RSM optimized soy protein fibre as a sorbent material for treatment of water contaminated with petroleum products

Abstract

The aim of this study is to investigate the use of modified soy protein fibre (SPF) as a sorbent material for treatment of water contaminated with petroleum products. Studies were done with diesel, petrol, kerosene and petroleum ether both in pure oil medium and oil–water medium. Oleophilic behaviour of SPF was enhanced by successive benzoylation (Bz-SPF) and graft copolymerization. Response surface methodology was applied to find maximum optimum graft percentage as per IV optimal design comprising of 31 experimental runs. Process variables investigated were monomer concentration, reaction temperature, reaction time, potassium persulphate (KPS): Ferrous ammonium sulphate (FAS) molar ratio and pH. Percentage graft yield was monitored as response and characterized through FTIR and SEM techniques. There is antagonist two-factor interaction between monomer × KPS:FAS ratio with significant negative main effect of KPS:FAS molar ratio on graft yield. Chemical modification of SPF, enhanced water resistance and acid–base resistance properties. Bz-SPF and Bz-GSPF showed high sorption capacities for diesel (30.7–43.55 g/g), petrol (23.6–37.72 g/g), kerosene (15.5–34.06 g/g) and petroleum ether (9.7–28.88 g/g) both in pure oil medium and oil–water medium. Thus, eco-friendly SPF shows high performance as sorbent material for removal of oil.