Chitosan/coffee residue composite beads for removal of reactive dye

Abstract

The adsorption performance of chitosan beads was investigated after coffee residue blending for the removal of Reactive Red 152 as an anionic dye. The study of the dye removal of chitosan/coffee residue composite beads as a function of coffee residue concentration indicated that mass ratio of chitosan to coffee residue of 60/40 was the most useful for enhancing the dye removal. The effects of contact time, initial pH, and adsorbent dosage on the adsorption efficiency were investigated systematically. The equilibrium adsorption isotherm of chitosan/coffee residue composite beads exhibited better fit to the Langmuir isotherm model than to the Freundlich isotherm model. The maximum adsorption capacity of composite bead was 4.27 mg/g. The dye desorption of composite bead was 24.83%. SEM images confirm that after adsorption the dye were dispersed onto the composite bead surface. This study demonstrated that the chitosan/coffee residue composite can effectively remove reactive dye from aqueous solution and simply with low cost. © 2017 Elsevier Ltd. All rights reserved.