School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Environ Sci Technol. 2021 Mar 2;55(5):3352-3361. doi: 10.1021/acs.est.0c08101. Epub 2021 Feb 17.
Domestic wastewater is a valuable reservoir of nutrients such as nitrogen and phosphorus. However, the presence of emerging micropollutants (EMPs) hinders its applications in resource recovery. In this study, we designed and fabricated a novel thin-film composite polyamide membrane, which enables highly selective nanofiltration (NF) that removes EMPs effectively while preserving valuable nutrients in the permeate. By incorporating polyethylenimine as an additional monomer to piperazine and surfactant sodium dodecyl sulfate in interfacial polymerization, we precisely tuned membrane pore size, pore size distribution, and surface charge. The resultant NF membrane achieved desirable solute-solute selectivity between EMPs (rejection rate > 75%) and nutrient N and P ions (rejection rate < 25%). By applying a modified Donnan steric pore model with dielectric exclusion, which takes membrane pore size distribution into consideration, we demonstrate the synergistic effect of membrane pore size, pore size distribution, and surface charge in regulating membrane solute-solute selectivity. Designing solute-solute selective NF membranes for fit-for-purpose wastewater treatment has great potential to improve the flexibility of membrane technologies that can convert wastewater streams to valuable water and nutrient resources.
生活污水是氮、磷等营养物质的重要储存库。然而，新兴的微量污染物 (EMP) 的存在阻碍了其在资源回收中的应用。在本研究中，我们设计并制造了一种新型的薄膜复合聚酰胺膜，该膜能够实现高效的纳滤 (NF)，有效去除 EMP，同时保留透过物中的有价值营养物质。通过将聚乙烯亚胺作为哌嗪和表面活性剂十二烷基硫酸钠的附加单体加入到界面聚合中，我们精确地调节了膜孔径、孔径分布和表面电荷。所得的 NF 膜在 EMP（截留率>75%）和营养 N 和 P 离子（截留率<25%）之间实现了理想的溶质-溶质选择性。通过应用考虑到膜孔径分布的改良的 Donnan 空间位阻模型，我们证明了膜孔径、孔径分布和表面电荷在调节膜溶质-溶质选择性方面的协同作用。设计用于特定用途的污水的溶质选择性 NF 膜，对于提高膜技术的灵活性具有巨大的潜力，膜技术可以将污水转化为有价值的水和营养资源。
