Spraying-induced in situ growth of CaCO3 for the modification of membranes for oil/water separation

Abstract

Here, a simple spraying-induced in situ growth of inorganic particles strategy was adopted to fabricate composite membranes. Sodium alginate was first sprayed on a polyvinylidene fluoride membrane to provide active sites, and subsequently, alternate spraying of Ca²⁺ and CO₃²⁻ induced in situ growth of CaCO₃ particles to construct hierarchical structures. The optimal membrane exhibited superhydrophilicity/underwater superoleophobicity. The membrane has good oil–water separation efficiency (>99%) and high flux (>2238 L m⁻² h⁻¹) for several oil–water emulsions. Importantly, the membrane retained acceptable separation performance even after 10 cycles, proving its good mechanical stability and anti-fouling features. The current work may open up a new avenue for the large-scale fabrication of super-wetting membranes for oily wastewater remediation.