Enhancing chlorine resistance and water permeance of reverse osmosis membranes by catalytic and photothermal effect

Although various strategies have enhanced the chlorine resistance of polyamide (PA) reverse osmosis (RO) membranes, they cannot simultaneously ensure excellent water permeance and salt rejection. Here, a novel PA RO membrane with hybrid nanoparticles of amino-functionalized carbon quantum dots and nickel oxide (NH 2 -CQDs/NiO@PA) was designed. The catalytic activity of NiO can efficiently decompose free chlorine in water to enhance the chlorine resistance of the membrane. Meanwhile, the photothermal effect of NH 2 -CQDs can increase the surface temperature of the membrane to reduce water viscosity, thereby improving water permeance. In addition, the amino groups of NH 2 -CQDs can increase the density of the PA structure, thereby ensuring salt rejection of the membrane. Under irradiation, the NH 2 -CQDs/NiO@PA membrane exhibits a pure water permeance of 3.69 ± 0.15 L m −2  h −1  bar −1 and a salt rejection of 98.42 ± 0.50%. The salt rejection of the NH 2 -CQDs/NiO@PA and the pure PA membranes, which were subjected to pressurized chlorination with a cumulative chlorine exposure of 3000 ppm·h, is respectively 93.1 ± 1.09% and 70.5 ± 1.73% under irradiation, indicating that the former has higher chlorine resistance. This study provides a feasible strategy for preparing chlorine-resistant PA RO membranes with excellent water permeance and salt rejection.