Advanced super-wetting biaxial polypropylene membrane with hierarchical rough surface for multipollutant removal from oily wastewater

Abstract

The hazardous toxicity of oily wastewater creates a negative impact on the environment and ecosystem that has made water separation an open challenge on a global scale. A promising and workable tactic to prevent contaminations and effective water separation from oily wastewater has been proved using cutting-edge advanced polymeric membrane-based separation technology. Excessive hydrophobicity, contamination vulnerability, and membrane fouling are recurring and crippling problems for the treatment of oily wastewater. To overcome these difficulties, we design a facile, scalable, and highly efficient layer-by-layer modification technique using polyethylene imine and levo-3,4 dihydroxyphenylalanine cross-linked multi-layer assembled rough biaxial polypropylene membrane surface. The synergistic development of the rough surfaces causes the embeddedness of wetting properties of the modified membrane with excellent superhydrophilicity (0º) and underwater superoleophobicity (∼164.3º). Such great underwater superoleophobicity shows a superior oil-repulsive property that helps to achieve high separation efficiency (99.9 %) and permeate flux (2325.3 L m−2 h−1). Additionally, our modified membrane holds excellent anti-bacterial properties against S. aureus and E. coli bacteria with 92.8 % and 88.6 % viability, respectively. Notably, this highly efficient modified membrane is capable of removing multi pollutants (oil particles and bacteria) from oily wastewater in a more energy-efficient way.