Modeling arsenic (V) removal from water by micellar enhanced ultrafiltration in the presence of competing anions
Modeling arsenic (V) removal from water by micellar enhanced ultrafiltration in the presence of competing anions
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DOI：
10.1016/j.chemosphere.2018.09.046
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发表时间：
2018-12-01
期刊：
影响因子：
8.8
通讯作者：
Peltier, Edward
中科院分区：
文献类型：
--
作者：
Chen, Ming;Shafer-Peltier, Karen;Peltier, Edward
随着世界各地砷(As)污染事件的报道越来越多，为了保护饮用水水源，需要更好的工艺来去除工业废水和其他受污染的水中的砷。十六烷基吡啶(CPC)阳离子表面活性剂胶束与As的络合结合超滤(UF)有可能提高As的去除效果，但来自其他阴离子的竞争可能是一个限制因素。用二元体系离子交换模型测定了As(V)与阳离子十六烷基吡啶(CP+)胶束结合的选择性系数，对H_2AsO_4~-的选择性系数为0.047·55，对HAsO_4~(2-)的选择性系数为0.047摩尔·L~(-1)。Cp+胶束与常见单价阴离子结合的亲和顺序为NO3-&Gt；Cl-&Gt；HCO3-&Gt；HAsO4-；对于二价阴离子，亲和顺序为SO42-&Gt；HAsOi-。用离子交换等温线研究了As(V)在胶束和水相之间的分配，较高的pH和较低的竞争阴离子浓度增加了As(V)在UF膜上的截留率。基于跨超滤膜的质量平衡和阴离子与CP+胶束结合的选择性系数，建立了一个考虑这些影响的模型，用于预测胶束增强超滤(MEUF)过程中竞争阴离子混合物的As(V)去除。对人工河水和天然河水样品的模型预测与实验结果吻合较好。在超滤前投加20 mM的CPC，人工水和掺入天然河水中的砷(约0.1 mm)的去除效果分别达到91%和84%。(C)2018爱思唯尔有限公司。保留所有权利。
With increasing arsenic (As) contamination incidents reported around the world, better processes for As removal from industrial wastewater and other contaminated waters are required to protect drinking water sources. Complexation of As with cetylpyridinium chloride (CPC) cationic surfactant micelles, coupled with ultrafiltration (UF), has the potential to improve As removal, but competition from other anions could be a limiting factor. Using a binary-system ion-exchange model, the selectivity coefficients for binding of the monovalent and divalent forms of arsenate (As (V)) to cationic cetylpyridinium (CP+) micelles, relative to Cl-, were determined to be 0.55 for H2AsO4- and 0.047 mol L-1 for HAsO42-, respectively. The affinity sequence for binding of commonly occurring monovalent anions by CP+ micelles was found to be NO3- > Cl- > HCO3- > H2AsO4-, and for divalent anions, SO42- > HAsOi-. Distribution of As (V) between the micellar and aqueous phases was explored using ion exchange isotherms, with higher pH and lower concentrations of competing anions increasing rejection of As (V) across UF membranes. A model accounting for these effects, based on mass balances across UF membranes and selectivity coefficients for binding of anions to the CP+ micelles, was used to predict As (V) removal during micellar-enhanced ultrafiltration (MEUF) of mixtures of competing anions. Model predictions agreed well with experiment results for both artificial and spiked natural river water samples. Arsenic (approximate to 0.1 mM) removals of 91% and 84% were achieved from artificial waters and spiked natural river waters, respectively, by adding 20 mM CPC prior to UF. (C) 2018 Elsevier Ltd. All rights reserved.