Kinetic and Equilibrium of Biosorption of Methylene Blue by Anaerobic Granular Sludge in Wastewater

With anaerobic granular sludge as adsorbent, the adsorption kinetics and thermodynamics of methylene blue (MB) from aqueous solution was studied by batch adsorption technique.The pseudo-first order, pseudo- second order models and Langmuir, Freundlich isotherms models were used to describe the kinetic data.The experimental results show that the anaerobic granular sludge had strong and fast speed adsorption capacity for MB adsorption in wastewater. The adsorption equilibrium could be reached in 2h, and the maximum adsorption rate was 98.6%. the pseudo-second order equation is the best model that describes the adsorption behavior.The equilibrium data were fitted to Langmuir isotherms and the equilibrium adsorption was well described by the Langmuir isotherm model. The calculation values of thermodynamic parameters present that the adsorption is spontaneous and endothermic in nature.Our results suggest the anaerobic granular sludge is a potential MB cleaner in wastewater.