Fig. 8: Comparative performance studies of fabricated membranes.

a Pure water permeability; b Representation of electrostatic repulsion mechanism between the surface of CQACNT composite membrane and metal ions; c Metal ion removal performance of the prepared membranes; d Effect of Zn2+ concentration on the removal efficiency of CQACNT-0 and CQACNT-6 membranes. Error bars represent the standard deviation between three reported values.