The Experts below are selected from a list of 4575 Experts worldwide ranked by ideXlab platform
Hironao Sajiki - One of the best experts on this subject based on the ideXlab platform.
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platinum on carbon catalyzed hydroDefluorination of fluoroarenes using isopropyl alcohol water sodium carbonate combination
Advanced Synthesis & Catalysis, 2012Co-Authors: Yoshinari Sawama, Yuki Yabe, Masahiro Shigetsura, Saori Nagata, Yuta Fujiwara, Yasunari Monguchi, Tomohiro Maegawa, Tsuyoshi Yamada, Hironao SajikiAbstract:We have developed a platinum on carbon-isopropyl alcohol-catalyzed and widely applicable Defluorination method for fluoroarenes, and the addition of water and sodium carbonate efficiently accelerated the reaction. The Defluorination readily occurred under the reaction conditions in comparison with the dehalogenation of other aromatic halides (fluorine>chlorine>bromine≫iodine).
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Platinum on Carbon‐Catalyzed HydroDefluorination of Fluoroarenes using Isopropyl Alcohol‐Water‐Sodium Carbonate Combination
Advanced Synthesis & Catalysis, 2012Co-Authors: Yoshinari Sawama, Yuki Yabe, Masahiro Shigetsura, Saori Nagata, Yuta Fujiwara, Yasunari Monguchi, Tomohiro Maegawa, Tsuyoshi Yamada, Hironao SajikiAbstract:We have developed a platinum on carbon-isopropyl alcohol-catalyzed and widely applicable Defluorination method for fluoroarenes, and the addition of water and sodium carbonate efficiently accelerated the reaction. The Defluorination readily occurred under the reaction conditions in comparison with the dehalogenation of other aromatic halides (fluorine>chlorine>bromine≫iodine).
She-wei Yang - One of the best experts on this subject based on the ideXlab platform.
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photochemical Defluorination of aqueous perfluorooctanoic acid pfoa by vuv fe3 system
Chemical Engineering Journal, 2014Co-Authors: Jianhua Cheng, Xiao-yan Liang, She-wei YangAbstract:Abstract Perfluorooctanoic acid (PFOA), which is a typical perfluorinated acid, is bioaccumulative and extremely resistant to environmental degradation processes. In this study, a combined process using vacuum ultraviolet light (λ = 185 nm) and trivalent iron ions (VUV/Fe3+) was used to defluorinate aqueous PFOA. PFOA could be efficiently defluorinated under acidic condition (pH = 3–4), with a molar ratio of PFOA/Fe3+ between 1.8:1 and 1.2:1. Moreover, the decomposition mechanism of PFOA was also investigated. In addition to fluoride ions, other intermediates produced during PFOA decomposition were identified and quantified using HPLC/MS/MS, including six shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4, C3 and C2. Our results indicated that direct light degradation played a major role in PFOA Defluorination under VUV radiation (λ = 185 nm), while the Defluorination of PFOA was simultaneously photocatalytically decomposed and defluorinated in the presence of ferric ion (λ = 254 nm). Additional Fe3+ enhanced the Defluorination of PFOA and intermediates under VUV radiation.
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Photochemical Defluorination of aqueous perfluorooctanoic acid (PFOA) by VUV/Fe3+ system
Chemical Engineering Journal, 2014Co-Authors: Jianhua Cheng, Xiao-yan Liang, She-wei YangAbstract:Abstract Perfluorooctanoic acid (PFOA), which is a typical perfluorinated acid, is bioaccumulative and extremely resistant to environmental degradation processes. In this study, a combined process using vacuum ultraviolet light (λ = 185 nm) and trivalent iron ions (VUV/Fe3+) was used to defluorinate aqueous PFOA. PFOA could be efficiently defluorinated under acidic condition (pH = 3–4), with a molar ratio of PFOA/Fe3+ between 1.8:1 and 1.2:1. Moreover, the decomposition mechanism of PFOA was also investigated. In addition to fluoride ions, other intermediates produced during PFOA decomposition were identified and quantified using HPLC/MS/MS, including six shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4, C3 and C2. Our results indicated that direct light degradation played a major role in PFOA Defluorination under VUV radiation (λ = 185 nm), while the Defluorination of PFOA was simultaneously photocatalytically decomposed and defluorinated in the presence of ferric ion (λ = 254 nm). Additional Fe3+ enhanced the Defluorination of PFOA and intermediates under VUV radiation.
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Defluorination of Aqueous Perfluorooctanesulfonate by Activated Persulfate Oxidation
PloS one, 2013Co-Authors: She-wei Yang, Jianhua Cheng, Jian Sun, Xiao-yan LiangAbstract:Activated persulfate oxidation technologies based on sulfate radicals were first evaluated for Defluorination of aqueous perfluorooctanesulfonate (PFOS). The influences of catalytic method, time, pH and K2S2O8 amounts on PFOS Defluorination were investigated. The intermediate products during PFOS Defluorination were detected by using LC/MS/MS. The results showed that the S2O82− had weak effect on the Defluorination of PFOS, while the PFOS was oxidatively defluorinated by sulfate radicals in water. The Defluorination efficiency of PFOS under various treatment was followed the order: HT (hydrothermal)/K2S2O8 > UV (ultraviolet)/K2S2O8 > Fe2+/K2S2O8 > US (ultrasound)/K2S2O8. Low pH was favorable for the PFOS Defluorination with sulfate radicals. Increase in the amount of S2O82− had positive effect on PFOS Defluorination. However, further increase in amounts of S2O82− caused insignificant improvement in PFOS Defluorination due to elimination of sulfate radicals under high concentration of S2O82−. CF3(CF2)nCOOH (n = 0–6) were detected as intermediates during PFOS Defluorination. Sulfate radicals oxidation and hydrolysis were the main mechanisms involved in Defluorination process of PFOS.
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Effect of vacuum ultraviolet on ultrasonic Defluorination of aqueous perfluorooctanesulfonate
Chemical Engineering Journal, 2013Co-Authors: She-wei Yang, Jianhua Cheng, Jian Sun, Xiao-yan LiangAbstract:Abstract This study represents the first use of ultraviolet (VUV, λ = 185 nm)-assisted ultrasound (US, f = 600 kHz) irradiation for the Defluorination of aqueous perfluorooctanesulfonate (PFOS) under air atmosphere. The effects of reaction time, pH, temperature and initial PFOS concentration on the Defluorination performance of VUV, US and VUV-assisted US systems were compared. The intermediates formed during PFOS Defluorination in both the US and VUV-assisted US system were detected using LC/MS/MS. The results showed that introduction of VUV enhanced the ultrasonic Defluorination efficiency of PFOS and the enhanced extents were depended on particular reaction condition. The Defluorination efficiency of PFOS (10 mg/L) reached up to 88.47% after 240 min at 283 K under VUV-assisted US irradiation, which is 12.01% higher than that achieved under US irradiation alone. Compared with that achieved by US irradiation alone, the Defluorination efficiency of PFOS (10 mg/L) increased by an average of 11.54% at pH levels of 5–7, 13.03% at 283–298 K and 11.65% at initial PFOS concentrations of 10–30 mg/L using the VUV-assisted US system. Low levels of short-chain perfluorinated carboxylic acids (PFCAs) were detected as the main intermediates in both the US and VUV-assisted US systems, and the concentrations of intermediates in VUV-assisted US system were lower than that in US alone system. The introduction of VUV radiation could provide more multiple approaches for Defluorination of both the PFOS and its intermediates, thus improving the ultrasonic Defluorination of PFOS under air atmosphere.
Jianhua Cheng - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of phosphotungstic acid-supported bimodal mesoporous silica-based catalyst for Defluorination of aqueous perfluorooctanoic acid under vacuum UV irradiation
Chemical Engineering Journal, 2018Co-Authors: Xia You, Fang-fang Xiao, Cao Yang, Jianhua ChengAbstract:Abstract Phosphotungstic acid (H3PW12O40, HPW)/bimodal mesoporous silica (BMS) multifunctional catalysts were prepared and employed as photocatalyst for perfluorooctanoic acid (PFOA) degradation under vacuum ultraviolet light (VUV). Lower PFOA concentration, appropriate HPW/BMS dosage (0.2 g·L−1) and acidic condition (pH = 3–4) were more favorable for PFOA Defluorination in VUV/HPW/BMS system. Furthermore, we analyzed the intermediates produced during PFOA decomposition by HPLC/MS/MS, which were shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4, C3 and C2. The Defluorination mechanism of PFOA was proposed, i.e., direct photolysis played an important role in PFOA Defluorination under VUV radiation (λ = 185 nm), while the Defluorination of PFOA was simultaneously photocatalytically decomposed and defluorinated in the presence of HPW/BMS (λ = 254 nm).
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photochemical Defluorination of aqueous perfluorooctanoic acid pfoa by vuv fe3 system
Chemical Engineering Journal, 2014Co-Authors: Jianhua Cheng, Xiao-yan Liang, She-wei YangAbstract:Abstract Perfluorooctanoic acid (PFOA), which is a typical perfluorinated acid, is bioaccumulative and extremely resistant to environmental degradation processes. In this study, a combined process using vacuum ultraviolet light (λ = 185 nm) and trivalent iron ions (VUV/Fe3+) was used to defluorinate aqueous PFOA. PFOA could be efficiently defluorinated under acidic condition (pH = 3–4), with a molar ratio of PFOA/Fe3+ between 1.8:1 and 1.2:1. Moreover, the decomposition mechanism of PFOA was also investigated. In addition to fluoride ions, other intermediates produced during PFOA decomposition were identified and quantified using HPLC/MS/MS, including six shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4, C3 and C2. Our results indicated that direct light degradation played a major role in PFOA Defluorination under VUV radiation (λ = 185 nm), while the Defluorination of PFOA was simultaneously photocatalytically decomposed and defluorinated in the presence of ferric ion (λ = 254 nm). Additional Fe3+ enhanced the Defluorination of PFOA and intermediates under VUV radiation.
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Photochemical Defluorination of aqueous perfluorooctanoic acid (PFOA) by VUV/Fe3+ system
Chemical Engineering Journal, 2014Co-Authors: Jianhua Cheng, Xiao-yan Liang, She-wei YangAbstract:Abstract Perfluorooctanoic acid (PFOA), which is a typical perfluorinated acid, is bioaccumulative and extremely resistant to environmental degradation processes. In this study, a combined process using vacuum ultraviolet light (λ = 185 nm) and trivalent iron ions (VUV/Fe3+) was used to defluorinate aqueous PFOA. PFOA could be efficiently defluorinated under acidic condition (pH = 3–4), with a molar ratio of PFOA/Fe3+ between 1.8:1 and 1.2:1. Moreover, the decomposition mechanism of PFOA was also investigated. In addition to fluoride ions, other intermediates produced during PFOA decomposition were identified and quantified using HPLC/MS/MS, including six shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4, C3 and C2. Our results indicated that direct light degradation played a major role in PFOA Defluorination under VUV radiation (λ = 185 nm), while the Defluorination of PFOA was simultaneously photocatalytically decomposed and defluorinated in the presence of ferric ion (λ = 254 nm). Additional Fe3+ enhanced the Defluorination of PFOA and intermediates under VUV radiation.
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Defluorination of Aqueous Perfluorooctanesulfonate by Activated Persulfate Oxidation
PloS one, 2013Co-Authors: She-wei Yang, Jianhua Cheng, Jian Sun, Xiao-yan LiangAbstract:Activated persulfate oxidation technologies based on sulfate radicals were first evaluated for Defluorination of aqueous perfluorooctanesulfonate (PFOS). The influences of catalytic method, time, pH and K2S2O8 amounts on PFOS Defluorination were investigated. The intermediate products during PFOS Defluorination were detected by using LC/MS/MS. The results showed that the S2O82− had weak effect on the Defluorination of PFOS, while the PFOS was oxidatively defluorinated by sulfate radicals in water. The Defluorination efficiency of PFOS under various treatment was followed the order: HT (hydrothermal)/K2S2O8 > UV (ultraviolet)/K2S2O8 > Fe2+/K2S2O8 > US (ultrasound)/K2S2O8. Low pH was favorable for the PFOS Defluorination with sulfate radicals. Increase in the amount of S2O82− had positive effect on PFOS Defluorination. However, further increase in amounts of S2O82− caused insignificant improvement in PFOS Defluorination due to elimination of sulfate radicals under high concentration of S2O82−. CF3(CF2)nCOOH (n = 0–6) were detected as intermediates during PFOS Defluorination. Sulfate radicals oxidation and hydrolysis were the main mechanisms involved in Defluorination process of PFOS.
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Effect of vacuum ultraviolet on ultrasonic Defluorination of aqueous perfluorooctanesulfonate
Chemical Engineering Journal, 2013Co-Authors: She-wei Yang, Jianhua Cheng, Jian Sun, Xiao-yan LiangAbstract:Abstract This study represents the first use of ultraviolet (VUV, λ = 185 nm)-assisted ultrasound (US, f = 600 kHz) irradiation for the Defluorination of aqueous perfluorooctanesulfonate (PFOS) under air atmosphere. The effects of reaction time, pH, temperature and initial PFOS concentration on the Defluorination performance of VUV, US and VUV-assisted US systems were compared. The intermediates formed during PFOS Defluorination in both the US and VUV-assisted US system were detected using LC/MS/MS. The results showed that introduction of VUV enhanced the ultrasonic Defluorination efficiency of PFOS and the enhanced extents were depended on particular reaction condition. The Defluorination efficiency of PFOS (10 mg/L) reached up to 88.47% after 240 min at 283 K under VUV-assisted US irradiation, which is 12.01% higher than that achieved under US irradiation alone. Compared with that achieved by US irradiation alone, the Defluorination efficiency of PFOS (10 mg/L) increased by an average of 11.54% at pH levels of 5–7, 13.03% at 283–298 K and 11.65% at initial PFOS concentrations of 10–30 mg/L using the VUV-assisted US system. Low levels of short-chain perfluorinated carboxylic acids (PFCAs) were detected as the main intermediates in both the US and VUV-assisted US systems, and the concentrations of intermediates in VUV-assisted US system were lower than that in US alone system. The introduction of VUV radiation could provide more multiple approaches for Defluorination of both the PFOS and its intermediates, thus improving the ultrasonic Defluorination of PFOS under air atmosphere.
Xiao-yan Liang - One of the best experts on this subject based on the ideXlab platform.
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photochemical Defluorination of aqueous perfluorooctanoic acid pfoa by vuv fe3 system
Chemical Engineering Journal, 2014Co-Authors: Jianhua Cheng, Xiao-yan Liang, She-wei YangAbstract:Abstract Perfluorooctanoic acid (PFOA), which is a typical perfluorinated acid, is bioaccumulative and extremely resistant to environmental degradation processes. In this study, a combined process using vacuum ultraviolet light (λ = 185 nm) and trivalent iron ions (VUV/Fe3+) was used to defluorinate aqueous PFOA. PFOA could be efficiently defluorinated under acidic condition (pH = 3–4), with a molar ratio of PFOA/Fe3+ between 1.8:1 and 1.2:1. Moreover, the decomposition mechanism of PFOA was also investigated. In addition to fluoride ions, other intermediates produced during PFOA decomposition were identified and quantified using HPLC/MS/MS, including six shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4, C3 and C2. Our results indicated that direct light degradation played a major role in PFOA Defluorination under VUV radiation (λ = 185 nm), while the Defluorination of PFOA was simultaneously photocatalytically decomposed and defluorinated in the presence of ferric ion (λ = 254 nm). Additional Fe3+ enhanced the Defluorination of PFOA and intermediates under VUV radiation.
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Photochemical Defluorination of aqueous perfluorooctanoic acid (PFOA) by VUV/Fe3+ system
Chemical Engineering Journal, 2014Co-Authors: Jianhua Cheng, Xiao-yan Liang, She-wei YangAbstract:Abstract Perfluorooctanoic acid (PFOA), which is a typical perfluorinated acid, is bioaccumulative and extremely resistant to environmental degradation processes. In this study, a combined process using vacuum ultraviolet light (λ = 185 nm) and trivalent iron ions (VUV/Fe3+) was used to defluorinate aqueous PFOA. PFOA could be efficiently defluorinated under acidic condition (pH = 3–4), with a molar ratio of PFOA/Fe3+ between 1.8:1 and 1.2:1. Moreover, the decomposition mechanism of PFOA was also investigated. In addition to fluoride ions, other intermediates produced during PFOA decomposition were identified and quantified using HPLC/MS/MS, including six shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4, C3 and C2. Our results indicated that direct light degradation played a major role in PFOA Defluorination under VUV radiation (λ = 185 nm), while the Defluorination of PFOA was simultaneously photocatalytically decomposed and defluorinated in the presence of ferric ion (λ = 254 nm). Additional Fe3+ enhanced the Defluorination of PFOA and intermediates under VUV radiation.
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Defluorination of Aqueous Perfluorooctanesulfonate by Activated Persulfate Oxidation
PloS one, 2013Co-Authors: She-wei Yang, Jianhua Cheng, Jian Sun, Xiao-yan LiangAbstract:Activated persulfate oxidation technologies based on sulfate radicals were first evaluated for Defluorination of aqueous perfluorooctanesulfonate (PFOS). The influences of catalytic method, time, pH and K2S2O8 amounts on PFOS Defluorination were investigated. The intermediate products during PFOS Defluorination were detected by using LC/MS/MS. The results showed that the S2O82− had weak effect on the Defluorination of PFOS, while the PFOS was oxidatively defluorinated by sulfate radicals in water. The Defluorination efficiency of PFOS under various treatment was followed the order: HT (hydrothermal)/K2S2O8 > UV (ultraviolet)/K2S2O8 > Fe2+/K2S2O8 > US (ultrasound)/K2S2O8. Low pH was favorable for the PFOS Defluorination with sulfate radicals. Increase in the amount of S2O82− had positive effect on PFOS Defluorination. However, further increase in amounts of S2O82− caused insignificant improvement in PFOS Defluorination due to elimination of sulfate radicals under high concentration of S2O82−. CF3(CF2)nCOOH (n = 0–6) were detected as intermediates during PFOS Defluorination. Sulfate radicals oxidation and hydrolysis were the main mechanisms involved in Defluorination process of PFOS.
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Effect of vacuum ultraviolet on ultrasonic Defluorination of aqueous perfluorooctanesulfonate
Chemical Engineering Journal, 2013Co-Authors: She-wei Yang, Jianhua Cheng, Jian Sun, Xiao-yan LiangAbstract:Abstract This study represents the first use of ultraviolet (VUV, λ = 185 nm)-assisted ultrasound (US, f = 600 kHz) irradiation for the Defluorination of aqueous perfluorooctanesulfonate (PFOS) under air atmosphere. The effects of reaction time, pH, temperature and initial PFOS concentration on the Defluorination performance of VUV, US and VUV-assisted US systems were compared. The intermediates formed during PFOS Defluorination in both the US and VUV-assisted US system were detected using LC/MS/MS. The results showed that introduction of VUV enhanced the ultrasonic Defluorination efficiency of PFOS and the enhanced extents were depended on particular reaction condition. The Defluorination efficiency of PFOS (10 mg/L) reached up to 88.47% after 240 min at 283 K under VUV-assisted US irradiation, which is 12.01% higher than that achieved under US irradiation alone. Compared with that achieved by US irradiation alone, the Defluorination efficiency of PFOS (10 mg/L) increased by an average of 11.54% at pH levels of 5–7, 13.03% at 283–298 K and 11.65% at initial PFOS concentrations of 10–30 mg/L using the VUV-assisted US system. Low levels of short-chain perfluorinated carboxylic acids (PFCAs) were detected as the main intermediates in both the US and VUV-assisted US systems, and the concentrations of intermediates in VUV-assisted US system were lower than that in US alone system. The introduction of VUV radiation could provide more multiple approaches for Defluorination of both the PFOS and its intermediates, thus improving the ultrasonic Defluorination of PFOS under air atmosphere.
Tomohiro Maegawa - One of the best experts on this subject based on the ideXlab platform.
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platinum on carbon catalyzed hydroDefluorination of fluoroarenes using isopropyl alcohol water sodium carbonate combination
Advanced Synthesis & Catalysis, 2012Co-Authors: Yoshinari Sawama, Yuki Yabe, Masahiro Shigetsura, Saori Nagata, Yuta Fujiwara, Yasunari Monguchi, Tomohiro Maegawa, Tsuyoshi Yamada, Hironao SajikiAbstract:We have developed a platinum on carbon-isopropyl alcohol-catalyzed and widely applicable Defluorination method for fluoroarenes, and the addition of water and sodium carbonate efficiently accelerated the reaction. The Defluorination readily occurred under the reaction conditions in comparison with the dehalogenation of other aromatic halides (fluorine>chlorine>bromine≫iodine).
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Platinum on Carbon‐Catalyzed HydroDefluorination of Fluoroarenes using Isopropyl Alcohol‐Water‐Sodium Carbonate Combination
Advanced Synthesis & Catalysis, 2012Co-Authors: Yoshinari Sawama, Yuki Yabe, Masahiro Shigetsura, Saori Nagata, Yuta Fujiwara, Yasunari Monguchi, Tomohiro Maegawa, Tsuyoshi Yamada, Hironao SajikiAbstract:We have developed a platinum on carbon-isopropyl alcohol-catalyzed and widely applicable Defluorination method for fluoroarenes, and the addition of water and sodium carbonate efficiently accelerated the reaction. The Defluorination readily occurred under the reaction conditions in comparison with the dehalogenation of other aromatic halides (fluorine>chlorine>bromine≫iodine).