Methyltrichlorosilane functionalized silica nanoparticles-treated superhydrophobic cotton for oil–water separation

Water pollution due to oil spills has become a significant concern in recent times for the marine ecosystem. The use of oleophilic/hydrophobic sorbents for oil–water separation has gained a lot of attention as an economical and environment-friendly solution. Herein, we developed a superhydrophobic/superoleophilic cotton by silica nanoparticles (~ 800 nm) treatment followed by surface functionalization with methyltrichlorosilane (MTCS). X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy studies reveal that the formation of pseudo-amorphous SiO2 NPs and a C–Si–O coverage on cotton fiber render it superhydrophobic with increased surface roughness. The MTCS/SiO2-treated cotton exhibited contact angles of ~ 173 ± 2° and 0° on the water–cotton and oil–cotton interface, respectively. Moreover, the MTCS/SiO2-treated cotton demonstrated superhydrophobicity over the entire pH range, with excellent absorption capacities for various oil–water mixtures ranging from ~ 30 to 40 times its weight.