Magnetic superhydrophobic polyurethane sponge modified with bioinspired stearic acid@Fe3O4@PDA nanocomposites for oil/water separation

Abstract

Nowadays it is imminent to treat oily wastewater as the frequent occurrence of oil spills and discharge of oily wastewater requires rapid remediation of the damaged environment. Inspired by mussels, this study provides a simple and cost-effective method for preparing magnetic polyurethane sponges with superhydrophobicity and superlipophilicity by combination of self-polymerization of dopamine, covalent deposition of magnetic Fe 3 O 4 nanoparticles, and modification of hydrophobic stearic acid. The prepared sponges have been comprehensively evaluated for its superhydrophobic stability in acid-base corrosion solution, high temperature, different salt solutions and organic solvents as well as the separation efficiency and application potential. Results show that the prepared sponge exhibits good chemical stability and a high selectivity in absorption of oil or organic substances in the aqueous solution with a water content in oil less than 0.2%. Besides, with superior absorption capacity and reusability, the prepared sponge can absorb 42 times as much oil as its own weight and be reused 50 times without any obvious decrease of performances. Thus, the prepared sponge has promising potential in the field of oil-water separation. • Magnetic superhydrophobic polyurethane sponge was fabricated by coating stearic acid@Fe3O4@polydopamine nanocomposites. • The as-prepared superwetting sponge exhibited a high selectivity in absorption of oil or organic substances. • The as-prepared superwetting sponge demonstrated high separation efficiency of oil/water mixture. • The as-prepared superwetting sponge delivered excellent chemical, thermal and mechanical stability.