Removal of oil using styrene-modified apple pomace

The utilization of waste biomass is a significant issue for sustainable development. Oil contamination has been recognized as one of the major threats to the aquatic ecosystem. Aiming to the remediation of the oil spill accidents, an apple-pomace-based and styrene-modified oil absorbent, denoted as SMAP, was synthesized by graft copolymerization via active hydroxyl group on cellulose anhydroglucose unit (AGU) of apple pomace using styrene as the monomer, ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as homogeneous reaction medium, benzoyl peroxide (BPO) as initiator, and N, N-dimethylformamide (DMF) as cosolvent at 80 ℃ with the reaction time 3 h. The FTIR and CP/MAS ¹³C NMR spectra of SMAP and AP (apple pomace) showed that styrene was successfully grafted onto AP, the surface wettability by contact angle measurement revealed the hydrophobicity of SMAP was greatly enhanced, and thermogravimetric analysis showed the thermal stability of SMAP was improved. SMAP showed superior oil absorbency, floatability, and reusability to AP. The maximum sorption capacities of SMAP for model oils of toluene and chloroform were 10.5 g·g⁻¹ and 15.6 g·g⁻¹, respectively, which were higher than those of AP (3.1 g·g⁻¹ and 7.5 g·g⁻¹). The sorption kinetics showed that the sorption of toluene and chloroform by AP and SMAP followed the pseudo-second-order kinetics. The ionic liquid AmimCl could be recovered by chromatography column and vacuum distillation and showed better reusability. This work provides a facile way for fabricating cellulosic materials that might be used for the remediation of oil spill accidents.