Bioadhesion-inspired surface engineering constructing robust, hydrophilic membranes for highly-efficient wastewater remediation

Abstract

The membrane separation technique can strongly advance the energy-efficient water remediation due to its low cost and small footprint. However, the inherent hydrophobicity of most polymeric membrane materials limits the water-treatment efficiency, which urgently requires to develop surface hydrophilization engineering on hydrophobic polymeric membranes. Inspired by the structure/function characteristics of robust mussel/tunicate adhesive proteins, a one-step, eco-friendly, and cost-effective biomimetic coating system was designed and utilized to realize membrane surface hydrophilization via the intermolecular “amino/mercapto-pyrogallol bridges”. The as-coated poly(vinylidene fluoride) micro-/ultra-filtration (MF/UF) membranes exhibited greatly enhanced wettability, good harsh condition tolerance, high filtration efficiency, and excellent fouling resistance. Both of emulsified oily and simulated protein wastewater were remediated accordingly. The optimal MF membrane demonstrated a pure water flux as high as ca. 7900 L m−2 h−1 (47 times higher regarding the pristine membrane), and oil rejection efficiency beyond ca. 99.5% during the cycling emulsion filtration tests. The coated UF membrane possessed a benign protein interception efficiency (BSA rejection of ca. 95.4% with water flux of ca. 400.7 L m−2 h−1) and greatly enhanced fouling resistance (78.0% increment). The new biomimetic synergistic coating strategy can promote the rapid development of advanced membranes via elegant surface manipulation towards water-energy nexus.