Efficiencies and mechanisms of chemical cleaning agents for nanofiltration membranes used in produced wastewater desalination
Efficiencies and mechanisms of chemical cleaning agents for nanofiltration membranes used in produced wastewater desalination
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产废水淡化纳滤膜化学清洗剂的效率和机理
DOI：
10.1016/j.scitotenv.2018.10.221
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发表时间：
2019
影响因子：
9.8
通讯作者：
Liu Guicai
中科院分区：
文献类型：
--
作者：
Zhao Dongsheng;Qiu Liping;Song Jiyu;Liu Junxia;Wang Zonghua;Zhu Youbing;Liu Guicai
一个螺旋缠绕的纳滤（NF）膜组件收获的全面生产废水脱盐厂进行了检查和清洗，以探索适当的化学清洗协议。研究了污垢的识别和清洗效率及机理。对于总污垢，有机组分，包括阴离子聚丙烯酰胺（APAM）和原油，占86.3%的重量百分比，而其余污垢构成的无机部分，包括钠，镁，钙，钡，铝，铁和硅。设计了短期清洁实验，以确定有效的试剂，可用于进一步评价其在长期清洁中的清洁效率。对于柠檬酸和乙二胺四乙酸四钠（EDTA-4 Na），长期清洁效率相对较低甚至为负，而所述值随不同的表面活性剂而变化。十二烷基三甲基氯化铵（DTAC）实现了最大的通量恢复;相反，十六烷基三甲基氯化铵（CTAC）提供微不足道的，甚至是负面的影响，通量恢复，以及作为盐排斥，污染纳滤膜。污染膜的FTIR和Zeta电位分析表明，所有测试的表面活性剂在从膜表面去除污垢方面都是同样有效的，但它们的清洁效率不同。此外，通量比（Sf）和渗透液中的表面活性剂浓度（Cps）之间的强相关性进行了观察。在所测试的化学试剂中，DTAC产生最高的Cp和最大的通量恢复，具有2.25的Sf。考虑到这种相关性和污染的膜和表面活性剂的特性，提出DTAC分子渗透膜孔并去除附着在孔壁上的污垢。
A spiral-wound nanofiltration (NF) membrane module harvested from a full-scale produced wastewater desalination plant was examined and cleaned to explore appropriate chemical cleaning protocols. Foulant identification and cleaning efficiency and mechanisms were investigated. For total foulants, the organic components, including anionic polyacrylamide (APAM) and crude oil, accounted for a weight percentage of 86.3%, while the remaining foulants constituted the inorganic fraction, including Na, Mg, Ca, Ba, Al, Fe and Si. Short-term cleaning experiments were designed to identify effective reagents that could be used for further evaluations of their cleaning efficiencies in long-term cleaning. For citric acid and ethylenediaminetetraacetic acid tetrasodium (EDTA-4Na), the long-term cleaning efficiencies were relatively slight or even negative, while said values varied with different surfactants. Dodecyltrimethylammonium chloride (DTAC) achieved the greatest flux recovery; conversely, cetyltrimethylammonium chloride (CTAC) provided insignificant, even negative effects, on flux recovery, as well as salt rejection, of the fouled NF membranes. FTIR and zeta potential analyses of the fouled membranes indicated that all the tested surfactants were identically effective in removing the foulants from the membrane surface, but their cleaning efficiencies differed. Moreover, a strong correlation between the flux ratio (Sf) and concentration of surfactant in the permeate (Cps) was observed. Among the tested chemical reagents, DTAC yielded the highest Cpsand the greatest flux recovery, with an Sfof 2.25. Considering this correlation and the characteristics of the fouled membranes and surfactants, it is proposed that DTAC molecules penetrated the membrane pores and removed the foulants that were attached to the pore walls.