Arsenic contamination threatens the safety of drinking water in many parts of the world, especially As (Ш), which is more toxic and more difficult to remove than As (Ⅴ). Hence, in terms of environmental protection and sustainable development, it is very important to remove As (Ш) from the environment to reduce the damage to ecosystems and human health. Since there is no effective method for removing As (Ш), it is essential to oxidize As (Ш) into easily removable As (Ⅴ) to achieve effective separation. Herein, a novel copper-coated MnO2 nanowires membrane (Cu@MNM) which combines the oxidation properties of MnO2 and the catalytic and absorption properties of nanoscale Cu (NSCu), was developed based on in situ chemical deposition NSCu on the surface of ultralong MnO2 nanowires. The as-prepared Cu@MNM shows excellent arsenic separation properties with the maximum rejection rate of 96%. The results of pH studies indicate that acidic conditions promote the separation of As (Ш) by Cu@MNM, while alkaline conditions are inhibitory due to deprotonation of Cu@MNM surface enhances electrostatic repulsion. The results of the interfering ions show that the phosphate ions have a strong inhibitory effect on arsenic separation. In addition, Cu@MNM has been shown to be remarkably recyclable and can still achieve a separation efficiency of 60% after five cycles. Therefore, the prepared Cu@MNM with the high arsenic retention efficiency and excellent recycling capabilities has the potential to become an excellent candidate for practical application in arsenic separation.
Keywords: As removal; Cu nanoparticles; Membrane process; Oxidation; Separation mechanism.
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