Facile Fabrication of Superhydrophobic/Superoleophilic Cotton for Highly Efficient Oil/Water Separation

Abstract

This paper presents a facile and versatile strategy to fabricate robust and superhydrophobic/superoleophilic cotton for the removal of oils and organic solvents from polluted water. The superwettability cotton was prepared via in-situ hydrolysis of tetraethoxysilane (TEOS) on the cotton fiber surface using polyvinylpyrrolidone (PVP) as a coupling agent and subsequent hexadecyltrimethoxysilane modification. By simply adjusting the molecular weight of PVP and the concentration of NH3•H2O, the surface roughness of SiO2-modified cotton fibers could be well controlled to generate cotton fibers with excellent superhydrophobicity. The prepared cotton fibers were used as superabsorbents for oil/water separation. It absorbed up to 35 times and 50 times its own weight of n-hexane and chloroform, respectively, while repelling water completely. After collecting the absorbed oils via a simple squeezing method, the cotton could be reused for at least 5 cycles. Moreover, the whole procedure was carried out in a mild environment, with no intricate instruments or toxic reagents.