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L. Zhou - One of the best experts on this subject based on the ideXlab platform.
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New insights into clopyralid degradation by Sulfate Radical: Pyridine ring cleavage pathways
Water Research, 2020Co-Authors: X. Yang, X. Ding, L. Zhou, H. Fan, X. Wang, C. Ferronato, J. Chovelon, G. XiuAbstract:Sulfate Radical
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New insights into clopyralid degradation by Sulfate Radical: Pyridine ring cleavage pathways.
Water Research, 2020Co-Authors: X. Yang, X. Ding, L. Zhou, X. Wang, C. Ferronato, J. Chovelon, Huan-huan Fan, G. XiuAbstract:Abstract Contamination by herbicides such as clopyralid (CLP) poses a significant threat to human health and ecological systems. In the present study, efficient removal of CLP was achieved by thermo activated perSulfate, among which Sulfate Radical was identified as the predominant oxidizing species responsible for the decontamination. Based on high resolution LC-MS, derivatization method and density functional theory (DFT) computation, the detailed oxidation pathways and mechanisms were proposed. The primary oxidation pathways included dechlorination-hydroxylation, decarboxylation and the formation of quinone-like moieties. Afterwards, numerous intermediate byproducts ranging from high molecular to very small ones were identified, suggesting the pyridine ring was damaged during the thermo activated perSulfate process. The detected products containing six and five carbons indicated the pyridine ring cleavage would take place on the quinone-structure intermediate. Further oxidation could continue by breaking each bond on the ring-cleavage product, yielding a series of short-chain carbonyl chemicals, carboxylic acids and inorganic ions. In addition, the presence of dissolved oxygen (DO) was favorable to CLP degradation, indicating DO played an important role in applying such technology. The degradation rate constants of CLP increased appreciably with increasing temperature, and acidic pH facilitated the CLP degradation. The results obtained in this work would increase our understanding on the environmental fates of nitrogen heterocyclic compounds during Sulfate Radical (SO4•−)-based advanced oxidation processes (SR-AOPs).
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Sulfate Radical mediated degradation of 5-halogenosalicylic acids: Phenoxyl Radical transformation pathways
Chemical Engineering Journal, 2020Co-Authors: L. Zhou, X. Yang, C. Ferronato, J. Chovelon, M. Sleiman, Qing Zhao, Claire RichardAbstract:Abstract In the present study, we investigated the degradation kinetics and transformation pathways of two 5-halogenosalicylic acids (5XSAs), namely, 5-chlorosalicylic acid (5ClSA) and 5-bromosalicylic acid (5BrSA) by Sulfate Radical (SO4•−) in a thermo-activated perSulfate system. The reaction pathways and mechanisms were proposed based on laser flash photolysis (LFP) techniques, HPLC-HRMS and molecular orbital calculations. Our results revealed that efficient removal of 5XSAs could be achieved by thermo-activated perSulfate, and phenoxyl Radicals were found to play key roles in the primary oxidation pathways. The subsequent transformation of phenoxyl Radicals included hydroxylation and coupling processes. The resulting coupling products could undergo secondary reactions with Sulfate Radical, including dehalogenation, decarboxylation and hydroxylation. Hydroxylated products were in turn oxidized by SO4•−, leading to the ring opening and the formation of a series of small molecular carbonyl byproducts. These processes could be responsible for the mineralization and the release of Br− or Cl−. In addition, the degradation rate constants of 5XSAs increased appreciably with increasing temperature, and higher efficiency of oxidation was observed around neutral initial pH. Moreover, degradation kinetics were found to be hardly affected by dissolved oxygen (DO), showing the possibility of applying SR-AOPs under environmental realistic conditions, not only for surface waters, but also for oxygen-deficient underground waters. The present work could increase our understanding on the reactivity and pathways of halogen phenols widely present in natural waters.
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Sulfate Radical induced degradation of β2 adrenoceptor agonists salbutamol and terbutaline implication of halides bicarbonate and natural organic matter
Chemical Engineering Journal, 2019Co-Authors: L. Zhou, X. Wang, C. Ferronato, J. Chovelon, M. Sleiman, Claire RichardAbstract:Abstract The presence of inorganic ions and organic matter in natural water would cause unpredictable consequence on the oxidation efficiency and pathways of Sulfate Radical (SO4 −) based advanced oxidation process (SR-AOPs). In this study, the impacts of water constituents, namely, halides (including chloride (Cl−) and bromide (Br−)), bicarbonate (HCO3−) and natural organic matter (NOM) on SO4 − induced degradation of salbutamol (SAL) and terbutaline (TBL) were evaluated systematically. Our results indicated that chloride exhibited no effect on oxidation efficiencies of SAL and TBL, while Br−, HCO3− and NOM all showed inhibitory effects. Specifically, the detrimental effect of bromide was mainly attributed to the scavenging of SO4 − to form the less reactive species, Br2 −. By using laser flash photolysis (LFP), the second-order rate constants of Br2 − with SAL and TBL were estimated to be 2.1 and 3.9 × 108 M−1 s−1, respectively, much smaller than those with SO4 − (3.7 × 109 M−1 s−1 for SAL and 4.2 × 109 M−1 s−1 for TBL). Moreover, bromine addition products of SAL and TBL were detected in the presence of Br−, which were believed to be more toxic than the parent compounds. Similar to bromide, HCO3− could also quench SO4 − to generate carbonate Radical (CO3 −), also less reactive than Sulfate Radical with SAL (4.8 × 107 M−1 s−1) and TBL (3.2 × 108 M−1 s−1). In the case of NOM, a light screening effect was regarded as the major factor responsible to the decrease of reaction rates, while Sulfate Radical scavenging played a very limited role. The present work would increase the awareness of secondary reactions during SR-AOPs, as more toxic products were generated in the case of bromide.
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rethinking Sulfate Radical based oxidation of nitrophenols formation of toxic polynitrophenols nitrated biphenyls and diphenyl ethers
Journal of Hazardous Materials, 2019Co-Authors: L. Zhou, C. Ferronato, Yan Yang, Lu Wang, Yuanyuan Shi, Peizeng Yang, Lei Zhou, J. ChovelonAbstract:Abstract Sulfate Radical (SO4 −)-based oxidation of nitrophenols (NPs) have been widely studied; however, formation of potentially more toxic polynitroaromatic intermediates has been overlooked. In this contribution, we systematically investigated the degradation of four NPs by a SO4 −-based oxidation process. Degradation efficiency of NPs followed the order: 2-nitrophenol (2-NP) > 4-nitrophenol (4-NP) > 2,4-dinitrophenol (2,4-DNP) > 2,6-dinitrophenol (2,6-DNP). HPLC and LC–MS/MS analysis confirmed the formation of 2,4-DNP, 2,6-DNP and 2,4,6-trinitrophenol (2,4,6-TNP) during NPs transformation by SO4 −, suggesting that both denitration and renitration processes occurred. Nitrogen dioxide Radicals (NO2 ) and phenoxy Radicals are responsible for the formation of polynitrophenols. Coupling products including nitrated biphenyls and diphenyl ethers were also detected, which were proposed to be formed by combinations of resonance-stabilized Radicals. Electron spin density and charge density calculation showed that ortho C-ortho C and ortho C-phenolic O were the most likely combination ways responsible for coupling products formation. ECOSAR program predicted that polynitrated diphenyl ethers and biphenyls had higher ecotoxicological effects on aquatic species such as fish and daphnia. Therefore, the formation of toxic polynitroaromatic intermediates in SO4 −-based advanced oxidation processes should be scrutinized before this technology can be safely utilized for water and wastewater treatment.
J. Chovelon - One of the best experts on this subject based on the ideXlab platform.
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New insights into clopyralid degradation by Sulfate Radical: Pyridine ring cleavage pathways
Water Research, 2020Co-Authors: X. Yang, X. Ding, L. Zhou, H. Fan, X. Wang, C. Ferronato, J. Chovelon, G. XiuAbstract:Sulfate Radical
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New insights into clopyralid degradation by Sulfate Radical: Pyridine ring cleavage pathways.
Water Research, 2020Co-Authors: X. Yang, X. Ding, L. Zhou, X. Wang, C. Ferronato, J. Chovelon, Huan-huan Fan, G. XiuAbstract:Abstract Contamination by herbicides such as clopyralid (CLP) poses a significant threat to human health and ecological systems. In the present study, efficient removal of CLP was achieved by thermo activated perSulfate, among which Sulfate Radical was identified as the predominant oxidizing species responsible for the decontamination. Based on high resolution LC-MS, derivatization method and density functional theory (DFT) computation, the detailed oxidation pathways and mechanisms were proposed. The primary oxidation pathways included dechlorination-hydroxylation, decarboxylation and the formation of quinone-like moieties. Afterwards, numerous intermediate byproducts ranging from high molecular to very small ones were identified, suggesting the pyridine ring was damaged during the thermo activated perSulfate process. The detected products containing six and five carbons indicated the pyridine ring cleavage would take place on the quinone-structure intermediate. Further oxidation could continue by breaking each bond on the ring-cleavage product, yielding a series of short-chain carbonyl chemicals, carboxylic acids and inorganic ions. In addition, the presence of dissolved oxygen (DO) was favorable to CLP degradation, indicating DO played an important role in applying such technology. The degradation rate constants of CLP increased appreciably with increasing temperature, and acidic pH facilitated the CLP degradation. The results obtained in this work would increase our understanding on the environmental fates of nitrogen heterocyclic compounds during Sulfate Radical (SO4•−)-based advanced oxidation processes (SR-AOPs).
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Sulfate Radical mediated degradation of 5-halogenosalicylic acids: Phenoxyl Radical transformation pathways
Chemical Engineering Journal, 2020Co-Authors: L. Zhou, X. Yang, C. Ferronato, J. Chovelon, M. Sleiman, Qing Zhao, Claire RichardAbstract:Abstract In the present study, we investigated the degradation kinetics and transformation pathways of two 5-halogenosalicylic acids (5XSAs), namely, 5-chlorosalicylic acid (5ClSA) and 5-bromosalicylic acid (5BrSA) by Sulfate Radical (SO4•−) in a thermo-activated perSulfate system. The reaction pathways and mechanisms were proposed based on laser flash photolysis (LFP) techniques, HPLC-HRMS and molecular orbital calculations. Our results revealed that efficient removal of 5XSAs could be achieved by thermo-activated perSulfate, and phenoxyl Radicals were found to play key roles in the primary oxidation pathways. The subsequent transformation of phenoxyl Radicals included hydroxylation and coupling processes. The resulting coupling products could undergo secondary reactions with Sulfate Radical, including dehalogenation, decarboxylation and hydroxylation. Hydroxylated products were in turn oxidized by SO4•−, leading to the ring opening and the formation of a series of small molecular carbonyl byproducts. These processes could be responsible for the mineralization and the release of Br− or Cl−. In addition, the degradation rate constants of 5XSAs increased appreciably with increasing temperature, and higher efficiency of oxidation was observed around neutral initial pH. Moreover, degradation kinetics were found to be hardly affected by dissolved oxygen (DO), showing the possibility of applying SR-AOPs under environmental realistic conditions, not only for surface waters, but also for oxygen-deficient underground waters. The present work could increase our understanding on the reactivity and pathways of halogen phenols widely present in natural waters.
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Sulfate Radical induced degradation of β2 adrenoceptor agonists salbutamol and terbutaline implication of halides bicarbonate and natural organic matter
Chemical Engineering Journal, 2019Co-Authors: L. Zhou, X. Wang, C. Ferronato, J. Chovelon, M. Sleiman, Claire RichardAbstract:Abstract The presence of inorganic ions and organic matter in natural water would cause unpredictable consequence on the oxidation efficiency and pathways of Sulfate Radical (SO4 −) based advanced oxidation process (SR-AOPs). In this study, the impacts of water constituents, namely, halides (including chloride (Cl−) and bromide (Br−)), bicarbonate (HCO3−) and natural organic matter (NOM) on SO4 − induced degradation of salbutamol (SAL) and terbutaline (TBL) were evaluated systematically. Our results indicated that chloride exhibited no effect on oxidation efficiencies of SAL and TBL, while Br−, HCO3− and NOM all showed inhibitory effects. Specifically, the detrimental effect of bromide was mainly attributed to the scavenging of SO4 − to form the less reactive species, Br2 −. By using laser flash photolysis (LFP), the second-order rate constants of Br2 − with SAL and TBL were estimated to be 2.1 and 3.9 × 108 M−1 s−1, respectively, much smaller than those with SO4 − (3.7 × 109 M−1 s−1 for SAL and 4.2 × 109 M−1 s−1 for TBL). Moreover, bromine addition products of SAL and TBL were detected in the presence of Br−, which were believed to be more toxic than the parent compounds. Similar to bromide, HCO3− could also quench SO4 − to generate carbonate Radical (CO3 −), also less reactive than Sulfate Radical with SAL (4.8 × 107 M−1 s−1) and TBL (3.2 × 108 M−1 s−1). In the case of NOM, a light screening effect was regarded as the major factor responsible to the decrease of reaction rates, while Sulfate Radical scavenging played a very limited role. The present work would increase the awareness of secondary reactions during SR-AOPs, as more toxic products were generated in the case of bromide.
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rethinking Sulfate Radical based oxidation of nitrophenols formation of toxic polynitrophenols nitrated biphenyls and diphenyl ethers
Journal of Hazardous Materials, 2019Co-Authors: L. Zhou, C. Ferronato, Yan Yang, Lu Wang, Yuanyuan Shi, Peizeng Yang, Lei Zhou, J. ChovelonAbstract:Abstract Sulfate Radical (SO4 −)-based oxidation of nitrophenols (NPs) have been widely studied; however, formation of potentially more toxic polynitroaromatic intermediates has been overlooked. In this contribution, we systematically investigated the degradation of four NPs by a SO4 −-based oxidation process. Degradation efficiency of NPs followed the order: 2-nitrophenol (2-NP) > 4-nitrophenol (4-NP) > 2,4-dinitrophenol (2,4-DNP) > 2,6-dinitrophenol (2,6-DNP). HPLC and LC–MS/MS analysis confirmed the formation of 2,4-DNP, 2,6-DNP and 2,4,6-trinitrophenol (2,4,6-TNP) during NPs transformation by SO4 −, suggesting that both denitration and renitration processes occurred. Nitrogen dioxide Radicals (NO2 ) and phenoxy Radicals are responsible for the formation of polynitrophenols. Coupling products including nitrated biphenyls and diphenyl ethers were also detected, which were proposed to be formed by combinations of resonance-stabilized Radicals. Electron spin density and charge density calculation showed that ortho C-ortho C and ortho C-phenolic O were the most likely combination ways responsible for coupling products formation. ECOSAR program predicted that polynitrated diphenyl ethers and biphenyls had higher ecotoxicological effects on aquatic species such as fish and daphnia. Therefore, the formation of toxic polynitroaromatic intermediates in SO4 −-based advanced oxidation processes should be scrutinized before this technology can be safely utilized for water and wastewater treatment.
Dionysios D. Dionysiou - One of the best experts on this subject based on the ideXlab platform.
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Limitations and prospects of Sulfate-Radical based advanced oxidation processes
Journal of Environmental Chemical Engineering, 2020Co-Authors: Xiaodi Duan, Shanshan Yang, Stanisław Wacławek, Guodong Fang, Ruiyang Xiao, Dionysios D. DionysiouAbstract:Abstract In recent years, there has been growing interest on the application of advanced oxidation processes (AOPs) based on Sulfate Radical in the elimination of organic contaminants. In such processes, Sulfate Radical is typically generated from the activation of peroxymonoSulfate (PMS) or peroxydiSulfate (PDS). In this paper, generation of Sulfate Radical by various methods and mechanism of activation processes for PMS or PDS were discussed. Moreover, certain applications of Sulfate Radical-based AOPs in wastewater, groundwater, and soil remediation were also summarized. More strategies, such as developing stable and highly efficient metal oxide activators, fabricating efficient carbonaceous-based materials, and combining with other treatment technologies, should be considered in further applications of Sulfate Radical-based advanced oxidation processes (SR-AOPs). In addition, more attention should be paid to elucidate the underlying mechanisms by coupling experimental analysis with theoretical models. The generation of toxic byproducts, high level of Sulfate ion, and complex quenching reactions are pointed out as main limitations. Finally, further studies on mechanistic aspects of the chemistry involved and evaluation of the potential for on-site applications are desired to further explore implementation of such SR-AOPs.
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mechanistic study on the role of soluble microbial products in Sulfate Radical mediated degradation of pharmaceuticals
Environmental Science & Technology, 2019Co-Authors: Lingwei Gao, Dionysios D. Dionysiou, Daisuke Minakata, Zongsu Wei, Richard Spinney, Chongjian Tang, Liyuan Chai, Ruiyang XiaoAbstract:The role of soluble microbial products (SMP), the most important component of effluent organic matter from municipal wastewater treatment plants, in Sulfate Radical (SO4•-)-based advanced oxidation technologies (AOTs) remains substantially unclear. In this study, we first utilized a suite of macro- and microanalytical techniques to characterize the SMP from a membrane bioreactor for its fundamental molecular, spectroscopic, and reactivity properties. The degradation kinetics of three representative pharmaceuticals (i.e., naproxen, gemfibrozil, and sulfadiazine) in the presence of SMP was significantly reduced as compared to in its absence. Possible mechanisms for the interference by SMP in degrading these target compounds (TCs) were investigated. The low percentage of bound TCs to SMP ruled out the cage effect. The measurement of steady-state 1O2 concentration indicated that formation of 1O2 upon UV irradiation on SMP was not primarily responsible for the degradation of TCs. However, the comparative and quenching results reveal that SMP absorbs UV light acting as an inner filter toward the TCs, and meanwhile scavenges SO4•- with a high second-order rate constant of 2.48 × 108 MC-1 s-1.
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Inactivation of pathogenic microorganisms by Sulfate Radical: Present and future
Chemical Engineering Journal, 2019Co-Authors: Ruiyang Xiao, Dionysios D. Dionysiou, Kai Liu, Lu Bai, Daisuke Minakata, Youngwoo Seo, Recep Kaya Göktaş, Tang Chongjian, Zongsu Wei, Richard SpinneyAbstract:Abstract In recent years, inactivation of pathogenic microorganisms by Sulfate Radical anion ( SO 4 · - ) has attracted increasing attention due to growing demands to control harmful disinfection byproducts and update water treatment systems for efficient microbial control. This critical review focuses on the basic principles and current research status of SO 4 · - -based inactivation technology, and for comparison includes OH-based inactivation of microorganisms. After a brief review of basic mechanisms of Radical reactions with biomolecules, the inactivation kinetics and mechanisms by SO 4 · - in various activation systems are summarized and discussed. We demonstrated that SO 4 · - oxidatively damages the cell membrane/wall, proteins, and genetic materials (i.e., DNA and RNA), resulting in the inactivation of the microorganisms. Finally, existing problems, challenges, and possible solutions in engineering applications, and future research directions are discussed.
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chlorate formation mechanism in the presence of Sulfate Radical chloride bromide and natural organic matter
Environmental Science & Technology, 2018Co-Authors: Shaodong Hou, Dionysios D. Dionysiou, Yuru Wang, Li Ling, Jiajia Huang, Kaiheng Guo, Jingyun FangAbstract:Halides and natural organic matter (NOM) are inevitable in aquatic environment and influence the degradation of contaminants in Sulfate Radical (SO4•–)-based advanced oxidation processes. This study investigated the formation of chlorate in the coexposure of SO4•–, chloride (Cl–), bromide (Br–) and/or NOM in UV/perSulfate (UV/PDS) and cobalt(II)/peroxymonoSulfate (Co/PMS) systems. The formation of chlorate increased with increasing Cl– concentration in the UV/PDS system, however, in the Co/PMS system, it initially increased and then decreased. The chlorate formation involved the formation of hypochlorous acid/hypochlorite (HOCl/OCl–) as an intermediate in both systems. The formation was primarily attributable to SO4•– in the UV/PDS system, whereas Co(III) played a significant role in the oxidation of Cl– to HOCl/OCl– and SO4•– was important for the oxidation of HOCl/OCl– to chlorate in the Co/PMS system. The pseudo-first-order rate constants (k′) of the transformation from Cl– to HOCl/OCl– were 3.32 × 10–...
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activation of peroxymonoSulfate perSulfate by nanomaterials for Sulfate Radical based advanced oxidation technologies
Current opinion in chemical engineering, 2018Co-Authors: Ruiyang Xiao, Zongsu Wei, Richard Spinney, Zonghao Luo, Shuang Luo, Weichun Yang, Dionysios D. DionysiouAbstract:Sulfate Radical anion (SO4 −) based advanced oxidation technologies (AOTs) have received a great deal of attention due to their high reactivity with the organic contaminants and high selectivity in complex environmental matrices. Among all SO4 − activation techniques, the heterogeneous activation of precursor peroxides such as peroxymonoSulfate (PMS) and perSulfate (PS) by nanostructured materials has demonstrated to be an effective method to generate SO4 −. This paper reviews SO4 − chemistry and the nanostructured materials that can effectively activate PMS/PS, namely, transition metal-based nano-catalysts, carbon nanomaterials, and nano-composites. In addition, we also discuss the activation mechanisms of PMS/PS initiated by heterogeneous nanostructured materials, emphasizing their catalytic activity, stability, and reusability for the removal of organic contaminants. This review shows that nanostructured materials have promising potential in environmental remediation based on their excellent catalytic efficiency, large specific surface area, and controllable structure. It also provides perspective on potential future studies on the design of novel nanostructured materials and process development in the field of SO4 − based AOTs.
C. Ferronato - One of the best experts on this subject based on the ideXlab platform.
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New insights into clopyralid degradation by Sulfate Radical: Pyridine ring cleavage pathways
Water Research, 2020Co-Authors: X. Yang, X. Ding, L. Zhou, H. Fan, X. Wang, C. Ferronato, J. Chovelon, G. XiuAbstract:Sulfate Radical
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New insights into clopyralid degradation by Sulfate Radical: Pyridine ring cleavage pathways.
Water Research, 2020Co-Authors: X. Yang, X. Ding, L. Zhou, X. Wang, C. Ferronato, J. Chovelon, Huan-huan Fan, G. XiuAbstract:Abstract Contamination by herbicides such as clopyralid (CLP) poses a significant threat to human health and ecological systems. In the present study, efficient removal of CLP was achieved by thermo activated perSulfate, among which Sulfate Radical was identified as the predominant oxidizing species responsible for the decontamination. Based on high resolution LC-MS, derivatization method and density functional theory (DFT) computation, the detailed oxidation pathways and mechanisms were proposed. The primary oxidation pathways included dechlorination-hydroxylation, decarboxylation and the formation of quinone-like moieties. Afterwards, numerous intermediate byproducts ranging from high molecular to very small ones were identified, suggesting the pyridine ring was damaged during the thermo activated perSulfate process. The detected products containing six and five carbons indicated the pyridine ring cleavage would take place on the quinone-structure intermediate. Further oxidation could continue by breaking each bond on the ring-cleavage product, yielding a series of short-chain carbonyl chemicals, carboxylic acids and inorganic ions. In addition, the presence of dissolved oxygen (DO) was favorable to CLP degradation, indicating DO played an important role in applying such technology. The degradation rate constants of CLP increased appreciably with increasing temperature, and acidic pH facilitated the CLP degradation. The results obtained in this work would increase our understanding on the environmental fates of nitrogen heterocyclic compounds during Sulfate Radical (SO4•−)-based advanced oxidation processes (SR-AOPs).
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Sulfate Radical mediated degradation of 5-halogenosalicylic acids: Phenoxyl Radical transformation pathways
Chemical Engineering Journal, 2020Co-Authors: L. Zhou, X. Yang, C. Ferronato, J. Chovelon, M. Sleiman, Qing Zhao, Claire RichardAbstract:Abstract In the present study, we investigated the degradation kinetics and transformation pathways of two 5-halogenosalicylic acids (5XSAs), namely, 5-chlorosalicylic acid (5ClSA) and 5-bromosalicylic acid (5BrSA) by Sulfate Radical (SO4•−) in a thermo-activated perSulfate system. The reaction pathways and mechanisms were proposed based on laser flash photolysis (LFP) techniques, HPLC-HRMS and molecular orbital calculations. Our results revealed that efficient removal of 5XSAs could be achieved by thermo-activated perSulfate, and phenoxyl Radicals were found to play key roles in the primary oxidation pathways. The subsequent transformation of phenoxyl Radicals included hydroxylation and coupling processes. The resulting coupling products could undergo secondary reactions with Sulfate Radical, including dehalogenation, decarboxylation and hydroxylation. Hydroxylated products were in turn oxidized by SO4•−, leading to the ring opening and the formation of a series of small molecular carbonyl byproducts. These processes could be responsible for the mineralization and the release of Br− or Cl−. In addition, the degradation rate constants of 5XSAs increased appreciably with increasing temperature, and higher efficiency of oxidation was observed around neutral initial pH. Moreover, degradation kinetics were found to be hardly affected by dissolved oxygen (DO), showing the possibility of applying SR-AOPs under environmental realistic conditions, not only for surface waters, but also for oxygen-deficient underground waters. The present work could increase our understanding on the reactivity and pathways of halogen phenols widely present in natural waters.
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Sulfate Radical induced degradation of β2 adrenoceptor agonists salbutamol and terbutaline implication of halides bicarbonate and natural organic matter
Chemical Engineering Journal, 2019Co-Authors: L. Zhou, X. Wang, C. Ferronato, J. Chovelon, M. Sleiman, Claire RichardAbstract:Abstract The presence of inorganic ions and organic matter in natural water would cause unpredictable consequence on the oxidation efficiency and pathways of Sulfate Radical (SO4 −) based advanced oxidation process (SR-AOPs). In this study, the impacts of water constituents, namely, halides (including chloride (Cl−) and bromide (Br−)), bicarbonate (HCO3−) and natural organic matter (NOM) on SO4 − induced degradation of salbutamol (SAL) and terbutaline (TBL) were evaluated systematically. Our results indicated that chloride exhibited no effect on oxidation efficiencies of SAL and TBL, while Br−, HCO3− and NOM all showed inhibitory effects. Specifically, the detrimental effect of bromide was mainly attributed to the scavenging of SO4 − to form the less reactive species, Br2 −. By using laser flash photolysis (LFP), the second-order rate constants of Br2 − with SAL and TBL were estimated to be 2.1 and 3.9 × 108 M−1 s−1, respectively, much smaller than those with SO4 − (3.7 × 109 M−1 s−1 for SAL and 4.2 × 109 M−1 s−1 for TBL). Moreover, bromine addition products of SAL and TBL were detected in the presence of Br−, which were believed to be more toxic than the parent compounds. Similar to bromide, HCO3− could also quench SO4 − to generate carbonate Radical (CO3 −), also less reactive than Sulfate Radical with SAL (4.8 × 107 M−1 s−1) and TBL (3.2 × 108 M−1 s−1). In the case of NOM, a light screening effect was regarded as the major factor responsible to the decrease of reaction rates, while Sulfate Radical scavenging played a very limited role. The present work would increase the awareness of secondary reactions during SR-AOPs, as more toxic products were generated in the case of bromide.
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rethinking Sulfate Radical based oxidation of nitrophenols formation of toxic polynitrophenols nitrated biphenyls and diphenyl ethers
Journal of Hazardous Materials, 2019Co-Authors: L. Zhou, C. Ferronato, Yan Yang, Lu Wang, Yuanyuan Shi, Peizeng Yang, Lei Zhou, J. ChovelonAbstract:Abstract Sulfate Radical (SO4 −)-based oxidation of nitrophenols (NPs) have been widely studied; however, formation of potentially more toxic polynitroaromatic intermediates has been overlooked. In this contribution, we systematically investigated the degradation of four NPs by a SO4 −-based oxidation process. Degradation efficiency of NPs followed the order: 2-nitrophenol (2-NP) > 4-nitrophenol (4-NP) > 2,4-dinitrophenol (2,4-DNP) > 2,6-dinitrophenol (2,6-DNP). HPLC and LC–MS/MS analysis confirmed the formation of 2,4-DNP, 2,6-DNP and 2,4,6-trinitrophenol (2,4,6-TNP) during NPs transformation by SO4 −, suggesting that both denitration and renitration processes occurred. Nitrogen dioxide Radicals (NO2 ) and phenoxy Radicals are responsible for the formation of polynitrophenols. Coupling products including nitrated biphenyls and diphenyl ethers were also detected, which were proposed to be formed by combinations of resonance-stabilized Radicals. Electron spin density and charge density calculation showed that ortho C-ortho C and ortho C-phenolic O were the most likely combination ways responsible for coupling products formation. ECOSAR program predicted that polynitrated diphenyl ethers and biphenyls had higher ecotoxicological effects on aquatic species such as fish and daphnia. Therefore, the formation of toxic polynitroaromatic intermediates in SO4 −-based advanced oxidation processes should be scrutinized before this technology can be safely utilized for water and wastewater treatment.
Claire Richard - One of the best experts on this subject based on the ideXlab platform.
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Sulfate Radical mediated degradation of 5-halogenosalicylic acids: Phenoxyl Radical transformation pathways
Chemical Engineering Journal, 2020Co-Authors: L. Zhou, X. Yang, C. Ferronato, J. Chovelon, M. Sleiman, Qing Zhao, Claire RichardAbstract:Abstract In the present study, we investigated the degradation kinetics and transformation pathways of two 5-halogenosalicylic acids (5XSAs), namely, 5-chlorosalicylic acid (5ClSA) and 5-bromosalicylic acid (5BrSA) by Sulfate Radical (SO4•−) in a thermo-activated perSulfate system. The reaction pathways and mechanisms were proposed based on laser flash photolysis (LFP) techniques, HPLC-HRMS and molecular orbital calculations. Our results revealed that efficient removal of 5XSAs could be achieved by thermo-activated perSulfate, and phenoxyl Radicals were found to play key roles in the primary oxidation pathways. The subsequent transformation of phenoxyl Radicals included hydroxylation and coupling processes. The resulting coupling products could undergo secondary reactions with Sulfate Radical, including dehalogenation, decarboxylation and hydroxylation. Hydroxylated products were in turn oxidized by SO4•−, leading to the ring opening and the formation of a series of small molecular carbonyl byproducts. These processes could be responsible for the mineralization and the release of Br− or Cl−. In addition, the degradation rate constants of 5XSAs increased appreciably with increasing temperature, and higher efficiency of oxidation was observed around neutral initial pH. Moreover, degradation kinetics were found to be hardly affected by dissolved oxygen (DO), showing the possibility of applying SR-AOPs under environmental realistic conditions, not only for surface waters, but also for oxygen-deficient underground waters. The present work could increase our understanding on the reactivity and pathways of halogen phenols widely present in natural waters.
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Sulfate Radical induced degradation of β2 adrenoceptor agonists salbutamol and terbutaline implication of halides bicarbonate and natural organic matter
Chemical Engineering Journal, 2019Co-Authors: L. Zhou, X. Wang, C. Ferronato, J. Chovelon, M. Sleiman, Claire RichardAbstract:Abstract The presence of inorganic ions and organic matter in natural water would cause unpredictable consequence on the oxidation efficiency and pathways of Sulfate Radical (SO4 −) based advanced oxidation process (SR-AOPs). In this study, the impacts of water constituents, namely, halides (including chloride (Cl−) and bromide (Br−)), bicarbonate (HCO3−) and natural organic matter (NOM) on SO4 − induced degradation of salbutamol (SAL) and terbutaline (TBL) were evaluated systematically. Our results indicated that chloride exhibited no effect on oxidation efficiencies of SAL and TBL, while Br−, HCO3− and NOM all showed inhibitory effects. Specifically, the detrimental effect of bromide was mainly attributed to the scavenging of SO4 − to form the less reactive species, Br2 −. By using laser flash photolysis (LFP), the second-order rate constants of Br2 − with SAL and TBL were estimated to be 2.1 and 3.9 × 108 M−1 s−1, respectively, much smaller than those with SO4 − (3.7 × 109 M−1 s−1 for SAL and 4.2 × 109 M−1 s−1 for TBL). Moreover, bromine addition products of SAL and TBL were detected in the presence of Br−, which were believed to be more toxic than the parent compounds. Similar to bromide, HCO3− could also quench SO4 − to generate carbonate Radical (CO3 −), also less reactive than Sulfate Radical with SAL (4.8 × 107 M−1 s−1) and TBL (3.2 × 108 M−1 s−1). In the case of NOM, a light screening effect was regarded as the major factor responsible to the decrease of reaction rates, while Sulfate Radical scavenging played a very limited role. The present work would increase the awareness of secondary reactions during SR-AOPs, as more toxic products were generated in the case of bromide.
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Sulfate Radical induced degradation of β2 adrenoceptor agonists salbutamol and terbutaline phenoxyl Radical dependent mechanisms
Water Research, 2017Co-Authors: L. Zhou, C. Ferronato, J. Chovelon, M. Sleiman, Pascal De Sainteclaire, Claire RichardAbstract:The present study investigated the reactivity and oxidation mechanisms of salbutamol (SAL) and terbutaline (TBL), two typical β2-adrenoceptor agonists, towards Sulfate Radical (SO4−) by using photo-activated perSulfate (PS). The reaction pathways and mechanisms were proposed based on products identification using high resolution HPLC-ESI-MS, laser flash photolysis (LFP) and molecular orbital calculations. The results indicated that SO4− was the dominant reactive species in the UV/PS process. The second-order rate constants of Sulfate Radical reaction with SAL and TBL were measured as (3.7 ± 0.3) × 109 and (4.2 ± 0.3) × 109 M−1 s−1 by LFP, respectively. For both SAL and TBL, phenoxyl Radicals were found to play key roles in the orientation of the primary pathways. For SAL, a benzophenone derivative was generated by oxidation of the phenoxyl Radical. However, in the case of TBL, the transformation of the phenoxyl Radical into benzoquinone was impossible. Instead, the addition of OSO3H on the aromatic ring was the major pathway. The same reactivity pattern was observed in the case of TBL structural analogs resorcinol and 3,5-dihydroxybenzyl alcohol. Our results revealed that basic conditions inhibited the decomposition of SAL and TBL, while, increasing PS dose enhanced the degradation. The present work could help for a better understanding of the difference in oxidation reactivity of substituted phenols widely present in natural waters.
