Fabrication of calcium carbonate coated-stainless steel mesh for efficient oil-water separation via bacterially induced biomineralization technique

Abstract

Creating an environmentally friendly and energy-efficient strategy to fabricate oil-water separation materials for dealing with oil spill remains a great challenge. Herein, we presented a superhydrophobic calcium carbonate (CaCO3) coated-stainless steel mesh (SSM) fabricated using a bacterially induced biomineralization technique and subsequent surface modification with stearic acid (SA). In the presence of Bacillus subtilis, a commonly existing bacterium in soil and sea, a continuous, dense, and thick CaCO3 coating could be formed on the SSM surface based on the biomineralization effect, forming the superhydrophilic mesh (CaCO3-SSM). The superhydrophilic CaCO3-SSM was then modified by the SA to obtain the superhydrophobic mesh (SA/CaCO3-SSM). The SA/CaCO3-SSM showed high oil fluxes (0.2–9.12 × 104 L·m−2·h−1) and high separation efficiencies (>94.8%) for various oil/water mixtures. Furthermore, the SA/CaCO3-SSM demonstrated ideal wear resistance, outstanding anti-pollution performance, and promising anti-icing characteristic, endowing it with the capability to work under harsh environments. This study provides an inexpensive, environmental-friendly, and pollution-free method to construct superhydrophilic or superhydrophobic surfaces and opens a new avenue for the fabrication of oil-water separation meshes with multifunctionality.