School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulsan, Ulju-gun 689-798, Republic of Korea.
Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85287-5306, United States.
Environ Sci Technol. 2020 Jun 16;54(12):7706-7714. doi: 10.1021/acs.est.0c01846. Epub 2020 Jun 1.
The fouling and cleaning behaviors of -phenylenediamine (MPD), coumarin-3-carboxylic acid (CCA), and d-(+)-glucose (DG) on polyamide nanofiltration (NF) membrane surfaces were investigated with a focus on the two intrinsic equilibrium constants (p) of carboxylic and amine functional groups determined using potentiometric titration. The charged foulants (MPD and CCA) strongly influenced the p of the membrane surface after the fouling layer formed via electrostatic interactions (Virgin = 3.4 and 9.2; MPD-fouled = 4.1 and 8.1; CCA-fouled = 1.5 and 12.4). Moreover, the p of electrostatically fouled membranes substantially recovered when using cleaning agents that released electrostatic interactions (cleaned MPD-fouled = 3.5 and 9.0; cleaned CCA-fouled = 3.3 and 9.6). In contrast, the neutral foulant (DG) did not affect the p (DG-fouled = 3.5 and 9.2); however, the ζ-potential of DG-fouled membrane was closer to zero than the virgin membrane (Virgin = -28.1 mV and DG-fouled = -7.2 mV at pH 7). The p value accurately represented the electrostatic interactions between organic foulants and membrane surfaces. Potentiometric titration is a facile method of determining the p that gives an in-depth understanding of the electrostatic interactions at the membrane surface associated with the membrane fouling and cleaning mechanism.
采用电位滴定法测定了 - 苯二胺（MPD）、香豆素-3-羧酸（CCA）和 d-（+）-葡萄糖（DG）在聚酰胺纳滤（NF）膜表面上的污染和清洗行为，重点研究了通过静电相互作用形成污染层后确定的两个羧酸和胺官能团的固有平衡常数（p）。带电荷的污染物（MPD 和 CCA）通过静电相互作用强烈影响膜表面的 p（Virgin = 3.4 和 9.2；MPD-污染 = 4.1 和 8.1；CCA-污染 = 1.5 和 12.4）。此外，当使用释放静电相互作用的清洁剂清洗静电污染的膜时，p 会大幅恢复（cleaned MPD-fouled = 3.5 和 9.0；cleaned CCA-fouled = 3.3 和 9.6）。相比之下，中性污染物（DG）不会影响 p（DG-污染 = 3.5 和 9.2）；然而，DG-污染膜的 ζ-电位比原始膜更接近零（Virgin = -28.1 mV 和 DG-污染 = -7.2 mV，pH 为 7）。p 值准确地表示了有机污染物与膜表面之间的静电相互作用。电位滴定法是一种测定 p 的简便方法，可以深入了解与膜污染和清洗机制相关的膜表面静电相互作用。
