Synergistic impacts of Cu~(2+) on simultaneous removal of tetracycline and tetracycline resistance genes by PSF/TPU/UiO forward osmosis membrane

摘要

Cu~(2+), tetracycline (TC), and corresponding tetracycline resistance genes (TRGs) are common micropollutants in aquaculture wastewater, which have great impact on environment and human health. In this study, we developed a thin-film nanocomposite (TFN) forward osmosis (FO) membrane with an electrospinning thermoplastic polyurethane/polysulfone (PSF/TPU) substrate and a UiO-66-NH_2 particle interlayer modified active layer. The effects of Cu~(2+) concentration on the synergetic removal of TC and TRGs (e.g., tetA/M/X/O/C, int1, and 16 S rRNA gene) were analyzed to determine the role of Cu~(2+) in FO process. The rejection mechanism was also analyzed in depth. Results demonstrated that the rejection of TC and Cu~(2+) was 99.53% and 97.99%. The rejection of TRGs exceeded 90% (specifically, over 99% for tetC) at a Cu~(2+) concentration of 500 μg/L when 0.5 M (NH_4)_2HPO_4 was used as draw solution. Complexation reaction between Cu~(2+) and TC, electrostatic interaction, and the adsorption of Cu~(2+) on membrane surface were the main contributing factors for the high rejection efficiencies. Altogether, the as-prepared FO membrane holds great potential for simultaneously removing heavy metals, antibiotics, and resistance genes in real wastewater.