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Lu Wang - One of the best experts on this subject based on the ideXlab platform.
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DMAEMA-grafted cellulose as an imprinted adsorbent for the selective adsorption of 4-nitrophenol
'Springer Science and Business Media LLC', 2021Co-Authors: Lang Daning, Lu Wang, Shi Ming, Xu Xia, He Shixue, Yang Chao, Wu Ronglan, Wang Wei, Wang JideAbstract:4-Nitrophenol is a highly toxic environmental pollutant. It is a challenge to selectively remove it from a mixture of various pollutants. Herein, we report a study on the selective adsorption of 4-nitrophenol by using molecularly imprinted polymers (MIPs). The imprinted polymer was synthesized using cellulose as a framework, onto which, the complex of the imprinting molecule (i.e., 4-nitrophenol) and a candidate material [namely, 2-(dimethylamino)ethyl methacrylate. DMAEMA] was grafted. The obtained MIP showed an excellent adsorption capacity with good selectivity. Also, the adsorption of 4-nitrophenol by the obtained MIP was fast and the adsorbent exhibited good recyclability. The thermodynamics and kinetics of the adsorption process of 4-nitrophenol by MIP was thoroughly studied, where an otherwise-equivalent non-imprinted polymer was used as a control in the experiments. The selectivity of the MIP adsorbent for 4-niteophenol was evaluated by two types of experiments: (1) adsorption experiments in single-component adsorbate systems (containing 4-nitrophenol, 3-Nitrophenol, catechol, or hydroquinone), and (2) competitive adsorption experiments in binary adsorbate systems (containing 4-nitrophenol plus either 3-Nitrophenol, catechol or hydroquinone). The selectivity coefficient for 4-nitrophenols was twice of those of other phenols (that were all around 2), indicative of the extent of the affinity of MIPs to these phenolic compounds. The recyclability of the adsorbent was evaluated for 5 adsorption–desorption cycles, where the adsorption capacity of the last cycle remained over 90.2% of that of the first cycle.publishedVersio
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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: 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.
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the role of nitrite in sulfate radical based degradation of phenolic compounds an unexpected nitration process relevant to groundwater remediation by in situ chemical oxidation isco
Water Research, 2017Co-Authors: Lu Wang, C. Ferronato, Mengdi Jiang, J. ChovelonAbstract:Abstract As promising in-situ chemical oxidation (ISCO) technologies, sulfate radical-based advanced oxidation processes (SR-AOPs) are applied in wastewater treatment and groundwater remediation in recent years. In this contribution, we report for the first time that, thermally activated persulfate oxidation of phenol in the presence of nitrite (NO 2 − ), an anion widely present in natural waters, could lead to the formation of nitrated by-products including 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), and 2,6-dinitrophenol (2,6-DNP). Nitrogen dioxide radical (NO 2 • ), arising from SO 4 •− scavenging by NO 2 − , was proposed to be involved in the formation of nitrophenols as a nitrating agent. It was observed that nitrophenols accounted for approximately 70% of the phenol transformed under reaction conditions of [NO 2 − ] = 200 μM, [PS] = 2 mM and temperature of 50 °C. Increasing the concentration of NO 2 − remarkably enhanced the formation of nitrophenols but did not affect the transformation rate of phenol significantly. The degradation of phenol and the formation of nitrophenols were significantly influenced by persulfate dosage, solution pH and natural organic matter (NOM). Further studies on the degradation of other phenolic compounds, including 4-chlorophenol (4-CP), 4-hydroxybenzoic acid (4-HBA), and acetaminophen (ATP), verified the formation of their corresponding nitrated by-products as well. Therefore, formation of nitrated by-products is probably a common but overlooked phenomenon during SO 4 •− -based oxidation of phenolic compounds in the presence of NO 2 − . Nitroaromatic compounds are well known for their carcinogenicity, mutagenicity and genotoxicity, and are potentially persistent in the environment. The formation of nitrated organic by-products in SR-AOPs should be carefully scrutinized, and risk assessment should be carried out to assess possible health and ecological impacts.
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denitration and renitration processes in sulfate radical mediated degradation of nitrobenzene
Chemical Engineering Journal, 2017Co-Authors: Yuanyuan Shi, Lu WangAbstract:Abstract Nitrobenzene (NB) is a recalcitrant organic compound caused great environmental concerns. Sulfate radical-based advanced oxidation processes (SR-AOPs) are promising environmental remediation and wastewater treatment technologies. In this contribution, we observed that degradation of NB by thermally activated persulfate oxidation process resulted in the formation of a suite of intermediates including 2-nitrophenol (2-NP), 3-Nitrophenol (3-NP), 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), 2,6-dinitrophenol (2,6-DNP), and 2,4,6-trinitrophenol (2,4,6-TNP) as well as coupling products. The formation of the nitrophenols was suggested to follow the sequence of mononitrophenols → dinitrophenols → trinitrophenol. Time-dependent evolutions of mononitrophenols and dinitrophenols were illustrated and their formation mechanisms were proposed. The evolution patterns of mononitrophenols were fitted by sequential reaction kinetic model. The formation of polynitrated phenolic compounds suggests that both denitration and nitration processes occurred during SO 4 − -based oxidation of NB. Nitration agent (i.e., NO 2 ) arising from the conversion of nitro group upon SO 4 − /HO attack is proposed to play an important role in the formation of polynitrated compounds. TOC measurement revealed that mineralization was less efficient as compared with NB degradation. The presence of NO 2 − was found to inhibit the degradation of NB but promote the formation of 2,4-DNP. Temperature played an important role in both the degradation of NB and the distribution of products. Since polynitrated aromatics are more persistent and mutagenic, the results of this contribution suggest that particular attention should be paid to their formation during SO 4 − -based oxidation processes.
J. Chovelon - One of the best experts on this subject based on the ideXlab platform.
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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: 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.
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the role of nitrite in sulfate radical based degradation of phenolic compounds an unexpected nitration process relevant to groundwater remediation by in situ chemical oxidation isco
Water Research, 2017Co-Authors: Lu Wang, C. Ferronato, Mengdi Jiang, J. ChovelonAbstract:Abstract As promising in-situ chemical oxidation (ISCO) technologies, sulfate radical-based advanced oxidation processes (SR-AOPs) are applied in wastewater treatment and groundwater remediation in recent years. In this contribution, we report for the first time that, thermally activated persulfate oxidation of phenol in the presence of nitrite (NO 2 − ), an anion widely present in natural waters, could lead to the formation of nitrated by-products including 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), and 2,6-dinitrophenol (2,6-DNP). Nitrogen dioxide radical (NO 2 • ), arising from SO 4 •− scavenging by NO 2 − , was proposed to be involved in the formation of nitrophenols as a nitrating agent. It was observed that nitrophenols accounted for approximately 70% of the phenol transformed under reaction conditions of [NO 2 − ] = 200 μM, [PS] = 2 mM and temperature of 50 °C. Increasing the concentration of NO 2 − remarkably enhanced the formation of nitrophenols but did not affect the transformation rate of phenol significantly. The degradation of phenol and the formation of nitrophenols were significantly influenced by persulfate dosage, solution pH and natural organic matter (NOM). Further studies on the degradation of other phenolic compounds, including 4-chlorophenol (4-CP), 4-hydroxybenzoic acid (4-HBA), and acetaminophen (ATP), verified the formation of their corresponding nitrated by-products as well. Therefore, formation of nitrated by-products is probably a common but overlooked phenomenon during SO 4 •− -based oxidation of phenolic compounds in the presence of NO 2 − . Nitroaromatic compounds are well known for their carcinogenicity, mutagenicity and genotoxicity, and are potentially persistent in the environment. The formation of nitrated organic by-products in SR-AOPs should be carefully scrutinized, and risk assessment should be carried out to assess possible health and ecological impacts.
Yuanyuan Shi - One of the best experts on this subject based on the ideXlab platform.
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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: 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.
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denitration and renitration processes in sulfate radical mediated degradation of nitrobenzene
Chemical Engineering Journal, 2017Co-Authors: Yuanyuan Shi, Lu WangAbstract:Abstract Nitrobenzene (NB) is a recalcitrant organic compound caused great environmental concerns. Sulfate radical-based advanced oxidation processes (SR-AOPs) are promising environmental remediation and wastewater treatment technologies. In this contribution, we observed that degradation of NB by thermally activated persulfate oxidation process resulted in the formation of a suite of intermediates including 2-nitrophenol (2-NP), 3-Nitrophenol (3-NP), 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), 2,6-dinitrophenol (2,6-DNP), and 2,4,6-trinitrophenol (2,4,6-TNP) as well as coupling products. The formation of the nitrophenols was suggested to follow the sequence of mononitrophenols → dinitrophenols → trinitrophenol. Time-dependent evolutions of mononitrophenols and dinitrophenols were illustrated and their formation mechanisms were proposed. The evolution patterns of mononitrophenols were fitted by sequential reaction kinetic model. The formation of polynitrated phenolic compounds suggests that both denitration and nitration processes occurred during SO 4 − -based oxidation of NB. Nitration agent (i.e., NO 2 ) arising from the conversion of nitro group upon SO 4 − /HO attack is proposed to play an important role in the formation of polynitrated compounds. TOC measurement revealed that mineralization was less efficient as compared with NB degradation. The presence of NO 2 − was found to inhibit the degradation of NB but promote the formation of 2,4-DNP. Temperature played an important role in both the degradation of NB and the distribution of products. Since polynitrated aromatics are more persistent and mutagenic, the results of this contribution suggest that particular attention should be paid to their formation during SO 4 − -based oxidation processes.
Ashok Mulchandani - One of the best experts on this subject based on the ideXlab platform.
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biosensor for direct determination of fenitrothion and epn using recombinant pseudomonas putida js444 with surface expressed organophosphorous hydrolase 2 modified carbon paste electrode
Applied Biochemistry and Biotechnology, 2006Co-Authors: Yu Lei, Wilfred Chen, Priti Mulchandani, Ashok MulchandaniAbstract:A whole cell-based amperometric biosensor for highly selective, sensitive, rapid, and cost-effective determination of the organophosphate pesticides fenitrothion and ethyl p-nitrophenol thiobenzenephosphonate (EPN) is discussed. The biosensor comprised genetically engineered p-nitrophenol (PNP)-degrading bacteria Pseudomonas putida JS444 anchoring and displaying organophosphorous hydrolase (OPH) on its cell surface as biological sensing element and carbon paste electrode as the amperometric transducer. Surface-expressed OPH catalyzed the hydrolysis of organophosphorous pesticides such as fenitrothion and EPN to release PNP and 3-methyl-4-nitrophenol, respectively, which were subsequently degraded by the enzymatic machinery of P. putida JS444 through electrochemically active intermediates to the TCA cycle. The electrooxidization current of the intermediates was measured and correlated to the concentration of organophosphates. Operating at optimum conditions, 0.086 mg dry wt of cell operating at 600 mV of applied potential (vs Ag/AgCl reference) in 50 mM citratephosphate buffer, pH 7.5, with 50 μM CoCl2 at room temperature, the biosensor measured as low as 1.4 ppb of fenitrothion and 1.6 ppb of EPN. There was no interference from phenolic compounds, carbamate pesticides, triazine herbicides, or organophosphate pesticides without nitrophenyl substituent. The service life of the biosensor and the applicability to lake water were also demonstrated.
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amperometric microbial biosensor for p nitrophenol using moraxella sp modified carbon paste electrode
Biosensors and Bioelectronics, 2005Co-Authors: Priti Mulchandani, Yu Lei, Wilfred Chen, Carlos M Hangarter, Ashok MulchandaniAbstract:An amperometric microbial biosensor for highly specific, sensitive and rapid quantitative determination of p-nitrophenol was developed. The biosensor takes advantage of the ability of Moraxella sp. to specifically degrade p-nitrophenol to hydroquinone, a more electroactive compound than p-nitrophenol. The electrochemical oxidation current of hydroquinone formed in biodegradation of p-nitrophenol was measured at Moraxella sp.-modified carbon paste electrode and correlated to p-phenol concentrations. The optimum response was realized by electrode constructed using 15 mg of dry cell weight per 1 g of carbon paste and operating at 0.3 V (versus Ag/AgCl reference) in pH 7.5, 20 mM sodium phosphate buffer. Operating at these optimum conditions the biosensor had excellent selectivity against phenol derivatives and was able to measure as low as 20 nM (2.78 ppb) p-nitrophenol with very good accuracy and reproducibility. The biosensor was stable for approximately 3 weeks when stored at 4 °C. The applicability of the biosensor to measure p-nitrophenol in lake water was demonstrated.
Krzysztof Zwierz - One of the best experts on this subject based on the ideXlab platform.
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optimization of an enzymatic method for the determination of lysosomal n acetyl β d hexosaminidase and β glucuronidase in synovial fluid
Clinical Chemistry and Laboratory Medicine, 2006Co-Authors: Justyna Marciniak, Janusz Popko, Anna Zalewska, Krzysztof ZwierzAbstract:Background: Our goal was to develop a suitably sensitive assay for N-acetyl-p-D-hexosaminidase (HEX) and p-glucuronidase to allow their use as markers of joint diseases. Methods: We optimized a spectrophotometric method for the determination of lysosomally derived HEX and p-glucuronidase in synovial fluid on a microplate reader to improve its utility. HEX and p-glucuronidase act on the 4-nitrophenyl derivatives N-acetyl-β-glucosamine and β-D-glucuronide, respectively, to produce 4-nitrophenol, which can be measured at 405 nm on a microplate reader. Results: Maximum enzyme activity was observed at pH 4.7 in a citrate-phosphate buffer for HEX and at pH 4.5 in an acetate buffer for p-glucuronidase. A 10-μL sample with 30 μL of substrate solution and 40 μL of appropriate buffer produced measurable amounts of 4-nitrophenol after incubation for 60 min at 37°C. Reactions were terminated by the addition of 200 μL of 200 mM borate buffer (pH 9.8). Conclusions: The assay is sufficiently sensitive for small volumes of synovial fluid, and is useful for the clinical diagnosis of joint diseases.
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optimization of an enzymatic method for the determination of lysosomal n acetyl beta d hexosaminidase and beta glucuronidase in synovial fluid
Clinical Chemistry and Laboratory Medicine, 2006Co-Authors: Justyna Marciniak, Janusz Popko, Anna Zalewska, Krzysztof ZwierzAbstract:Background Our goal was to develop a suitably sensitive assay for N-acetyl-beta-D-hexosaminidase (HEX) and beta-glucuronidase to allow their use as markers of joint diseases. Methods We optimized a spectrophotometric method for the determination of lysosomally derived HEX and beta-glucuronidase in synovial fluid on a microplate reader to improve its utility. HEX and beta-glucuronidase act on the 4-nitrophenyl derivatives N-acetyl-beta-glucosamine and beta-D-glucuronide, respectively, to produce 4-nitrophenol, which can be measured at 405 nm on a microplate reader. Results Maximum enzyme activity was observed at pH 4.7 in a citrate-phosphate buffer for HEX and at pH 4.5 in an acetate buffer for beta-glucuronidase. A 10-microL sample with 30 microL of substrate solution and 40 microL of appropriate buffer produced measurable amounts of 4-nitrophenol after incubation for 60 min at 37 degrees Celsius. Reactions were terminated by the addition of 200 microL of 200 mM borate buffer (pH 9.8). Conclusions The assay is sufficiently sensitive for small volumes of synovial fluid, and is useful for the clinical diagnosis of joint diseases.