Bio-sorptive remediation of crude oil polluted sea water using plantain (Musa parasidiaca) leaves as bio-based sorbent: Parametric optimization by Taguchi technique, equilibrium isotherm and kinetic modelling studies

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This study investigated the potential of employing plantain leaves as a natural bio-based sorbent for crude oil spill polluted seawater remediation. Type L 9 (3 4 ) Taguchi orthogonal array technique was used to evaluate the effect of four independent bio-sorption factors at three different levels (crude oil initial concentration (X 1 7.8, 11.5 and 15.6 g/L), seawater-crude oil temperature (X 2 25, 35 and 45 °C), bio-sorbent dosage (X 3 1, 2 and 3 g) and bio-sorbent particle size (X 4 1.18, 2.36 and 4.72 mm) on two response indices (bio-sorption efficiency (%) and bio-sorption capacity (g/g)). Taguchi optimization technique, numerical-desirability index function optimization technique and a proposed optimization method were utilized to determine the optimum bio-sorption factors needed for the optimum bio-sorption efficiency and bio-sorption capacity. The results demonstrated that the crude oil bio-sorption efficiency of the plantain leaves was significantly influenced by X 1 , X 3 and X 4 and the bio-sorption capacity was mainly influenced by X 1 and X 3 . The optimum bio-sorption efficiency and the optimum bio-sorption capacity were 99.05 % and 12.82 g/g, respectively, obtained at optimum combination of factors and levels of X 11 (7.8 g/L), X 33 (3 g) and X 41 (1.18 mm) for bio-sorption efficiency and X 13 (15.6 g/L) X 31 (1 g) for bio-sorption capacity. The Freundlich and Dubinin-Rudeshkevich isotherm models best explain the equilibrium bio-sorption data, while the pseudo-second order kinetic model best describes the bio-sorption kinetics. The bio-sorptive remediation mechanism followed dual mechanism of physical and chemical bio-sorption and the mass transfer controlled by film diffusion. The maximum bio-sorption capacity ( K f ) was 14.0 gg -1 .