Continuous adsorption of cationic dye (Basic Red 46): Kinetic and equilibrium studies

Abstract

A continuous fixed bed study was carried out to evaluate the adsorption of Basic Red (BR 46) on activated carbon as a function of bed height (20-100 mm), influent flow rate (30-90 mL/min), initial pH (pH 3-10) and influent concentration (50-250 mg/L). The results show that optimum adsorption occurs at pH 8 and bed height of 100 mm. Comprehensive breakthrough curve analysis was carried out to determine the effect of parameters on breakthrough time of the process. Results show that the breakthrough time increased with increasing bed height but decreased with the increase in influent concentration and flow rate. The experimental data was fitted to Langmuir and Freundlich isotherm models and was found to fit Freundlich isotherm model (R2=0.988), indicating heterogenous surface adsorption. The pseudo-first order and pseudo-second order kinetic models were applied to data collected to determine the characteristic parameters that are useful for process design of the column. The kinetic data was well fitted into the pseudo-second order kinetic model with an R2 value of 0.961. The results from the mathematical model were in good agreement with the experimental results, indicating the accuracy of the model in predicting column design.