Kinetics and mechanism of dye biosorption onto an untreated antibiotic waste

This study focuses on the possible use of Waste P. mutilus to remove Basic Blue 41, cationic dye from aqueous solutions. Batch kinetic studies were carried out as a function of pH, particle size, biomass amount and dye concentration to determine the decolorization efficiency of biosorbent. The highest dye removal yield was achieved at pH 8–9. Equilibrium occurred within about 60 min. The pseudo-second order kinetic model adequately describes the kinetic data. The Langmuir, Freundlich and Tempkin models were used to describe the isotherm data; of which the Freundlich model described the isotherm data with high correlation coefficient (r2 = 0,994). The maximum monolayer biosorption capacity of biosorbent material was found as 111 mg/g. Also, it was observed that the intra-particle diffusion was not the only rate-controlling step. The adsorption mechanism may be partly a result of the ion exchange or complexation between the dye ions and function groups on dead biomass surface. Finally the proposed biosorbent was successfully used for the decolorization of BB41 in synthetic wastewater conditions.