Preparation of superhydrophobic cellulose aerogel sponge from waste paper and its application in oil-water separation

The separation of oil and water mixtures has become crucial globally due to the frequent incidents of petroleum substances and organic solvents leaking into water and the growing necessity to treat industrial wastes containing oil. Most methods for removing oily pollutants are often time-consuming, costly, and low-efficiency, and they also cause secondary pollution. The absorption method of oily pollutants has been noticed due to its high efficiency, low energy requirement, and simple application. Aerogels are considered one of the most attractive absorbents for separating oil and water mixtures due to their unique characteristics, such as low density, high porosity, and suitable oil absorption capacity. In this research, a superhydrophobic cellulose aerogel was prepared using crystalline cellulose extracted from waste paper, TiO₂, SiO₂ nanoparticles, and vinyltrimethoxysilane by a simple dip-coating method for the first time. It was then utilized to remove oily pollutants and organic solvents from water. XRD, FESEM, EDS, FT-IR, DLS, BET, and water contact angle measurements were employed to identify and characterize the synthesized materials and the modified aerogel. The prepared cellulose aerogel exhibited a water contact angle of 163.39˚ and a sorption capacity ranging from 28.5 to 31.5 g.g^− 1 for various oily pollutants and organic solvents. Additionally, this superhydrophobic aerogel demonstrated excellent reusability and effectively removed emulsified oil droplets in water. This research showed that the aerogel made from waste paper can effectively separate oily pollutants and organic solvents from water.