Supramolecular micro-nano coating based on strong hydrogen bonding modified filter membrane
In order to solve the problem of poor recyclability of oil/water separation filter membrane,superhydrophilic/underwater superoleophobic tannic acid-polyvinyl alcohol-copper(TA-PVA-CuⅡ)coating modified polyvinylidene fluoride(PVDF)filter membrane(TA-PVA-CuⅡ@PVDF)was synthesized from modification of PVDF membrane with stable micro-nano coating obtained as adhesive of tannic acid-copper(TA-CuⅡ)with supramolecular tannic acid-polyvinyl alcohol(TA-PVA)as adhesive,and characterized by SEM,FTIR and XPS.The surface wettability and oil-water separation performance of PVDF membrane before and after modification were evaluated,while the influence of bivalent copper ion modification time on the reusability of TA-PVA-CuⅡ@PVDF and the durability of the coating were further investigated.The results showed that under the function of hydrophilic micro-nano coating of TA-PVA-CuⅡ,the TA-PVA-CuⅡ@PVDF exhibited a water contact angle of 0° and underwater oil contact angle of 151.0°.In addition,the membrane flux and separation efficiency of TA-PVA-CuⅡ@PVDF about emulsified oil could reach 1169.30 L/(m2·h)and 99.99%,respectively,indicating excellent oil/water separation performance.The TA-PVA-CuⅡ@PVDF modified by CuⅡ for 20 min showed the best recyclability and coating durability with 15 cycles of separation times and a flux change rate of 6.6%.