Partial reduction of graphene oxide toward the facile fabrication of desalination membrane

Developing environmentally friendly and inexpensive membranes for water purifying applications is a global challenge. Graphene oxide is one of the most-studied and tailorable materials for membrane fabrication; however, adjustment of interlayer spacings for an efficient desalination performance has not yet been fully achieved. Herein, graphene oxide was reduced with ascorbic acid for 5–180 min. The partially reduced graphene oxide was utilized through vacuum filtration for membrane preparation. Reduced samples for 5–20 min could form intact membranes, which showed excellent water flux (58–178 L m−2 h−1 bar−1) and efficiently reduced NaCl permeability. Besides, the partially reduced graphene oxides revealed dual interlayer spacings related to almost graphitic domains and semi-reduced domains comprising oxygen-containing functional groups. By investigating the water flow and ion permeation mechanism, the remaining oxidized domains and the major types of functional groups were found to be modulating, respectively. This study showed that partial reduction could be facilely exploited to fabricate graphene oxide-based membranes with adjustable interlayer spacing capable of salt blocking.Graphical Abstract