Facile fabrication of 3D hierarchical micro-nanostructure fluorine-free superhydrophobic materials by a simple and low-cost method for efficient separation of oil-water mixture and emulsion

Abstract

In this paper, a simple, environmentally friendly, fluorine-free, economical and effective hydrophobic modification method for melamine sponge (MS) with cobalt oxyhydroxide (CoOOH) and stearic acid (STA) was developed. The 3D pine needle-like hierarchical micro-nanostructure CoOOH coated onto the framework of MS as superhydrophobic materials were successfully constructed and synthesized by low temperature hydrothermal method. By combining the high porosity, superior elasticity, and mechanical stability of the MS with the nanometer scale roughness of CoOOH and low surface energy of STA, the modified CoOOH@STA@MS not only has superhydrophobic surface with the water contact angle of 155°, but also shows outstanding adsorption performance towards the various organic solvents/oils (absorption weight ranging from 20 to 50 times of its own) and excellent recyclability. Additionally, the modified MS can be used as an efficient oil pollutant removal equipment for continuous oil-water separation with the help of peristaltic pump. Furthermore, the CoOOH@STA@MS could be able to separate immiscible oil-water mixture as well as surfactant-stabilized water-in-oil emulsions. All the advantages indicate that the superhydrophobic sponge is the ideal material for oil spills treatment and environmental control.