Antibiotic resistant bacteria(ARB)with antibiotic resistance genes(ARGs)can reduce or eliminate the effectiveness of antibiotics and thus threaten human health.The United Nations Environment Programme considers antibi...Antibiotic resistant bacteria(ARB)with antibiotic resistance genes(ARGs)can reduce or eliminate the effectiveness of antibiotics and thus threaten human health.The United Nations Environment Programme considers antibiotic resistance the first of six emerging issues of concern.Advanced oxidation processes(AOPs)that combine ultraviolet(UV)irradiation and chemical oxidation(primarily chlorine,hydrogen peroxide,and persulfate)have attracted increasing interest as advanced water and wastewater treatment technologies.These integrated technologies have been reported to significantly elevate the efficiencies of ARB inactivation and ARG degradation compared with direct UV irradiation or chemical oxidation alone due to the generation of multiple reactive species.In this study,the performance and underlying mechanisms of UV/chlorine,UV/hydrogen peroxide,and UV/persulfate processes for controlling ARB and ARGs were reviewed based on recent studies.Factors affecting the process-specific efficiency in controlling ARB and ARGs were discussed,including biotic factors,oxidant dose,UV fluence,pH,and water matrix properties.In addition,the cost-effectiveness of the UV-based AOPs was evaluated using the concept of electrical energy per order.The UV/chlorine process exhibited a higher efficiency with lower energy consumption than other UV-based AOPs in the wastewater matrix,indicating its potential for ARB inactivation and ARG degradation in wastewater treatment.Further studies are required to address the trade-off between toxic byproduct formation and the energy efficiency of the UV/chlorine process in real wastewater to facilitate its optimization and application in the control of ARB and ARGs.展开更多
Azo dyes are commonly found as pollutants in wastewater from the textile industry,and can cause environmental problems because of their color and toxicity.The removal of a typical azo dye named C.I.Reactive Red 2（RR2...Azo dyes are commonly found as pollutants in wastewater from the textile industry,and can cause environmental problems because of their color and toxicity.The removal of a typical azo dye named C.I.Reactive Red 2（RR2） during low pressure ultraviolet（UV）/chlorine oxidation was investigated in this study.UV irradiation at 254 nm and addition of free chlorine provided much higher removal rates of RR2 and color than UV irradiation or chlorination alone.Increasing the free chlorine dose enhanced the removal efficiency of RR2 and color by UV/chlorine oxidation.Experiments performed with nitrobenzene（NB）or benzoic acid（BA） as scavengers showed that radicals（especially OH） formed during UV/chlorine oxidation are important in the RR2 removal.Addition of HCO_3^- and Cl^- to the RR2 solution did not inhibit the removal of RR2 during UV/chlorine oxidation.展开更多
Drinking water utilities are interested in upgrading their treatment facilities to enhance micropollutant removal and byproduct control.Pre-oxidation by chlorine dioxide(ClO_(2))followed by coagulation-flocculation-se...Drinking water utilities are interested in upgrading their treatment facilities to enhance micropollutant removal and byproduct control.Pre-oxidation by chlorine dioxide(ClO_(2))followed by coagulation-flocculation-sedimentation and advanced oxidation processes(AOPs)is one of the promising solutions.However,the chlorite(ClO_(2)^(-))formed from the ClO_(2) preoxidation stage cannot be removed by the conventional coagulation process using aluminum sulfate.ClO_(2)^(–)negatively affects the post-UV/chlorine process due to its strong radical scavenging effect,and it also enhances the formation of chlorate(ClO_(3)^(–)).In this study,dosing micromolar-level ferrous iron(Fe(II))into aluminum-based coagulants was proposed to eliminate the ClO_(2)^(–)generated from ClO_(2) pre-oxidation and benefit the post-UV/chlorine process in radical production and ClO_(3)^(–)reduction.Results showed that the addition of 52.1-μmol/L FeSO_(4) effectively eliminated the ClO_(2)^(-)generated from the pre-oxidation using 1.0 mg/L(14.8μmol/L)of ClO 2.Reduction of ClO_(2)^(-)increased the degradation rate constant of a model micropollutant(carbamazepine)by 55.0%in the post-UV/chlorine process.The enhanced degradation was verified to be attributed to the increased steady-state concentrations of HO^(-)·and ClO_(2)·by Fe(II)addition.Moreover,Fe(II)addition also decreased the ClO_(3)^(–)formation by 53.8%in the UV/chlorine process and its impact on the formation of chloroorganic byproducts was rather minor.The findings demonstrated a promising strategy to improve the drinking water quality and safety by adding low-level Fe(II)in coagulation in an advanced drinking water treatment train.展开更多
Fe-based metallic glasses (Fe–MGs) are potential candidate catalysts for advanced oxidation processes(AOPs) for recalcitrant organic pollutant degradation. However, industrial wastewater and natural contaminated site...Fe-based metallic glasses (Fe–MGs) are potential candidate catalysts for advanced oxidation processes(AOPs) for recalcitrant organic pollutant degradation. However, industrial wastewater and natural contaminated sites usually contain abundant inorganic ions, like the chloride ion (Cl−), which significantly affectAOPs, but their influence on MG-activated AOPs still remains unclear. Through the study of three commonly used oxidants, hydrogen peroxide (H_(2)O_(2)), peroxydisulfate (PDS), and peroxymonosulfate (PMS), theeffect of Cl− on the FeSiB-catalyzed process of degradation of the typical azo dye Orange Ⅱ was investigated. Evidence indicates that the addition of Cl− resulted in the monotonous inhibition of the degradation process when the H_(2)O_(2)/FeSiB and PDS/FeSiB systems were employed, but promoted effect wasdetected with the PMS/FeSiB system, which is different from the previously observed dual effect of Cl−.It is closely relative with FeSiB induced unique variety of degradation pathways, including radicals, nonradicals (^(1)O_(2)), and direct reduction degradation. Moreover, the presence of Cl− significantly affected thesystems’ absorbable organic halogen content and the amount of Fe leached into the solution. The resultsof this work will provide essential references for Fe-based MG used as AOP catalysts in field applicationsand the development of advanced MGs with excellent adaptability to complex environments.展开更多
基金supported by grants from the Research Grants Council of the Hong Kong SAR,China(T21-705/20-N and 16210221).
文摘Antibiotic resistant bacteria(ARB)with antibiotic resistance genes(ARGs)can reduce or eliminate the effectiveness of antibiotics and thus threaten human health.The United Nations Environment Programme considers antibiotic resistance the first of six emerging issues of concern.Advanced oxidation processes(AOPs)that combine ultraviolet(UV)irradiation and chemical oxidation(primarily chlorine,hydrogen peroxide,and persulfate)have attracted increasing interest as advanced water and wastewater treatment technologies.These integrated technologies have been reported to significantly elevate the efficiencies of ARB inactivation and ARG degradation compared with direct UV irradiation or chemical oxidation alone due to the generation of multiple reactive species.In this study,the performance and underlying mechanisms of UV/chlorine,UV/hydrogen peroxide,and UV/persulfate processes for controlling ARB and ARGs were reviewed based on recent studies.Factors affecting the process-specific efficiency in controlling ARB and ARGs were discussed,including biotic factors,oxidant dose,UV fluence,pH,and water matrix properties.In addition,the cost-effectiveness of the UV-based AOPs was evaluated using the concept of electrical energy per order.The UV/chlorine process exhibited a higher efficiency with lower energy consumption than other UV-based AOPs in the wastewater matrix,indicating its potential for ARB inactivation and ARG degradation in wastewater treatment.Further studies are required to address the trade-off between toxic byproduct formation and the energy efficiency of the UV/chlorine process in real wastewater to facilitate its optimization and application in the control of ARB and ARGs.
基金funded by the National High-tech R&D Program(863)of China(No.2013AA065205)the Shenzhen Science and Technology Innovation Commission(No.JSGG20140703145428318)the National Science Fund of China(No.51138006)
文摘Azo dyes are commonly found as pollutants in wastewater from the textile industry,and can cause environmental problems because of their color and toxicity.The removal of a typical azo dye named C.I.Reactive Red 2（RR2） during low pressure ultraviolet（UV）/chlorine oxidation was investigated in this study.UV irradiation at 254 nm and addition of free chlorine provided much higher removal rates of RR2 and color than UV irradiation or chlorination alone.Increasing the free chlorine dose enhanced the removal efficiency of RR2 and color by UV/chlorine oxidation.Experiments performed with nitrobenzene（NB）or benzoic acid（BA） as scavengers showed that radicals（especially OH） formed during UV/chlorine oxidation are important in the RR2 removal.Addition of HCO_3^- and Cl^- to the RR2 solution did not inhibit the removal of RR2 during UV/chlorine oxidation.
基金supported by the Hong Kong Innovation and Technology Fund (No. GHP/010/18GD)the National Natural Science Foundation of China (No. 21876210)+1 种基金the Hong Kong Research Grants Council (No. T21-604/19-R)partially supported by a fellowship award from the Research Grants Council of the Hong Kong Special Administrative Region, China (No. HKUST PDFS2021-6S05)。
文摘Drinking water utilities are interested in upgrading their treatment facilities to enhance micropollutant removal and byproduct control.Pre-oxidation by chlorine dioxide(ClO_(2))followed by coagulation-flocculation-sedimentation and advanced oxidation processes(AOPs)is one of the promising solutions.However,the chlorite(ClO_(2)^(-))formed from the ClO_(2) preoxidation stage cannot be removed by the conventional coagulation process using aluminum sulfate.ClO_(2)^(–)negatively affects the post-UV/chlorine process due to its strong radical scavenging effect,and it also enhances the formation of chlorate(ClO_(3)^(–)).In this study,dosing micromolar-level ferrous iron(Fe(II))into aluminum-based coagulants was proposed to eliminate the ClO_(2)^(–)generated from ClO_(2) pre-oxidation and benefit the post-UV/chlorine process in radical production and ClO_(3)^(–)reduction.Results showed that the addition of 52.1-μmol/L FeSO_(4) effectively eliminated the ClO_(2)^(-)generated from the pre-oxidation using 1.0 mg/L(14.8μmol/L)of ClO 2.Reduction of ClO_(2)^(-)increased the degradation rate constant of a model micropollutant(carbamazepine)by 55.0%in the post-UV/chlorine process.The enhanced degradation was verified to be attributed to the increased steady-state concentrations of HO^(-)·and ClO_(2)·by Fe(II)addition.Moreover,Fe(II)addition also decreased the ClO_(3)^(–)formation by 53.8%in the UV/chlorine process and its impact on the formation of chloroorganic byproducts was rather minor.The findings demonstrated a promising strategy to improve the drinking water quality and safety by adding low-level Fe(II)in coagulation in an advanced drinking water treatment train.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52101195,51871120)the Natural Science Foundation of Jiangsu Province(Nos.BK20190480,BK20200019)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.30920021156,30920010004)the GuangdongHong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology。
文摘Fe-based metallic glasses (Fe–MGs) are potential candidate catalysts for advanced oxidation processes(AOPs) for recalcitrant organic pollutant degradation. However, industrial wastewater and natural contaminated sites usually contain abundant inorganic ions, like the chloride ion (Cl−), which significantly affectAOPs, but their influence on MG-activated AOPs still remains unclear. Through the study of three commonly used oxidants, hydrogen peroxide (H_(2)O_(2)), peroxydisulfate (PDS), and peroxymonosulfate (PMS), theeffect of Cl− on the FeSiB-catalyzed process of degradation of the typical azo dye Orange Ⅱ was investigated. Evidence indicates that the addition of Cl− resulted in the monotonous inhibition of the degradation process when the H_(2)O_(2)/FeSiB and PDS/FeSiB systems were employed, but promoted effect wasdetected with the PMS/FeSiB system, which is different from the previously observed dual effect of Cl−.It is closely relative with FeSiB induced unique variety of degradation pathways, including radicals, nonradicals (^(1)O_(2)), and direct reduction degradation. Moreover, the presence of Cl− significantly affected thesystems’ absorbable organic halogen content and the amount of Fe leached into the solution. The resultsof this work will provide essential references for Fe-based MG used as AOP catalysts in field applicationsand the development of advanced MGs with excellent adaptability to complex environments.
