Evaluation of calotropis procera fruits as a bioadsorbent for removing of acid red 73 dye from the aqueous solutions

Abstract

acid red 73 dye is a colorant dyes is using in many dyeing processes and may causes many harmful effects to aquatic life with lasting effects. So, it must be removed from aquatic environment, one of the most useful methods is the using of plants biomass in its removal. Therefore, both of raw andacid activated (with HCl) Calotropis procera fruits (CPF) was used for the adsorption of Acid red 73 (AR73) dye from an aqueous solution.Various parameters (including dye concentration, contact time, dose, temperature, and pH) were optimized to obtain the maximum adsorption capacity.Surface morphology and surface functional groups of both raw and modified CPF samples were investigated by scanning electron microscope (SEM) and fourier transformation infrared (FTIR). Among the adsorbents, HCl-CPF had more adsorption capacity (65%) than CPF (22.4%) at an initial concentration of 20 mg/L and at 30°C.The thermodynamic parameters, such as the changes in enthalpy (ΔH°), entropy (ΔS°), and Gibbs free energy (ΔG°), showed that the adsorption is exothermic, random and nonspontaneous at high temperatures.