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首页> 外文期刊>Environmental Science & Technology >Kinetics and Mechanistic Aspects of As(lll)Oxidation by Aqueous Chlorine,Chloramines,and Ozone:Relevance to Drinking Water Treatment
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Kinetics and Mechanistic Aspects of As(lll)Oxidation by Aqueous Chlorine,Chloramines,and Ozone:Relevance to Drinking Water Treatment

机译：氯，氯胺和臭氧对As（III）氧化的动力学和力学方面：与饮用水处理的相关性

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摘要

Kinetics and mechanisms of As(lll)oxidation by free available chlorine (FAC-the sum of HOCl and OCl~(-1)),ozone (O_3),and monochloramine (NH_2CI)were investigated in buffered reagent solutions.Each reaction was found to befirstorderin oxidant and in As(lll),with 1:1 stoichiometry.FAC-As(lll)and O_3-As(III)reactions were extremely fast,with pH-dependent,apparent second-order rate constants,K"_app of 2.6 (+-0.1)x 10~5 M~(-1)s~(-1)and 1.5 (+-0.1)x 10~6 M~(-1)s~(-1)at pH 7,whereas the NH_2CI-As(lll)reaction was relatively slow (k"_(app) = 4.3 (+-1.7)x 10~(-1)M~(-1)s~(-1)at pH 7).Experiments conducted in real water samples spiked with 50 mu g/L As(III)(6.7 x 10~(-7)M)showed that a 0.1 mg/L Cl_2 (1.4 x 10~(-6)M)dose as FAC was sufficient to achieve depletion of As(III)to <1 mu g/L As(III)within 10 s of oxidant addition to waters containing negligible NH_3 concentrations and DOC concentrations <2 mg-C/L Even in a water containing 1 mg-N/L (7.1 x 10~(-5)M)as NH_3,>75% As(III)oxidation could be achieved within 10 s of dosing 1-2 mg/L Cl_2 (1.4-2.8 x 10~(-5)M)as FAC.As(III)residuals remaining in NH_3-containing waters 10 s after dosing FAC were slowly oxidized (f_1/_2 >= 4 h)in the presence of NH_2CI formed by the FAC-NH3 reaction.Ozonation was sufficient to yield >99% depletion of 50 mu g/L As(III)within 10 s of dosing 0.25 mg/L 0_3 (5.2 x 10(-6)M)to real waters containing <2 mg-C/L of DOC,while 0.8 mg/L O_3 (1.7 x 10~(-5)M)was sufficientfor a water containing 5.4 mg-C/L of DOC.NH_3 had negligible effect on the efficiency of As(III)oxidation by 0_3,due to the slow kinetics of the O_3-NH_3 reaction at circumneutral pH.Time-resolved measurements of As(III)loss during chlorinationdegradation in combination with low bioaccessibility of heavier PAHs is proposed to lead to a likely increase in concentration of heavier PAHs over time.These residues are,however,likely to be of low biological significance.
机译：在缓冲试剂溶液中研究了游离氯（FAC-HOCl和OCl〜（-1）之和），臭氧（O_3）和一氯胺（NH_2Cl）氧化As（III）的动力学和机理。在氧化剂和As（III）中是一阶的，化学计量比为1：1。FAC-As（III）和O_3-As（III）反应非常快，具有pH依赖性，表观二阶速率常数，K“ _app在pH 7时为2.6（+ -0.1）x 10〜5 M〜（-1）s〜（-1）和1.5（+ -0.1）x 10〜6 M〜（-1）s〜（-1） NH_2Cl-As（III）反应相对较慢（在pH 7时k“ _（app）= 4.3（+ -1.7）x 10〜（-1）M〜（-1）s〜（-1））。在掺有50μg / L As（III）（6.7 x 10〜（-7）M）的真实水样中进行的实验表明，0.1 mg / L Cl_2（1.4 x 10〜（-6）M）的FAC剂量为即使在含有1 mg-L的NH_3浓度和DOC浓度<2 mg-C / L的水中添加氧化剂，在10秒钟内足以将As（III）消耗至<1μg/ L As（III） N / L（7.1 x 10〜（-5）M）NH_3，> 75％As（III）氧化剂量为1-2 mg / L Cl_2（1.4-2.8 x 10〜（-5）M）的FAC剂量在10 s内达到.FAC剂量10 s后残留在NH_3水中的As（III）残留物被缓慢氧化（f_1 / _2> = 4 h）在FAC-NH3反应形成的NH_2Cl存在下进行臭氧处理，足以在0.25 mg / L 0_3的10 s内消耗> 99％的50μg/ L As（III）耗尽（ DOC小于2 mg-C / L的真实水为5.2 x 10（-6）M），而5.4 mg-C / L的水为0.8 mg / L O_3（1.7 x 10〜（-5）M）就足够了DOC.NH_3的L对在0〜3的O_3-NH_3反应的动力学很慢，对As（III）氧化效率的影响可忽略不计。氯化物降解过程中As（III）损失的时间分辨测量与有人提出，较重的PAHs的生物利用度低会导致较重的PAHs的浓度随时间升高。这些残基可能具有较低的生物学意义。

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  • 来源
    《Environmental Science & Technology》 |2006年第10期|p.3285-3292|共8页
  • 作者

    MICHAEL C.DODD; NGOC DUY VU; ADRIAN AMMANN; REINHARD KISSNER; THE HA CAO;

  • 作者单位

    Swiss Federal Institute of Aquatic Science and Technology (EAWAG),8600 Duebendorf,Switzerland,Center for Environmental Technology and Sustainable Development (CETASD),Hanoi University of Science,Nguyen Trai Street 334,Hanoi,Vietnam,and Laboratory of;

    Swiss Federal Institute of Aquatic Science and Technology (EAWAG),8600 Duebendorf,Switzerland,Center for Environmental Technology and Sustainable Development (CETASD),Hanoi University of Science,Nguyen Trai Street 334,Hanoi,Vietnam,and Laboratory of;

    Swiss Federal Institute of Aquatic Science and Technology (EAWAG),8600 Duebendorf,Switzerland,Center for Environmental Technology and Sustainable Development (CETASD),Hanoi University of Science,Nguyen Trai Street 334,Hanoi,Vietnam,and Laboratory of;

    Swiss Federal Institute of Aquatic Science and Technology (EAWAG),8600 Duebendorf,Switzerland,Center for Environmental Technology and Sustainable Development (CETASD),Hanoi University of Science,Nguyen Trai Street 334,Hanoi,Vietnam,and Laboratory of;

    Swiss Federal Institute of Aquatic Science and Technology (EAWAG),8600 Duebendorf,Switzerland,Center for Environmental Technology and Sustainable Development (CETASD),Hanoi University of Science,Nguyen Trai Street 334,Hanoi,Vietnam,and Laboratory of;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境化学;
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