A solvent-responsive robust superwetting titanium dioxide-based metal rubber for oil-water separation and dye degradation

Abstract

The sewage treatment technology of oil-water separation based on superwetting materials has been widely employed. However, the stability of substrates was rarely considered in the past few years, which greatly limited the application of superwetting materials in engineering field. As a new robust, three-dimensional porous material, metal rubber (MR) has attracted significant attention for solving this problem. To treat the wastewater containing insoluble heavy/light oil and soluble dyes, herein, MR capable of degrading organic dyes with switchable wettability and high oil-water separation efficiency was prepared. Firstly, the superhydrophilic MR was obtained by anodizing. Then, the wettability of MR surface was reversibly switched between superhydrophilic and superhydrophobic via alternate immersion in stearic acid ethanol solution and tetrahydrofuran (THF) solvent to achieve switchable oil-water separation of MR. The superwetting MR displayed excellent abrasion resistance and retained outstanding oil-water separation performance after 100 times of sandpaper abrasion. Besides, the surface of pure titanium MR was rich in titanium dioxide (TiO2) after anodic oxidation, which could effectively degrade the organic dyes under ultraviolet light. Therefore, the as-prepared superwetting MR possesses the ability to treat complex wastewater and have applications prospects in controllable oil-water separation and self-cleaning surfaces.