Application of a novel lignocellulosic biomaterial for the removal of Direct Yellow 50 dye from aqueous solution: Batch and column study

This study focused on the utilization of sugarcane bagasse for the removal of Direct Yellow 50 dye from aqueous solution. Sugarcane bagasse was used in native, modified and immobilized forms. Polyethyleneimine (PEI) was used as the modifying agent and modified biomass depicted the enhanced biosorption capacity as compare to native and immobilized forms. Batch mode experiments were conducted to explore the biosorption potential of sugarcane bagasse at different operating conditions. The best conditions for the maximum dye removal were found to be lower pH (2.0), low biosorbent dose (0.05 g) and low temperature (30 °C). Maximum dye removal with native, PEI treated and immobilized biomass was 43.17, 65.8 and 15.7 mg/g, respectively. Kinetic studies were carried out and results showed the best fitness of pseudo-second-order kinetic model on the experimental results. Experimental results were also interpreted by different equilibrium isotherms. Thermodynamic study was carried out to evaluate Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). Continuous mode experiments were conducted to check the optimized conditions of bed height, flow rate and initial dye concentration for maximum dye removal. Maximum dye removal in continuous study was 10.4 mg/g at 4 cm bed height and 50 mg/L initial dye concentration. Thomas and bed depth service time (BDST) models were applied on the experimental results of column study. The results prove that sugarcane bagasse can be used as a potential biosorbent for the removal of Direct Yellow 50 dye from aqueous solutions.