Mg-calcite CaCO3 particle: Rapid synthesis and application in fabrication of environmentally friendly hydrophobic polyurethane sponge for oil–water separation

Abstract

The hydrophobic modification of polyurethane (PU) sponge is attracting considerable attention in the field of oil–water separation. A hydrophobic PU sponge with microsize cavities on the skeleton surface and interior was prepared with hierarchical structural Mg-calcite CaCO3 (MCC) particles as a template. Hydrophobic-modified MCC particles with controllable morphologies were firstly synthesized by a facile and rapid batch method under high-speed stirring for 1 min by the presence of cetyltrimethyl ammonium bromide. MCC particles were then blended into the starting foaming materials to fabricate hydrophobic PU/MCC sponge by in-situ polymerization method. Finally, MCC particles of PU/MCC sponge were etched by acid solution and microsize cavities were generated on the surface and interior of EPU/MCC sponge skeleton. The oil-adsorption capacity of obtained hydrophobic EPU/MCC sponge was 7.58 and 5.31 times higher than pristine PU sponge for engine oil and sunflower oil, respectively. This could be attributed to the microsize cavities on the skeleton surface and interior which would increase the skeleton flexibility and enhance adhesion level between the oil and sponge surface. The underwater CCl4 was completely adsorbed into the EPU/MCC sponge within 1 s, indicating its high adsorption speed. EPU/MCC sponge exhibited high separation selectivity and separation efficiency in gravity-driven oil-water separation. The results could provide a strategy to develop hydrophobic sponges with excellent oil-water separation property.