Polyvinylidene fluoride/boehmite nanocomposite membrane for effective removal of arsenate ion from water

Groundwater arsenic contamination is a serious threat that has affected the health of 130 million people globally. Long-term exposure to arsenic leads to arsenic poisoning, i.e., arsenicosis. Therefore, the development of new technology to reject arsenic from water has been increased. Polyvinylidene fluoride (PVDF) polymer possesses outstanding properties mainly as thermal stability, chemical and mechanical resistance. Boehmite, a polymorphic aluminium oxide, is an essential industrial mineral used as an adsorbent due to its ability to retain high surface area. It has a positive charge, and its surface renders it easy for compounds with negative charges to be attached by electrostatic attraction. Also, the nanoparticles have a high isoelectric value. High adsorption is expected on a higher isoelectric point value. PVDF/boehmite composite membrane was prepared using solvent casting method at room temperature. The nanoparticles were added in Al/As (w/w) ratio of 0:1, 50:1, 200:1 and 500:1. Al/As ratio of 200:1 has shown the best result in batch process, and in static adsorption study, 65% rejection of arsenate ion was achieved from 100 μg/L arsenate solution in 1 h. Flux was calculated in a dead-end filtration setup at 1 bar trans-membrane pressure. The water flux of the membranes was in the range of 62 to 270 L/m2h.