Han Gang, Liu Jiang Tao, Lu Kang Jia, Chung Tai-Shung
Department of Chemical and Biomolecular Engineering , National University of Singapore , Singapore 117585.
Environ Sci Technol. 2018 Jun 5;52(11):6686-6694. doi: 10.1021/acs.est.7b05933. Epub 2018 May 16.
A facile and versatile approach was demonstrated for the fabrication of low-fouling pressure retarded osmosis (PRO) membranes for osmotic power generation from highly polluted wastewater. A water-soluble zwitterionic random copolymer with superior hydrophilicity and unique chemistry was molecularly designed and synthesized via a single-step free-radical polymerization between 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-aminoethyl methacrylate hydrochloride (AEMA). The P[MPC- co-AEMA] copolymer was then chemically grafted onto the surface of PES/Torlon hollow fibers via amino groups coupling of poly(AEMA) with the polyimide structures of Torlon, leaving the zwitterions of poly(MPC) in the feed solution. Because of the outstanding hydrophilicity, unique cationic and anionic groups, and electrical neutrality of the zwitterionic brush, the newly developed membrane showed great resistances to both inorganic scaling and organic fouling in PRO operations. When using a real wastewater brine comprising multifoulants as the feed, the P[MPC- co-AEMA] modified membrane exhibits a much lower flux decline of 37% at Δ P = 0 bar after 24-h tests and a smaller power density decrease of 28% at Δ P = 15 bar within 12-h tests, compared to 61% and 42% respectively for the unmodified one. In addition to the low fouling tendency, the modified membrane shows outstanding performance stability and fouling reversibility, where the flux is almost fully recovered by physical backwash of water at 15 bar for 0.5 h. This study provides valuable insights and strategies for the design and fabrication of effective antifouling materials and membranes for PRO osmotic power generation.
展示了一种简便且通用的方法，用于制备低污染的压力延迟渗透（PRO）膜，以从高污染废水中产生渗透能。通过2-甲基丙烯酰氧基乙基磷酰胆碱（MPC）和甲基丙烯酸盐酸氨基乙酯（AEMA）之间的一步自由基聚合，分子设计并合成了一种具有优异亲水性和独特化学性质的水溶性两性离子无规共聚物。然后，通过聚（AEMA）的氨基与Torlon的聚酰亚胺结构的偶联，将P[MPC-co-AEMA]共聚物化学接枝到PES/Torlon中空纤维表面，使聚（MPC）的两性离子留在进料溶液中。由于两性离子刷具有出色的亲水性、独特的阳离子和阴离子基团以及电中性，新开发的膜在PRO操作中对无机结垢和有机污染均表现出很强的抗性。当使用包含多种污染物的实际废水盐水作为进料时，与未改性的膜分别为61%和42%相比，P[MPC-co-AEMA]改性膜在24小时测试后，在ΔP = 0 bar时通量下降低得多，为37%；在12小时测试内，在ΔP = 15 bar时功率密度下降较小，为28%。除了低污染倾向外，改性膜还表现出出色的性能稳定性和污染可逆性，通过在15 bar下用0.5小时的水进行物理反冲洗，通量几乎完全恢复。这项研究为设计和制造用于PRO渗透能发电的有效防污材料和膜提供了有价值的见解和策略。
