Enhanced Adsorptive Removal of a Model Acid Dye Bromothymol Blue from Aqueous Solution Using Magnetic Chitosan-Bamboo Sawdust Composite: Batch and Column Studies

The removal of an acid dye bromothymol blue (BTB) from aqueous solution using Fe2O3/chitosan-bamboo sawdust (FeCBSD) composite was studied. Isotherm modeling indicated that the data best followed Langmuir isotherm, with adsorption capacity (qm) of 217.39 mg/g at a contact time of 30 min and an adsorbent dose of 0.5 g/L. In column studies, the data fitted well into the Thomas model with an adsorption capacity of 225.13 mg/g at a flow rate of 20 mL/min and a bed height of 5 cm. The breakthrough capacity, breakthrough time and exhaustion time decreased with the increasing flow rate. The adsorption process followed pseudo-second order kinetics, which was controlled by both liquid-film and intra-particle diffusion mechanisms. The negative values of ?Go (7.2410.94 kJ/mol), positive values of ?Ho (41.27109.13 kJ/mol) and ?So (0.150.38 J/mol/K) indicated spontaneity, endothermic nature and an increased randomness at solid-solution interface, respectively. The results indicated that the FeCBSD effectively removed BTB from wastewater, which may be magnetically recovered. 2015 American Institute of Chemical Engineers Environ Prog, 34: 14441454, 2015