Efficient removal of As(III) by Cu nanoparticles intercalated in carbon nanotube membranes for drinking water treatment
Résumé
Arsenic contamination is threatening drinking water safety in many areas around the world. Among different
arsenic species in water, arsenite or As(III) is the most difficult one to remove due to its neutrality in drinking
water. Therefore, development of novel materials is warranted for efficient As(III) removal. Herein, novel nanocomposite
materials were facilely prepared by intercalating Cu nanoparticles into carboxylated/hydroxylated
carbon nanotubes (CNT) deposited on top of a conventional polymeric membrane. The as-prepared membrane
possessed high pure water permeability (4639–4854 Lm−2 h−1 bar−1) and capability to remove more than 90%
of As(III) at transmembrane pressures below 0.01 bar, which is plausible for gravity-driven membrane (GDM)
filtration applications. Compared to Fe-based materials reported in the literature, the Cu/CNT nanocomposite
membranes exhibited robustness in removing As(III) at a pH range of 5–9 and in the presence of chloride, nitrate,
bicarbonate, sulfate and natural organic matter. A mechanical investigation suggests that the filtration process
involves direct adsorption of As(III) onto Cu/CNT composites. As(V) species were also produced due to oxidation
of As(III) by dissolved oxygen under the catalysis of Cu and adsorbed by Cu/CNT composites. Overall, the novel
Cu/CNT nanocomposite membranes exhibit promising potentials in As(III) removal from contaminated water,
and are worth of further investigation for their suitability in drinking water treatment.