Kinetics, isotherm and thermodynamic studies of Reactive Black 5 removal by acid acrylic resins

The removal of Reactive Black 5 from aqueous solutions onto the strongly basic acrylic anion exchangers of type 1, namely Amberlite IRA-458 and Amberlite IRA-958 were investigated. According to the results, the equilibrium time was found to be 180 min for each Reactive Black 5-anion exchanger system. Adsorption experiments indicated that the amount of the dye adsorbed on both Amberlite IRA-458 and Amberlite IRA-958 was dependent on the initial dye concentration in the range of 50–500 mg/L. Modeling of kinetic results showed that the sorption process of the dye adsorption on both anion exchangers was best described by the pseudo second-order kinetic model in the entire investigated concentration domain. The effect of temperature on dye removal showed that the maximum capacity was obtained at 318 and 308 K for the dye adsorption on Amberlite IRA-458 and Amberlite IRA-958, respectively. The adsorption isotherm data were fitted well to the Langmuir isotherm and according to this model, Amberlite IRA-458 and Amberlite IRA-958 exhibited the highest monolayer sorption capacity of 1295.93 and 1723.964 mg/g. Various thermodynamic parameters, such as ΔG, ΔH and ΔS were evaluated and revealed that Reactive Black 5 adsorption process on both Amberlite IRA-458 and Amberlite IRA-958 was endothermic and favourable.