Highly efficient oil-water separation and oil adsorption with hydrophobic hydrotalcite/polyurethane porous composite foam

Oil/organic solvent leakage will pose a serious threat to the environment and ecology, and efficient oil-water separation has attracted much attention in recent years. A new porous composite form hydrophobic hydrotalcite/polyurethane (PU-L) was successfully prepared using hydrophobic nano-hydrotalcite and polyurethane (PU) via a thermally induced phase-separation method. The PU-L was modified with methyltrichlorosilane (MTS) to obtain the modified composite form (PU-L-M), which can be employed for oil/water separation. The morphology, chemical composition and oil-water separation properties of PU-L-M were systematically examined using XRD, SEM, XPS, TG-DTA and contact-angle measurements. The PU-L-M exhibited an impressive adsorption capacity for organic solvents (silicone oil, cyclohexane, toluene, chloroform and corn oil), ranging from 8.66 to 36.71 g/g. Results confirmed the ability of PU-L-M to effectively separate organic materials from wastewater. Additionally, PU-L-M exhibited excellent reusability after 10 cycles of oil adsorption. The recovery rate of corn oil by PU-L-M was as high as 87.03 %. The adsorption of corn oil by PU-L-M conformed to the pseudo-second-order kinetic model. Notably, the chemical interaction among PU, MgAl-L-M, and MTS was occurred. A novel type of PU-L-M composite foam was successfully designed and prepared, and it exhibited excellent performance for oil-water separation and oil adsorption.