater influent after 20 min of irradiation.The porous structure of g-C_(3)N_(4) promoted effective charge separation and mass transport of CBZ near the catalyst surface,enabling a high kinetic rate(0.3662 min^(-1)).Reactive oxygen species trapping experiments revealed that superoxide radicals(O_(2)^(·-))and holes(h^(+))were the major active radicals.Electron paramagnetic resonance(EPR)further confirmed the presence of O_(2)^(·-),·OH,^(1)O_(2) and holes.The pH,light intensity and initial CBZ concentration were found to have significant impacts on the removal efficiency of CBZ.Possible reaction intermediates were identified and the degradation pathway was proposed.Multiple MPs were selected to further demonstrate photocatalytic efficiency of g-C_(3)N_(4).The facile synthesis,superior efficiency,and versatility of g-C_(3)N_(4) make it a promising catalyst for application in tertiary wastewater treatment processes.
基金financially supported by the Key Research and Development(R&D)Projects of Shanxi Province(No.201803D31050)。
文摘Cobalt iron spinel(CoFe_(2)O_(4)) has been considered as a good heterogeneous catalysis to peroxymonosulfate(PMS) in the degradation of persistent organic pollutants due to its magnetic properties and good chemical stability. However, its catalytic activity needs to be further improved. Here, a facial strategy, “in-situ substitution”, was adopted to modify CoFe_(2)O_(4) to improve its catalytic performance just by suitably increasing the Co/Fe ratio in synthesis process. Compared with CoFe_(2)O_(4), the newly synthesized Co_(1.5)Fe_(1.5)O_(4), could not only significantly improve the degradation efficiency of phenol, from 50.69 to 93.6%, but also exhibited more effective mineralization ability and higher PMS utilization. The activation energy advantage for phenol degradation using Co_(1.5)Fe_(1.5)O_(4)was only 44.2 k J/mol, much lower than that with CoFe_(2)O_(4)(127.3 k J/mol). A series of related representations of CoFe_(2)O_(4) and Co_(1.5)Fe_(1.5)O_(4) were compared to explore the possible reasons for the outstanding catalytic activity of Co_(1.5)Fe_(1.5)O_(4). Results showed that Co_(1.5)Fe_(1.5)O_(4)as well represented spinel crystal as CoFe_(2)O_(4)and the excess cobalt just partially replaced the position of iron without changing the original structure. Co_(1.5)Fe_(1.5)O_(4) had smaller particle size(8.7 nm), larger specific surface area(126.3 m^(2)/g), which was more favorable for exposure of active sites. Apart from the superior physical properties, more importantly, more reactive centers Co(Ⅱ) and surface hydroxyl compounds generated on Co_(1.5)Fe_(1.5)O_(4), which might be the major reason. Furthermore, Co_(1.5)Fe_(1.5)O_(4) behaved good paramagnetism, wide range of pH suitability and strong resistance to salt interference, making it a new prospect in environmental application.
基金financially supported by National Science Centre,Poland,under the research project number 2018/29/B/NZ9/01997
文摘In the present work we compared the biological activity of DCF,4’-OHDCF and 5-OHDCF as molecules of most biodegradation pathways of DCF and selected transformation products(2-hydroxyphenylacetic acid;2,5-dihydroxyphenylacetic acid and 2,6-dichloroaniline)which are produced during AOPs,such as ozonation and UV/H2 O2.We also examined the interaction of DCF with chlorogenic acid(CGA).CGA is commonly used in human diet and entering the environment along with waste mainly from the processing and brewing of coffee and it can be toxic for microorganisms included in activated sludge.In the present experiment the evaluation of following parameters was performed:E.coli K-12 cells viability,growth inhibition of E.coli K-12 culture,LC50 and mortality of Chironomus aprilinus,ge no toxicity,sodA promoter induction and ROS generation.In addition the reactivity of E.coli SM recA:luxCDABE biosensor strain in wastewater matrices was measured.The results showed the influence of DCF,4’-OHDCF and 5-OHDCF on E.coli K-12 cells viability and bacteria growth,comparable to AOPs by-products.The highest toxicity was observed for selected,tested AOPs by-products,in comparison to the DCF,4’-OHDCF and 5-OHDCF.Genotoxicity assay indicated that 2,6-dichloroaniline(AOPs by-product)had the highest toxic effect.The oxidative stress assays revealed that the highest level of ROS generation and sodA promoter induction were obtained for DCF,4’-OHDCF and 5-OHDCF,compared to other tested compounds.We have also found that there is an interaction between chlorogenic acid and DCF,which resulted in increased toxicity of the mixture of the both compounds to E.coli K-12,comparable to parent chemicals.The strongest response of E.coli SM biosensor strain with recA:luxCDABE genetic construct in filtered treated wastewaters,comparable to control sample was noticed.It indicates,that E.coli SM recA:luxCDABE biosensor strains is a good tool for bacteria monitoring in wastewater environment.Due to toxicity and biological activity of tested DCF transformation products,there is a need to use additional wastewater treatment systems for wastewater contaminated with pharmaceutical residues.
