Removal of Reactive Dye from Wastewater by Adsorption Using ECH Cross-Linked Chitosan Beads as Medium

Abstract

The feasibility of the removal of reactive dye from wastewater using a novel adsorbent, ECH cross-linked chitosan beads, as medium was examined. The effect of the pH and the initial concentration of the dye (RR222) solution on the adsorption capacity of the ECH cross-linked chitosan beads were also investigated. It was found that the initial dye concentration and the pH of the solution significantly affected the adsorption capacity. An increase in initial dye concentration results in the increase of adsorption capacity while an acidic pH was found to be favorable for the adsorption of dye. It was also found that the equilibrium adsorption of RR222 could be adequately described by using the Langmuir model (r 2 ≥ 0.999). Moreover, results showed that the adsorption rate of RR222 onto ECH cross-linked chitosan beads could be described by using the second-order kinetic model, suggesting that chemical sorption instead of mass transfer was the rate-limiting step for the adsorption process. The maximum monolayer adsorption capacity obtained from the Langmuir model was extremely high as compared to the data reported in literature; 2252 g/kg at 30°C with a pH of 3.0. Therefore, ECH cross-linked chitosan beads could be a feasible medium for the removal of reactive dye from wastewater and potentially an alternative for the decolorization of wastewater.