Magnetically superhydrophobic kapok fiber for selective sorption and continuous separation of oil from water

Abstract

Magnetically superhydrophobic oil sorbent was prepared by directly immobilization of Fe3O4 nanoparticles on the surface of kapok fiber and subsequent hydrophobic modification. The results show that the as-prepared fibers demonstrated excellent superhydrophobicity and magnetic responsivity. They also exhibited high separation efficiency for oil/water mixtures and can quickly absorb floating oils on water surface via magnetic driving. Compared with raw fiber, the oil sorption capacity of as-prepared fiber for n-hexane, toluene, chloroform, paraffin oil, gasoline, and diesel can increase by 70.8%, 58.5%, 96.1%, 23%, 37.3%, and 30.5%, respectively. Furthermore, the fibers can be used to continuously separate a large quantity of oil contaminants from water surface by means of a vacuum pump. Importantly, the water contact angel still can reach above 143° after being repeatedly used several times and immersed in various oils and harsh water environments for long time period, implying excellent recyclability and chemical durability in the oil sorption. The findings suggest that the magnetically superhydrophobic kapok fiber has the prospect of potential applications in the removal and recovery of spilled oil contaminants.