Robust and durable superhydrophobic and oil-absorbent silica particles with ultrahigh separation efficiency and recyclability

With the continuous occurrence of oil-spill accidents, superhydrophobic materials demonstrate tremendous potential in oil-water separation. In this research work, SiO2 nanospheres with surface mercapto groups were prepared by the condensation reaction of 3-mercaptopropyltriethoxysilane (KH590) and hydroxyl groups on the surface of silica (SiO2) particles. Subsequently, HTPB-coated SiO2 superhydrophobic particles were obtained through the thiol-ene click chemistry reaction between the SiO2 nanospheres and the hydroxyl terminated polybutadiene (HTPB). Depending on the polar attraction between the terminal hydroxyl groups of HTPB and the hydroxyl groups on the surface of SiO2, SiO2 nanospheres could be firmly coated with HTPB. Fortunately, stable and durable superhydrophobic lipophilic SiO2 particles (Si-HTs) was obtained. Because of the existence of micro-nano structures, the resultant Si-HTs could easily float on the oil-water surface, and effectively absorb oil solvents more than 4 times its own weight with an ultrahigh separation efficiency above 99%. Even under strong acid and strong alkali conditions or in the seawater environments, the Si-HTs were afforded with effective oil-absorption capability and high recyclability over 20 times. Consequently, the Si-HTs prepared show great potential as a superhydrophobic nanoparticle for low-cost, high-efficiency and environmentally friendly oil-water separation.