Robust Nacrelike Graphene Oxide–Calcium Carbonate Hybrid Mesh with Underwater Superoleophobic Property for Highly Efficient Oil/Water Separation

Abstract

Inspired by the mastoid structure of the lotus leaf and the robust layered structure of the nacre, a novel nacrelike graphene oxide-calcium carbonate (GO-CaCO₃) hybrid mesh with superhydrophilic and underwater superoleophobic property was prepared for the first time, via a facile, economical, and environmentally friendly layer-by-layer (LBL) self-assembly method using commercially available stainless steel mesh (SSM) as a ready-made mask. Interestingly, GO nanosheets played a threefold role, regulating the growth of CaCO₃ nanocrystals between the GO interlamination for constructing a "brick-and-mortar" structure, improving the interface stability via coordination assembly onto SSM, and creating strong hydration derived from rich oxygen-containing functional groups. The surface hydrophilicity and hierarchically micro/nanoscale structure of GO-CaCO₃ artificial pearls imbed on the SSM, contributing to outstanding superhydrophilicity and underwater superoleophobicity. The biomimetic hybrid mesh exhibited a strong mechanical property with a Young's modulus of 25.4 ± 2.6 GPa. The optimized hybrid mesh showed a high separation efficiency of more than 99% toward a series of oil/water mixtures with high flux. The low oil-adhesion force, high fatigue-resistance, chemical stability (acid/alkali/salt resistance), and excellent recycling performance enlighten the great prospects of GO-based nacrelike material for application in oily wastewater treatment.