Superhydrophobic modification of the surface of cellulosic materials based on honeycomb-like zinc oxide structures and their application in oil–water separation

Abstract

Honeycomb-like zinc oxide structures were prepared on the surface of cellulosic materials including cotton fabric fiber and filter paper fiber through plasma treatment followed by wet chemical reaction, the effect of plasma treatment is to increase the wettability and reactivity of cellulosic materials, so that the zinc oxide can nucleate and grow into a honeycomb-like structure on the cellulose fibers. The superhydrophobic surface was then obtained by modifying stearic acid on the zinc oxide structure. The microstructure, chemical composition and state, and wettability of the cellulosic materials were studied in detail. After the modification, the water contact angle and water sliding angle of the modified cotton fabric were 151° and 3.4°, respectively, and those of the modified filter paper is 154° and 4.5°, which indicates super-hydrophobicity. Due to the structural characteristics of zinc oxide-stearic acid structure, the superhydrophobic structure can maintain superhydrophobic performance in strong acidic or strong alkaline environments or after ultrasonic vibration treatment. Further, superhydrophobic modified cotton fabric and filter paper can be used for oil–water separation and adsorption of oil droplets in aqueous solution, and the oil–water separation efficiency is greater than 90%. This method of superhydrophobic modification of cellulosic materials has broad application prospects.