Development of facile superhydrophobic coating on rockwool for oil–water separation

Increased industrial oily effluent discharge endangers the environment and human health; hence, researchers are inventing practical technologies to extract oil from water. Superhydrophobic surfaces with oil-water separation capabilities have recently gained popularity. Considering this, the water-repellent and oil absorbent rockwool can be done by providing a superhydrophobic coating. In the present work, we have modified the pristine rockwool with HDTMS, TEOS, and SiO2 nanoparticles by simple immersion technique. The modified rockwool exhibits excellent water-repellent properties with a static water contact angle of more than 150° and a sliding angle of less than 10°. Additionally, it also shows excellent (100%) oil absorption properties. Oil absorption capacity and recyclability of the modified surfaces were examined by numerous sets of low/high viscous oil–water mixtures and emulsions. More importantly, oil can be reloaded after burning and squeezing of coated rockwool. Besides, the anti-dust property of modified rockwool also enhances oil recovery by keeping the surface clean from blocking particles. The performance of coated surface was investigated under several operating conditions, including elevated temperature and contact with acidic and alkaline solutions, which shows the industrial suitability after modified rockwool.