Zhuang Pengyu, Guo Zhongya, Wang Shuang, Zhang Qi, Zhang Mingjian, Fu Lili, Min Han, Li Bin, Zhang Ke
Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450001, China.
Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
ACS Omega. 2021 Nov 3;6(45):30656-30665. doi: 10.1021/acsomega.1c04466. eCollection 2021 Nov 16.
Energy-saving membrane separation for water purification is increasingly desired, which requires appropriate nanofiltration membranes enabling to reject undesired solutes efficiently and allows high permeation of water. Herein, we report the fabrication of three-dimensional lamellar reduced graphene oxide (rGO) hydrogel membranes with a one-step, environment-friendly and water/vapor interfacial hydrothermal assembly process and the corresponding aerogel membranes by the freeze-drying method. The structures of the aerogel membranes can be tuned from lamellar to porously interconnected morphologies by controlling the volume of GO suspensions during the hydrothermal process. The rGO aerogel membrane was extremely flexible, which can be bent in liquid nitrogen and boiling water without any deformation, and highly stable in various solvents for at least 2 months. When used as nanofiltration membranes, the rGO aerogel membranes showed ∼100% rejection of organic dyes and a moderate water flux (up to 53 L m h) only under the gravity of organic dye aqueous solutions of a 30 cm height. This water self-purification property of our flexible and stable aerogel membranes without extra energy consumption provides a possibility to make cheap, portable water purification devices for utilization in emergency and home-used water purification systems in the areas with electricity unavailable or inconvenient.
用于水净化的节能膜分离技术的需求日益增长，这需要合适的纳滤膜能够有效地截留不需要的溶质并允许水的高渗透性。在此，我们报道了通过一步法、环境友好的水/蒸汽界面水热组装工艺制备三维层状还原氧化石墨烯（rGO）水凝胶膜以及通过冷冻干燥法制备相应的气凝胶膜。通过在水热过程中控制氧化石墨烯悬浮液的体积，可以将气凝胶膜的结构从层状调整为多孔互连形态。rGO气凝胶膜极具柔韧性，可在液氮和沸水中弯曲而无任何变形，并且在各种溶剂中高度稳定至少2个月。当用作纳滤膜时，rGO气凝胶膜仅在30厘米高的有机染料水溶液重力作用下对有机染料的截留率约为100%，水通量适中（高达53 L m⁻² h⁻¹）。我们的柔性且稳定的气凝胶膜的这种水自净化特性无需额外能耗，为制造廉价、便携式水净化设备提供了可能性，可用于电力供应不可用或不便地区的应急和家用净水系统。
