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首页> 外文期刊>Environmental Science & Technology >Mechanistic Aspects of the Formation of Adsorbable Organic Bromine during Chiorination of Bromide-containing Synthetic Waters
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Mechanistic Aspects of the Formation of Adsorbable Organic Bromine during Chiorination of Bromide-containing Synthetic Waters

机译：含溴的合成水手性化过程中形成可吸附有机溴的机制方面

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摘要

During chiorination of bromide-containing waters, a significant formation of brominated disinfection byproducts is expected. This is of concern because Br-DBPs are generally more toxic than their chlorinated analogues. In this study, synthetic water samples containing dissolved organic matter (DOM) extracts and bromide were treated under various disinfection scenarios to elucidate the mechanisms of Br-DBP formation. The total concentration of Br-DBPs was measured as adsorbable organic bromine (AOBr). A portion of the bromine (HOBr) was found to react with DOM via electrophilic substitution (<40%), forming AOBr, and the remaining HOBr reacted with DOM via electron transfer with a reduction of HOBr to bromide (>60%). During chiorination, the released bromide is reoxidized (recycled) by chlorine to HOBr, leading to further electrophilic substitution of unaltered DOM sites and chlorinated DOM moieties. This leads to an almost complete bromine incorporation to DOM (>87%). The type of DOM (3.06 ≤ SUVA_(254) ≤ 4.85) is not affecting this process, as long as the bromine-reactive DOM sites are in excess and a sufficient chlorine exposure is achieved. When most reactive sites were consumed by chlorine, Cl-substituted functional groups (Cl-DOM) are reacting with HOBr by direct bromination leading to Br-CI-DOM and by bromine substitution of chlorine leading to Br-DOM. The latter finding was supported by hexachlorobenzene as a model compound from which bromoform was formed during HOBr treatment. To better understand the experimental findings, a conceptual kinetic model allowing to assess the contribution of each AOBr pathway was developed. A simulation of distribution system conditions with a disinfectant residual of 1 mgC_2 L~(-1) showed complete conversion of Br~- to AOBr, with about 10% of the AOBr formed through chlorine substitution by bromine.
机译：在含溴化物的水进行氯化过程中，预计会形成大量的溴化消毒副产物。这是令人担忧的，因为Br-DBPs通常比其氯化类似物具有更高的毒性。在这项研究中，对含有溶解性有机物（DOM）提取物和溴化物的合成水样品进行了各种消毒处理，以阐明Br-DBP形成的机理。 Br-DBPs的总浓度以可吸附有机溴（AOBr）的形式测量。发现一部分溴（HOBr）通过亲电取代（<40％）与DOM反应，形成AOBr，剩余的HOBr通过电子转移与DOM反应，HOBR还原为溴化物（> 60％）。在手性化过程中，释放的溴化物被氯重新氧化（再循环）为HOBr，导致未改变的DOM位点和氯化的DOM部分进一步发生亲电取代。这导致溴几乎完全掺入DOM（> 87％）。 DOM的类型（3.06≤SUVA_（254）≤4.85）不影响此过程，只要对溴有反应性的DOM位点过多并且可以获得足够的氯暴露即可。当大多数反应性位点被氯消耗时，Cl-取代的官能团（Cl-DOM）通过直接溴化生成Br-CI-DOM和氯的溴取代生成Br-DOM与HOBr反应。后一种发现得到了六氯苯作为模型化合物的支持，在HOBr处理过程中形成了溴仿。为了更好地理解实验结果，开发了一种概念动力学模型，可以评估每个AOBr途径的贡献。消毒残留物为1 mgC_2 L〜（-1）的分配系统条件的模拟表明，Br〜-完全转化为AOBr，其中约10％的AOBr通过溴取代氯形成。

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  • 来源
    《Environmental Science & Technology》 |2017年第9期|5146-5155|共10页
  • 作者

    Markus Langsa; Anna Heitz; Cynthia A. Joll; Urs von Gunten; Sebastien Allard;

  • 作者单位

    Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia ,Jurusan Kimia, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Papua, Manokwari, Papua Barat 98314, Indonesia;

    Department of Civil Engineering, Curtin University, Perth, Western Australia 6845, Australia;

    Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia;

    Eawag, Swiss Federal Institute of Aquatic Science and Technology, ΕΤΗ Zürich, 8092 Zürich, Switzerland ,School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale Lausanne (EPFL), CH-1015 Lausanne, Switzerland;

    Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia;

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