Oil removal from water surface using reusable and absorptive foams via simple fabrication of liquid natural rubber (LNR)

Abstract

A novel macroporous and oleophilic Natural Rubber (NR) foam is prepared through a vulcanization process using methanol (CH3OH) as solvent at different compositions of crosslinking agent (Disulphur Dichloride, S2Cl2). NR was firstly modified to reduce its molecular weight by photochemical oxidation method to produce Liquid Natural Rubber (LNR). This spongy-like foam made of LNR was firstly reported here, has produced interconnected open-cell structures with pore volume ranged from 1.83 mL/g to 4.28 mL/g and diameter sizes between 2.09 μm and 13.24 μm. The absorption capability of LNR-foam resembled to the cotton fiber-based sorbent where it absorbed most of oil products by up to 9.39 g/g. The porous materials reached the saturation limit within 5 min of low-viscosity oils, and 15 min for higher-viscosity oils. In a simulated oil slick system, this LNR macroporous and hydrophobic foams maintained its high oil absorption capacity in the ranged of 3.54 g/g to 9.39 g/g. About 90% of absorbed oil is being recovered and the LNR-foams are able to perform up to 20 absorption cycles which demonstrated a good reusability. Hence, this new type of natural-based modified absorbent has the potentials to be commercialized.