Graphene Oxide-palygorskite Composite Membrane with Sub-Nanometer Channels for Efficient Rejection of NaCl, Heavy Metal Ions, and Dyes

Graphene oxide (GO) has attracted significant attention in the field of wastewater treatment due to its numerous advantages, such as high porosity, nanoscale wrinkles, and interlayer channels. However, there are still challenges in preparing GO-based composite membranes with sub1nano-channels through a feasible strategy for effectively removing NaCl, heavy metal ions, and dyes. Here, a novel GO-based composite membrane with a sub-1 nanochannel was successfully fabricated by controlling the intercalation of different amounts of palygorskite (PAL). The engineered connection between the GO nanosheets and PAL via coordination bonds resulted in a membrane that demonstrated exceptional retention capabilities and permeation flux. By carefully regulating the coordination ratio between PAL and the GO matrix, we were able to create sub-1 nm apertures that facilitate selective transportation of water while effectively rejecting contaminants. The resulting membrane demonstrates high retention rates of 78.1% for NaCl, 99.2% for anionic dye rejection, and ≥87% for heavy metal ion rejection. The unique performance of this GO-PAL composite membrane makes it a promising candidate for addressing the challenges associated with the removal of various contaminants from wastewater.