Equilibrium and kinetic studies of methylene blue biosorption by sugar palm dregs

Abstract

The biosorption of methylene blue onto sugar palm dregs was studied in batch biosorption system to know the equilibrium and kinetics. The operating variables studied were initial of solution pH and biosorbent dose. The Langmuir and Freundlich isotherm models were used for modelling the biosorption equilibrium. The experimental was found that the increase solution pH increased the adsorption capacity from 1.72 mg g-1 at pH 2 to 15.71 mg g-1 at pH 8. The dye removal was from 54% to 93% for an increase in the biosorbent dose from 0.5 gL-1 to 2 gL-1 while adsorption capacity was reduced from 21.75 to 9.3 mg g-1. The equilibrium studied that was well interpreted by the Langmuir model with monolayer sorption capacity (qm) is 23.866 mg g-1. In kinetic studies the fits of pseudo-first order, pseudo-second order, Ritchie and intraparticle diffusion kinetic models were investigated. It was obtained that the biosorption process followed the pseudo-second order rate kinetics.