Photocatalytic self-cleaning carbon nitride nanotube intercalated reduced graphene oxide membranes for enhanced water purification

Crumpled laminar nanostructures with nanoscale water transport channels constructed by two-dimensional (2D) reduced graphene oxide nanosheets (rGO NS) have been considered as a promising membrane separation layer for water purification. However, efficient tuning of rGO laminar structures with enhanced membrane performance remains challenging. In this work, we report a novel 1D graphitic carbon nitride nanotube (g-C3N4 NT) intercalated rGO nanofiltration (NF) membrane with enhanced photo-induced self-cleaning performance. The g-C3N4 NT photocatalyst could not only enlarge the rGO interlayer spacing for improved water permeability, but also endow the composite membrane with visible-light photocatalytic activity for efficient removal of organic dyes from polluted water. Our g-C3N4 NT/rGO membrane exhibits superior water permeability (4.87 L·m−2·h−1·bar−1) and synergetic Rhodamine B (RhB) removal rate (>98%) for long-term operation, compared with pristine rGO membrane and 2D g-C3N4 NS intercalated rGO membrane prepared by the same method. The RhB removal mechanism on the as-prepared composite membranes under integrated photocatalytic filtration process is presented. Our findings offer new insights into designing and tuning laminar structures of photocatalytic graphene-based NF membranes for enhanced water purification.