Removal of anionic dye eosin Y from aqueous solution using ethylenediamine modified chitosan

Abstract

In this study, chitosan was cross-linked with ethylenediamine (EDA) to prepare an outstanding sorbent for the removal of anionic dye eosin Y from aqueous solution. FTIR, DTG, XPS and zeta potential analysis were used to characterize the sorbent. The effect of particle size, solution pH, agitation rate, temperature, adsorbent dosage (50–500mg/L), contact time (10min–24h) and initial concentration of dye (50–300mg/L) on the adsorption process was investigated. Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants, and the data fitted well with Langmuir model with a maximum adsorption capacity of 294.12mg/g at 25°C. Kinetic studies followed the pseudo second-order rate model, which indicated that the chemisorption is the rate-limiting step. Thermodynamic parameters such as enthalpy change (ΔH°=−5.004kJ/mol), free energy change (ΔG°<0) and entropy change (ΔS°=−11.656J/(molK)) indicate the exothermic and spontaneous nature of adsorption.