Enhanced superhydrophobicity and durability of modified cotton cloth for efficient oil-water separation

The development of simple, low-cost, and efficient oil/water separation membranes is still a major challenge in the field of wastewater treatment. In this study, an oil/water separation membrane is prepared based on low-cost cotton cloth (CF) through a simple solution soaking treatment without using organic solvents . Pristine CF is treated first with concentrated alkali and then chemically grafted by sodium methyl silicate (SMS) onto the surface to obtain oil/water separation membrane (SMS-O-CF). This process not only increases the roughness of the CF but also endows the surface with superhydrophobicity due to the outward extension of methyl groups, resulting in a water contact angle (WCA) of 155° and good self-cleaning ability. The SMS-O-CF achieves efficient separation for various oil/water mixtures and maintains a separation efficiency up to 96 % and a flux of over 11,557 L·m −2 ·h −1 after 220 cycles under neutral conditions. Moreover, the modified CF also exhibits excellent acid/alkaline resistance and wear resistance. Regardless of the 12 h acid/base immersion, 100 min water wash, or 200-cycle mechanical abrasion, SMS-O-CF still exhibits high flux and separation efficiency. Raw material cost for preparing SMS-O-CF is as low as 1.0 dollar/m 2 . The preparation of SMS-O-CF has provided a green manufacturing method for developing low-cost and efficient oil–water separation membranes.