Quaternized carbon-based nanoparticles embedded positively charged composite membranes towards efficient removal of cationic small-sized contaminants

Abstract

Abstract This present work validated the feasibility of high-efficient removal of series of cationic small-sized contaminants such as pharmaceutically active compounds (PhACs), dyes and hardness-forming ions in aqueous solution by novel thin-film nanocomposite (TFN) membranes. Thanks to the positively participated effect on interfacial polymerization for both nanostructured quaternized carbon-based nanoparticles (QCBNPs), skin-layer characteristics including smoothness, wettability and positive charge as well as nanoporous loose body (porosity, thickness) of the resultant TFN membranes were all markedly improved after doping modification. On this basis, compared with the neat thin-film composite membrane, these modified TFN membranes showed perfect mirror-symmetric transformation in the rejection orders of the selected electrolytes, dyes and PhACs with different charge properties, respectively. Of course, these changes were all accomplished in the process of increasing each small-sized contaminant removal rate, membrane permeability and fouling resistance. Specifically, the optimal TFN-QCQDs membrane possessed high permeate flux of 23.8\u202fL\u202fm−2·h−1\u202fbar−1, 99.7%, 99.5%, 98.9%, 98.4% and 95.7% rejection rates for cationic trimethoprim, atenolol, rhodamine B, methylene blue and MgCl2, flux recovery ratio of 85.5%, which increased by 53.6%, 6.75%, 5.96%, 2.17%, 2.21%, 17.0% and 29.6%, respectively, compared with the neat membrane. In brief, both QCBNPs embedded nanocomposite membranes provide good alternative options for efficient and sustainable removing series of cationic small-sized contaminants by one step.