Enhanced separation performance of carbon nanotube-polyvinyl alcohol composite membranes for emulsified oily wastewater treatment under electrical assistance
Enhanced separation performance of carbon nanotube-polyvinyl alcohol composite membranes for emulsified oily wastewater treatment under electrical assistance
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电辅助下碳纳米管-聚乙烯醇复合膜增强乳化含油废水分离性能
DOI：
10.1016/j.seppur.2017.12.058
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发表时间：
2018
影响因子：
8.6
通讯作者：
Yu Hongtao
中科院分区：
文献类型：
--
作者：
Yi Gang;Chen Shuo;Quan Xie;Wei Gaoliang;Fan Xinfei;Yu Hongtao
膜技术是处理乳化油废水的有效方法，但膜存在渗透性和选择性的矛盾以及严重的膜污染。本研究制备了具有高水通量和良好导电性能的碳纳米管-聚乙烯醇（CNT-PVA）复合膜，并将其作为阴极用于正十六烷水乳化液（n-emulsion）和切削液乳化液（c-emulsion）的过滤，以提高除油效率和减轻膜污染。结果表明，在-1.5V电压下，正乳化液的除油率从85.2%提高到97.6%，丙乳化液的除油率从56.7%提高到83.0%。在-1.5 V电压下运行60 min后的渗透通量分别是无乳化电位和无乳化电位时的2.3倍和2.2倍。此外，从膜表面的SEM图像可以观察到较少的油污染，根据污染模型的分析可以减轻污染。循环伏安法和zeta电位分析表明，静电斥力，而不是电化学反应是负责提高石油去除率和过滤过程中的可渗透性。5次连续运行的长期过滤结果表明，在膜上施加电位，在高除油率和高通量恢复率方面保持了显著的稳定性。
Membranes provide an effective solution to treat emulsified oily wastewater, but usually have inherent drawbacks: permeability and selectivity trade-off as well as serious membrane fouling. In this study, carbon nanotube-polyvinyl alcohol (CNT-PVA) composite membranes with high water flux and good electrical conductivity were fabricated and then served as cathode during the filtration ofn-hexadecane-in-water emulsion (n-emulsion) and cutting fluid emulsion (c-emulsion) to improve the oil removal efficiency and alleviate membrane fouling. Results show that oil removal rates increase from 85.2% to 97.6% forn-emulsion and from 56.7% to 83.0% for c-emulsion after the application of −1.5 V. The permeation flux after an operation of 60 min with −1.5 V are 2.3 times and 2.2 times of those without potential forn-emulsion and c-emulsion, respectively. Additionally, less oil fouling can be observed from the SEM images of the membrane surface and fouling can be mitigated according to the analysis of fouling model. Cyclic voltammetry and zeta potential analysis demonstrate that electrostatic repulsion rather than electrochemical reactions is responsible for the enhanced oil removal rate and antifouling ability in the filtration process. Furthermore, the results of long term filtration with five runs indicate that the application of potential onto the membranes maintains remarkable stability in high oil removal rate and high flux recovery rate.