Adsorption of methylene blue on strongly basic anion exchange resin (Zerolit DMF): kinetic, isotherm, and thermodynamic studies

Abstract

This work explored the adsorption potential of Zerolit DM-F (ZDMF) resin for methylene blue (MB) removal form aqueous system in batch mode. Both linear and non-linear models have been applied to kinetic and isotherm data. Practical feasibility of ZDMF was testified by performing breakthrough, desorption, and regeneration studies. Results showed optimum adsorption (24.75 mg/g) at pH 10. Contact time studies showed equilibration time ranged between 30 and 90 min for various MB concentrations (Co—25–200 mg/L). Kinetic modeling studies showed applicability of pseudo-first-order model at various MB concentrations while, isotherm studies showed applicability of Freundlich model at various temperatures. Thermodynamics studies showed endothermic and spontaneous process. The breakthrough studies showed that 550 mL of MB solution (Co—50 mg/L) which was prepared separately in deionized water and tap water matrix could be passed through the columns without detecting MB traces. The breakthrough and exhaustive capacities in deionized water and tap water matrix were found to be 27.5 and 45 mg/g, respectively. Desorption studies showed optimum MB recovery (86%) with 5M HCl solution while, regeneration studies revealed 10.20 and 16.28% loss in adsorption and desorption after five consecutive cycles, respectively.