Green electrospun poly(vinyl alcohol)/silicon dioxide nanofibrous membrane coated with polydopamine in the presence of strong oxidant for effective separation of surfactant-stabilized oil-in-water emulsion

Abstract

Most nanofibrous membranes were electrospun from organic solutions. Because organic solvents are usually volatile and poisonous, they can cause unfavorable influence on the natural environment and human health. In this work, poly(vinyl alcohol)/silicon dioxide@polydopamine (PVA/SiO2@PDA) membrane was fabricated by green electrospinning of aqueous dispersion of PVA and SiO2 combined with deposition of PDA in the presence of strong oxidant sodium periodate. Notably, PDA coating with distinguished superhydrophilic and underwater superoleophobic property was obtained due to producing carboxyl components during degradation of quinone units. When the PVA/SiO2@PDA membrane was immersed in water, a stable hydrated layer produced on the membrane surface due to the presence of hydrophilic groups. The hydrophilicity of this hydrated layer could make water molecules pass through the membrane successfully and effectively prevent infiltration of oil droplets. This superhydrophilic and underwater superoleophobic membrane showed excellent oil/water separation performance for various oil-in-water emulsions. The maximum permeate flux reached 4413.96 L·m−2·h−1 with separation efficiency higher than 99.2 %. Moreover, excellent chemical stability as well as outstanding antifouling performance of the PDA-modified electrospun membrane provided long-term durability for oil/water separation. The developed PVA/SiO2@PDA membrane with superwetting property and good reusability exhibited prospective potential in the remediation of oily wastewater.