Toward Enhancing the Chlorine Resistance of Reverse Osmosis Membranes: An Effective Strategy via an End-capping Technology
Toward Enhancing the Chlorine Resistance of Reverse Osmosis Membranes: An Effective Strategy via an End-capping Technology
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增强反渗透膜的耐氯性：通过封端技术的有效策略
DOI：
10.1021/acs.est.8b06006
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发表时间：
2019
影响因子：
11.4
通讯作者：
Zhang Xuan
中科院分区：
文献类型：
--
作者：
Yao Yujian;Zhang Wen;Du Yexin;Li Meng;Wang Lianjun;Zhang Xuan
聚酰胺反渗透(RO)膜由于其独特的化学结构，在暴露在游离氯中时会出现性能衰退。腐烂限制了它们的寿命，增加了运营成本。本文首次采用二次界面聚合法，以间苯二甲酰氯(IPC)为封端试剂，消除了未反应氨基与氯相互作用时的负面影响。所制备的膜的表面Zeta电位在较宽的pH范围内几乎保持不变，这很大程度上证明了封端过程的高转化率。然而，无论是表面形态还是分离性能都没有明显的影响。由于聚酰胺层中没有端氨基，IPC改性膜的耐氯性显著提高，特别是在高pH值下。当总氯气曝露量接近10 000ppm·h时，膜的脱盐性能保持不变，而在相同条件下，未改性膜只截留了80.3%的氯化钠。这种SIP技术可以直接应用于商用SW30海水淡化膜，使其对游离氯的耐受性更强。总体而言，我们的结果有力地证明了IPC辅助端盖工艺是一种有前途的、可行的、可扩展的提高反渗透膜抗氯气性的技术。
Polyamide reverse osmosis (RO) membranes suffer performance decay when exposed to free chlorine because of their unique chemical structure. The decay limits their lifespan and increases operating cost. Herein, the secondary interfacial polymerization method was performed, for the first time, using isophthaloyl chloride (IPC) as the chain-terminating reagent, to eliminate the negative effect when the unreacted amino groups interact with chlorine. The surface zeta potential of the as-prepared membrane remained almost constant over a wide pH range, which greatly demonstrated the high conversion ratio of the end-capping procedure. However, neither the surface morphology nor the separation properties were conspicuously influenced. Because of the absence of the terminated amino groups in the polyamide layer, the IPC-modified membrane exhibited significantly improved chlorine resistance, particularly at high pH. Its desalination performance remained unchanged as the total chlorine exposure approached 10 000 ppm·h, whereas only 80.3% of the NaCl was rejected by the unmodified membrane under the same conditions. Such SIP technology can be applied directly to the commercial SW30 seawater desalination membrane, making it more tolerant to free chlorine. Overall, our results strongly proved the IPC-assisted end-capping process as a promising, practicable, and scalable technology for enhancing the chlorine resistance of an RO membrane.