Sustainable lotus leaf wax nanocuticles integrated polydimethylsiloxane sorbent for instant removal of oily waste from water

Eco-friendly sorbent technology-based oil-water separation can be the most desirable approach and futuristic trend for a sustainable environment. Sorbent technology applied in oil-water separation highly desires superhydrophobic and superoleophilic materials. Lotus leaf with nanocuticular wax structures is an excellent example in nature with such a property. Polydimethylsiloxane (PDMS) is another unique material with good hydrophobic/oleophilic property and most interestingly it exhibits a safe bio-disposal in spite of being a synthetic polymer. Growth of nanocuticular natural lotus leaf wax inside a microporous PDMS sponge can be a novel, eco-friendly and sustainable solution for oil-water separation. In this study, a conventional sugar leaching technique was modified to a buoyant, lightweight and soft microporous PDMS sponge. An eco-friendly self-assembly technique was further applied to grow a framework of nanocrystalline lotus-leaf wax inside the micropores of PDMS sponge. Surface morphology, IR studies, and water contact angle (WCA) measurement were done to analyze the physico-chemical properties of the sponge. Oil absorbing capacity was tested using petrol, diesel, crude oil and other industrial pollutants like Benzene, Toluene, Xylene (BTX) etc. Entire study was supported by a theoretical isotherm study to establish the mechanism of oil sorption process. WCA of 151° ± 2° demonstrated a superhydrophobic state. Absorption capacity for floating oil varied from ~ 670 to 1400 w/w% with 99% efficiency and 65% efficiency for oil separation from stable oil-in-water emulsion. Oil retention capability was found to be excellent with no leaching of soaked oil. In addition, the sponge could be reused for 70 compression cycles. [Display omitted]