Elaboration of Hydrophobic/Oleophilic “Natural 3D Luffa Sponge” for Selective Oil/Water Separation

Nowadays, oily wastewater is mainly discharged from petrochemical, textile, metallurgical and food industries, and other oil contaminated water. This discharge is causing ecological and environmental problems. Therefore, there is a growing demand for developing more effective and environmentally friendly techniques and materials for oil/water separation. Conspicuously, the approach of using porous, green, eco-friendly, and low-cost sorbent materials from the biodegradable biomass is one of the wise ways. Herein, a facile and green strategy was developed to prepare hydrophobic and oleophilic sorbent material based on a Luffa sponge (LS). The luffa sponge is the dried fruit of “Luffa cylindrica” plant, a natural renewable fiber material that possesses a porous skeleton with a continuous three-dimensional (3D) macroporous surface structure. This lignocellulosic biomass was widely used as an absorbent for the removal of organic pollutants from water. Therefore, this biomass sponge is essentially hydrophilic material. Among many techniques that can be utilized for hydrophobic and water-repellency treatment, chlorosilane surface functionalization has been widely studied and developed. In this study, the methyltrichlorosilane (MTCS) which is one of the most common organosilane compound with formula (Si–Cl–CH) was used. After being treated with chlorosilane via solvent phase, the obtained luffa sponge displayed both hydrophobic and oleophilic behavior. Using FTIR spectroscopy and XPS, the successful chlorosilane functionalization of the luffa sponge surface has been investigated. More importantly, the prepared hydrophobic luffa sponge could absorb 4–10 times of its weight for different types of oils in only 30 s and could be recycled for many times in use. This facile approach for the elaboration of biomass-based sorbent material exhibits good and fast absorption capacity toward various types of oils and organic solvents and could be considered as a promising alternative for oil/water separation.