Biosorption of Basic Violet 5BN and Basic Green by waste brewery’s yeast from single and multicomponent systems

Abstract

The biosorption of Basic Violet 5BN (BV) and Basic Green (BG) by waste brewery's yeast (WBY) from single and binary systems was investigated. For the single system, the adsorption of both dyes is pH-dependent and the optimum value is 5.0. At a lower initial concentration, the kinetic data agree well with both pseudo-first-order and pseudo-second-order models, while at a higher initial concentration the data fit better with the pseudo-second-order model. External diffusion is the rate-controlling step at initial fast adsorption, and then the intraparticle diffusion dominated the mass transfer process. Equilibrium data for BV and BG fit better with the Langmuir model. The maximum biosorption capacities of WBY onto BV and BG obtained at 303 K are 114.65 and 141.89 mg/g, respectively. Thermodynamic analysis reveals that the adsorption process for the two dyes is spontaneous and exothermic. The hydroxyl, amino, amide, carboxyl, and phosphate groups are responsible for the biosorption based on Fourier transform infrared analysis. The presence of BV significantly affects the biosorption of BG, but not vice versa. The P-factor model and Sheindrof-Rebhun-Sheintuch equation gave a good description of the equilibrium adsorption data at the multicomponent system.