Effect of coexisting metal ions on the degradation of polyamide reverse osmosis membrane by hypochlorite treatment
Effect of coexisting metal ions on the degradation of polyamide reverse osmosis membrane by hypochlorite treatment
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DOI：
10.1016/j.desal.2015.12.005
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发表时间：
2016-03
期刊：
影响因子：
9.9
通讯作者：
Masaki Ohno;Cervinia V. Manalo;L. Rossetto;T. Okuda;S. Nakai;W. Nishijima
中科院分区：
文献类型：
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作者：
Masaki Ohno;Cervinia V. Manalo;L. Rossetto;T. Okuda;S. Nakai;W. Nishijima
评估了共存金属离子对次氯酸盐降解聚酰胺（PA）反渗透膜的加速作用。还研究了金属离子的加速机制。次氯酸盐加速膜降解是由本研究中使用的所有一价和二价金属离子引起的：Na+、K+、Ca2+、Mg2+ 和 Ba2+。显示了二价金属离子在 PA 膜降解中的效力，因为二价金属离子的浓度比一价金属离子低得多，导致膜降解。 Na+ 在浓度低于 100 mM 时不会加速 PA 膜的降解，而 Mg2+ 和 Ca2+ 则没有显示阈值限制。在单价和二价金属离子存在的情况下加速膜降解似乎受到存在的每种离子的浓度范围内单价离子的阈值限制的影响。低于阈值限制的膜降解主要由二价离子主导，而高于阈值限制的膜降解主要由单价离子主导。有或没有金属离子的PA膜的降解机理是相同的。然而，在二价离子存在的情况下，它可能在酰胺水解中充当催化剂，导致加速膜降解。
Accelerating effect of coexisting metal ions on the polyamide (PA) reverse osmosis membrane degradation by hypochlorite was evaluated. The acceleration mechanism by the metal ions was also examined. The acceleration of membrane degradation by hypochlorite was caused by all monovalent and divalent metal ions used in this study: Na+, K+, Ca2 +, Mg2 +, and Ba2 +. Potency of divalent metal ions in PA membrane degradation was shown since divalent ions in much lower concentration than the monovalent metal ions caused membrane degradation. Na+did not accelerate the degradation of the PA membrane in concentrations less than 100 mM while Mg2 +and Ca2 +showed no threshold limits. Accelerated membrane degradation in the presence of both monovalent and divalent metal ions seemed to be influenced by the threshold limit of the monovalent ion within the concentration range of each of the ions present. Membrane degradation below the threshold limit is dominated by the divalent ion while above the threshold limit the monovalent ion dominated the degradation. The degradation mechanism of PA membranes with or without metal ions is the same. However, in the presence of the divalent ion, it possibly acts as a catalyst in the amide hydrolysis, leading to accelerated membrane degradation.