A robust air superhydrophilic/superoleophobic diatomite porous ceramic for high-performance continuous separation of oil-in-water emulsion

Three-dimensional (3D) porous architecture has attracted considerable attention in remediation of oil/water emulsion. In present work, an air superhydrophilic/superoleophobic diatomite porous ceramic (AS-DC) was prepared, using SiO2 whiskers modified diatomite ceramic as the substrate and FS-50 as the modifier. The interconnected SiO2 whiskers intertwined on the skeleton of ceramic block forming a 3D network structure, which not only improved the wettability of AS-DC, but also reinforced its mechanical property (about 2.5 MPa of compressive strength). The as-prepared AS-DC with intrinsically superoleophobicity (154°) and superhydrophilicity (0°) exhibited an underwater oil contact angle of 161°, suggesting a multifunctional separation capability. By simply assembling AS-DC with pipes and a pump, it could not only separate the surfactant-stabilized oil-in-water emulsion in a permeation flux as high as 107.8 kg min-1 m-2 with a selectivity of >95%, but also collect the clean water from the floating oil/water mixture in a flux of 197.4 kg min-1 m-2 and a selectivity of ∼99%. In addition, the AS-DC was resistant to the salt/acid/alkaline corrosion and temperature fluctuation. The mechanical/chemical firmness of AS-DC renders it tremendous potential as a robust 3D architecture in real application for purification of oil/water mixture.