Ding Chunxiao, Qi Hong
College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, China.
Membranes (Basel). 2023 May 22;13(5):536. doi: 10.3390/membranes13050536.
Pristine graphene oxide (GO)-based membranes have proven promising for molecular and ion separation owing to efficient molecular transport nanochannels, but their separation ability in an aqueous environment is limited by the natural swelling tendency of GO. To obtain a novel membrane with anti-swelling behavior and remarkable desalination capability, we used the AlO tubular membrane with an average pore size of 20 nm as the substrate and fabricated several GO nanofiltration ceramic membranes with different interlayer structures and surface charges by fine-tuning the pH of the GO-EDA membrane-forming suspension (pH = 7, 9, 11). The resultant membranes could maintain desalination stability, whether immersed in water for 680 h or operated under a high-pressure environment. When the pH of the membrane-forming suspension was 11, the prepared GE-11 membrane showed a rejection of 91.5% (measured at 5 bar) towards 1 mM NaSO after soaking in water for 680 h. An increase in the transmembrane pressure to 20 bar resulted in an increase in the rejection towards the 1 mM NaSO solution to 96.3%, and an increase in the permeance to 3.7 L·m·h·bar. The proposed strategy in varying charge repulsion is beneficial to the future development of GO-derived nanofiltration ceramic membranes.
由于具有高效的分子传输纳米通道,原始氧化石墨烯(GO)基膜在分子和离子分离方面已被证明具有潜力,但其在水环境中的分离能力受到GO自然膨胀趋势的限制。为了获得一种具有抗膨胀性能和卓越脱盐能力的新型膜,我们使用平均孔径为20nm的AlO管状膜作为基底,并通过微调GO-EDA成膜悬浮液的pH值(pH = 7、9、11)制备了几种具有不同层间结构和表面电荷的GO纳滤陶瓷膜。所得的膜无论是在水中浸泡680小时还是在高压环境下运行,都能保持脱盐稳定性。当成膜悬浮液的pH值为11时,制备的GE-11膜在水中浸泡680小时后,对1mM NaSO的截留率为91.5%(在5巴下测量)。跨膜压力增加到20巴时,对1mM NaSO溶液的截留率增加到96.3%,通量增加到3.7 L·m·h·bar。所提出的改变电荷排斥的策略有利于GO衍生的纳滤陶瓷膜的未来发展。