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Coupling rotating disk electrodes and surface-enhanced Raman spectroscopy for in situ electrochemistry studies. Electrochem commun 2021. [DOI: 10.1016/j.elecom.2021.106928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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2
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Liu S, Han W, Korshin GV. Effects of fulvic acids on the electrochemical reactions and mass transfer properties of organic cation toluidine blue: Results of measurements by the method of rotating ring-disc electrode. WATER RESEARCH 2020; 184:116151. [PMID: 32682080 DOI: 10.1016/j.watres.2020.116151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/19/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
This study examined effects of aquatic and soil natural organic matter (NOM) exemplified by standard Suwannee River fulvic acid (SRFA) and Pahokee Peat fulvic acid (PPFA), respectively, on the electrochemical (EC) reactivity and mass transfer properties of the cationic organic probe toluidine blue (TB) that forms complexes with NOM. EC measurements that were carried out using the method of rotating ring-disc electrode (RRDE) showed that for disc potentials below -0.4 V vs. the standard Ag/AgCl reference electrode, TB molecules undergo EC reduction accompanied by the formation of EC-active products that undergo oxidation at the ring electrode. EC reactions of TB in the range of potentials -0.2 to -0.4 V were determined to involve free TB+ cations and TB species adsorbed on the electrode surface. The EC reduction of TB species at the disc potentials < -0.4 V was controlled by the mass transfer of the free TB+ cations and TB/NOM complexes to the electrode surface. Formation of TB/NOM complexes caused the mass transfer-controlled TB currents to undergo a consistent decrease. The observed changes were correlated with the extent of TB/NOM complexation and decreases of the diffusion coefficients of TB/NOM complexes that have higher molecular weights (MW) than the free cations. Properties of the intermediates formed upon the reduction of TB+ cations were also affected by NOM. These results demonstrate that RRDE measurements of EC reactions of TB or possibly other EC active probes allow probing the complexation of EC-active organic species with NOM and mass transfer properties of NOM complexes and ultimately NOM itself.
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Affiliation(s)
- Siqi Liu
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing, 210094, China; Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, 98195-2700, USA
| | - Weiqing Han
- Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing, 210094, China.
| | - Gregory V Korshin
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, 98195-2700, USA.
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Zhang C, Chen B, Korshin GV, Kuznetsov AM, Roccaro P, Yan M, Ni J. Comparison of the yields of mono-, Di- and tri-chlorinated HAAs and THMs in chlorination and chloramination based on experimental and quantum-chemical data. WATER RESEARCH 2020; 169:115100. [PMID: 31669900 DOI: 10.1016/j.watres.2019.115100] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 09/09/2019] [Accepted: 09/19/2019] [Indexed: 06/10/2023]
Abstract
Thermodynamic and kinetic aspects of the formation of trihalomethanes and haloacetic acids determined based on the quantum chemical (QC) simulations were compared in this study with the experimental data generated using the differential spectroscopy approach in chlorination and chloramination. The ratios of the slopes of the correlations between -DlnA350 values and individual DBPs concentrations (SNH2Cl/SHOCl) were observed to be linearly correlated with the ratios of the Gibbs free energies (ΔGNH2Cl/ΔGHOCl) of the corresponding reactions of chloramine and chlorine with acetaldehyde which was used as a model DBP precursor in QC simulations. Further QC examination of the kinetics of chlorination and chloramination of the model compound acetoacetic acid showed that the activation energy of reactions between monochloramine that directly participates in substitution reactions to form mono-, di and tri-halogenated intermediates are 2-3 times higher than those of HOCl formed via the hydrolysis monochloramine. This result confirms that the interactions of chloramine with NOM and ensuing DBP formation are primarily mediated by the free chlorine released as a result of the hydrolysis of monochloramine while direct halogenation of NOM by monochloramine is likely to provide a small contribution to DBP formation.
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Affiliation(s)
- Chenyang Zhang
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
| | - Bingya Chen
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
| | - Gregory V Korshin
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA, 98195-2700, United States
| | - Andrey M Kuznetsov
- Department of Inorganic Chemistry, Kazan National Research Technological University, K. Marx Street 68, Russian Federation, 420015
| | - Paolo Roccaro
- Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95123, Catania, Italy
| | - Mingquan Yan
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China.
| | - Jinren Ni
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
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Masliy AN, Grishaeva TN, Kuznetsov AM. Standard Redox Potentials of Fe(III) Aqua Complexes Included into the Cavities of Cucurbit[ n]urils ( n = 6-8): A DFT Forecast. J Phys Chem A 2019; 123:5341-5346. [PMID: 31199631 DOI: 10.1021/acs.jpca.9b04053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
An approach for estimating at the DFT level of the standard redox potentials of the inclusion compounds based on Fe(III) and Fe(II) aqua complexes inside the cavities of cucurbit[ n]urils ( n = 6-8) has been proposed. These inclusion compounds were established to have compositions which can be described by the formulas [Fe(H2O)6]3+/2+@CB[6] and [Fe(H2O)6·4H2O]3+/2+@CB[7,8]. Redox potentials E0 relative to the standard hydrogen electrode for the half-reaction Fe(III)/Fe(II) in the CB[ n] cavities calculated at the PBE/TZVP level within the molecular-continuum solvation model are 1.607, 0.949, and 0.847 V for n = 6, 7, and 8, respectively. The obtained values indicate a relative increase of the oxidative ability of Fe(III) aqua-ions in the cavities of the examined CB[ n], especially in CB[6], compared to the calculated value ( E0 = 0.786 V) for the same half-reaction in the bulk of aqueous solution. Possible causes of the detected trend are discussed. The calculations also showed that the Fe(III) aqua complex inside the CB[6] changes its magnetic properties, transforming into a low-spin state with a total spin S = 1/2, whereas for all other systems high-spin states in accord with the classical ligand field theory are realized.
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Affiliation(s)
- A N Masliy
- Department of Inorganic Chemistry , Kazan National Research Technological University , K. Marx Street 68 , 420015 Kazan , Russian Federation
| | - T N Grishaeva
- Department of Inorganic Chemistry , Kazan National Research Technological University , K. Marx Street 68 , 420015 Kazan , Russian Federation
| | - A M Kuznetsov
- Department of Inorganic Chemistry , Kazan National Research Technological University , K. Marx Street 68 , 420015 Kazan , Russian Federation
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Yan M, Chen Z, Li N, Zhou Y, Zhang C, Korshin G. Electrochemical reductive dehalogenation of iodine-containing contrast agent pharmaceuticals: Examination of reactions of diatrizoate and iopamidol using the method of rotating ring-disc electrode (RRDE). WATER RESEARCH 2018; 136:104-111. [PMID: 29500971 DOI: 10.1016/j.watres.2018.02.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/14/2018] [Accepted: 02/17/2018] [Indexed: 06/08/2023]
Abstract
This study examined the electrochemical (EC) reduction of iodinated contrast media (ICM) exemplified by iopamidol and diatrizoate. The method of rotating ring-disc electrode (RRDE) was used to elucidate rates and mechanisms of the EC reactions of the selected ICMs. Experiments were carried at varying hydrodynamic conditions, concentrations of iopamidol, diatrizoate, natural organic matter (NOM) and model compounds (resorcinol, catechol, guaiacol) which were used to examine interactions between products of the EC reduction of ICMs and halogenation-active species. The data showed that iopamidol and diatrizoate were EC-reduced at potentials < -0.45 V vs. s.c.e. In the range of potentials -0.65 to -0.85 V their reduction was mass transfer-controlled. The presence of NOM and model compounds did not affect the EC reduction of iopamidol and diatrizoate but active iodine species formed as a result of the EC-induced transformations of these ICMs reacted readily with NOM and model compounds. These data provide more insight into the nature of generation of iodine-containing by-products in the case of reductive degradation of ICMs.
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Affiliation(s)
- Mingquan Yan
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China.
| | - Zhanghao Chen
- School of Resources and Materials, Northeastern University at Qinhuangdao, No. 143, Taishan Road, Qinhuangdao, Hebei, 066004, China
| | - Na Li
- School of Resources and Materials, Northeastern University at Qinhuangdao, No. 143, Taishan Road, Qinhuangdao, Hebei, 066004, China
| | - Yuxuan Zhou
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
| | - Chenyang Zhang
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
| | - Gregory Korshin
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA, 98195-2700, United States
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Zhang C, Li M, Han X, Yan M. Quantum Chemical Examination of the Sequential Halogen Incorporation Scheme for the Modeling of Speciation of I/Br/Cl-Containing Trihalomethanes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2162-2169. [PMID: 29357232 DOI: 10.1021/acs.est.7b03871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The recently developed three-step ternary halogenation model interprets the incorporation of chlorine, bromine, and iodine ions into natural organic matter (NOM) and formation of iodine-, bromine-, and chlorine-containing trihalomethanes (THMs) based on the competition of iodine, bromine, and chlorine species at each node of the halogenation sequence. This competition is accounted for using the dimensionless ratios (denoted as γ) of kinetic rates of reactions of the initial attack sites or halogenated intermediates with chlorine, bromine, and iodine ions. However, correlations between the model predictions made and mechanistic aspects of the incorporation of halogen species need to be ascertained in more detail. In this study, quantum chemistry calculations were first used to probe the formation mechanism of 10 species of Cl-/Br-/I- THMs. The HOMO energy (EHOMO) of each mono-, bi-, or trihalomethanes were calculated by B3LYP method in Gaussian 09 software. Linear correlations were found to exist between the logarithms of experimentally determined kinetic preference coefficients γ reported in prior research and, on the other hand, differences of EHOMO values between brominated/iodinated and chlorinated halomethanes. One notable exception from this trend was that observed for the incorporation of iodine into mono- and di-iodinated intermediates. These observations confirm the three-step halogen incorporation sequence and the factor γ in the statistical model. The combined use of quantum chemistry calculations and the ternary sequential halogenation model provides a new insight into the microscopic nature of NOM-halogen interactions and the trends seen in the behavior of γ factors incorporated in the THM speciation models.
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Affiliation(s)
- Chenyang Zhang
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education , Beijing 100871, China
| | - Maodong Li
- Center for Quantitative Biology, Peking University , Beijing 100871, China
| | - Xuze Han
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education , Beijing 100871, China
| | - Mingquan Yan
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education , Beijing 100871, China
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Chen G, Liu H. Understanding the Reduction Kinetics of Aqueous Vanadium(V) and Transformation Products Using Rotating Ring-Disk Electrodes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:11643-11651. [PMID: 28902987 DOI: 10.1021/acs.est.7b02021] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Vanadium(V) is an emerging contaminant in the most recent Environmental Protection Agency's candidate contaminant list (CCL4). The redox chemistry of vanadium controls its occurrence in the aquatic environment, but the impact of vanadium(V) speciation on the redox properties remains largely unknown. This study utilized the rotating ring-disk electrode technique to examine the reduction kinetics of four pH- and concentration-dependent vanadium(V) species in the presence and the absence of phosphate. Results showed that the reduction of VO2+, HxV4O12+x(4+x)- (V4), and HVO42- proceeded via a one-electron transfer, while that of NaxHyV10O28(6-x-y)- (V10) underwent a two-electron transfer. Koutecky-Levich and Tafel analyses showed that the intrinsic reduction rate constants followed the order of V10 > VO2+ > V4 > HVO42-. Ring-electrode collection efficiency indicated that the reduction product of V10 was stable, while those of VO2+, HVO42-, and V4 had short half-lives that ranged from milliseconds to seconds. With molar ratios of phosphate to vanadium(V) varying from 0 to 1, phosphate accelerated the reduction kinetics of V10 and V4 and enhanced the stability of the reduction products of VO2+, V4, and HVO42-. This study suggests that phosphate complexation could enhance the reductive removal of vanadium(V) and inhibit the reoxidation of its reduction product in water treatment.
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Affiliation(s)
- Gongde Chen
- Department of Chemical and Environmental Engineering, University of California at Riverside , Riverside, California 92521 United States
| | - Haizhou Liu
- Department of Chemical and Environmental Engineering, University of California at Riverside , Riverside, California 92521 United States
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Jiang J, Zhang X, Zhu X, Li Y. Removal of Intermediate Aromatic Halogenated DBPs by Activated Carbon Adsorption: A New Approach to Controlling Halogenated DBPs in Chlorinated Drinking Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:3435-3444. [PMID: 28199792 DOI: 10.1021/acs.est.6b06161] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
During chlorine disinfection of drinking water, chlorine may react with natural organic matter (NOM) and bromide ion in raw water to generate halogenated disinfection byproducts (DBPs). To mitigate adverse effects from DBP exposure, granular activated carbon (GAC) adsorption has been considered as one of the best available technologies for removing NOM (DBP precursor) in drinking water treatment. Recently, we have found that many aromatic halogenated DBPs form in chlorination, and they act as intermediate DBPs to decompose and form commonly known DBPs including trihalomethanes and haloacetic acids. In this work, we proposed a new approach to controlling drinking water halogenated DBPs by GAC adsorption of intermediate aromatic halogenated DBPs during chlorination, rather than by GAC adsorption of NOM prior to chlorination (i.e., traditional approach). Rapid small-scale column tests were used to simulate GAC adsorption in the new and traditional approaches. Significant reductions of aromatic halogenated DBPs were observed in the effluents with the new approach; the removals of total organic halogen, trihalomethanes, and haloacetic acids by the new approach always exceeded those by the traditional approach; and the effluents with the new approach were considerably less developmentally toxic than those with the traditional approach. Our findings indicate that the new approach is substantially more effective in controlling halogenated DBPs than the traditional approach.
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Affiliation(s)
- Jingyi Jiang
- Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology , Hong Kong, China
| | - Xiangru Zhang
- Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology , Hong Kong, China
| | - Xiaohu Zhu
- Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology , Hong Kong, China
| | - Yu Li
- Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology , Hong Kong, China
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