Synthesis of Superhydrophobic/Superoleophilic stearic acid and Polymer-modified magnetic polyurethane for Oil-Water Separation: Effect of polymeric nature

The superhydrophobic/superoleophilic materials based on polyurethane foams have been layered with three different polymers and extensive modification with iron/magnetic nanocomposite. The general desires are to study the effect of the polymer layer and to eliminate the oil contaminant from the oil-water system which is crucial due to the development of environmental technologies. These materials were generated by facile dip-coating two-step method on the polyurethane foams (PUF) surface. PUF was directly layered with polydopamine/polypyrrole/polyaniline (PDA/PPy/PANI) and incorporated with Fe-SA (stearic acid) nanocomposites by ultrasonication and refluxing. In addition, characterization by FTIR, SEM/EDX, XRD, and TGA presented that the polymer layer and Fe-SA nanocomposites successfully covered the PUF surface caused by the chelating interaction between the carboxylates and active sites on iron particles due to intermolecular hydrogen bond interaction. Interestingly, the water contact angle (WCA) measurement of the nanocomposites displayed that the contact angle significantly improved up to 164°. After 20 cycles of oil absorption capacity, the WCA steadily remained up to 153° indicating powerful superhydrophobic properties of the materials. Furthermore, the oil absorption capacity of the materials was evaluated using typical oil-water separation methods such as reusability, separation efficiency, and oil permeate flux. The results exhibited that the modified PUFs have enhanced the absorption capacity up to 44 times the foam weight, 99 % separation efficiency, and about 8000 L.m-2.h-1 oil flux. For oil removal, the dyed oil phase was rapidly absorbed within 2 s confirming the highly used products for a wide area of oil-water separation. PDA-coated PUF nanocomposites obtained the most outstanding results due to their remarkable interfacial adhesion properties which provide larger active functional groups for hydrogen bonding interaction on PUF surface and Fe-SA nanocomposites.