Zirconium diboride assisted superhydrophobic/superoleophilic surface modification of polyurethane sponge for continuous oil-water separation and emulsion purification

Abstract

BackgroundWith rapid industrialization, water pollution by accidental oil spills and industrial wastes dumping into water bodies has become a severe threat to the marine ecosystem. In this regard, usage of superhydrophobic/superoleophilic sorbent is forecasted perhaps one of the best solution to recover oil and natural solvents from contaminated water owing to its high absorption capacity, and recyclability. MethodsHerein, we report zirconium diboride modified polyurethane sponge (ZrB2@PUS) prepared by facile dip coating technique at ambient condition for selective oil/water removal. The ZrB2@PUS was further functionalized using octadecyl trichlorosilane (OTS) in presence of toluene to impart superhydrophobicity. Significant findingsMicrostructural analysis revealed that ZrB2 platelets anchored onto smooth struts of PUS thereby increasing surface roughness, whereas, OTS helps in decreasing the surface tension and enhancing the non-wettability. The ZrB2@PUS exhibited a contact angle ∼166° and ∼0° for a sessile water and oil droplet, respectively. Moreover, ZrB2@PUS was found suitable for removal of various oil and organic solvents from oil-water mixture with absorption capacity reaching ∼83–129 g/g and capacity retention ∼92–97% after 20 cycles in static and dynamic conditions. OTS-functionalized ZrB2@PUS also successfully explored for separating SDS stabilized diesel-in-water and toluene-in-water emulsion, demonstrating feasibility for wastewater treatment containing oil and organic solvents.