Eu(III) removal from aqueous solutions using raw and modified pomegranate peel as biosorbents

Removal of Eu(III) from aqueous solutions was studied using pomegranate peel in raw and modified form as potential biosorbent. Low-cost chemical modifications of the material using acidic and alkaline reagents under moderate conditions were applied to improve its sorption ability. The sorption study was performed in the metal concentration range C init :5–300 mg L −1 , regarding the effect of sorbent dosage, competitive ions, temperature and contact time. It was revealed that the biosorbent modified by alkaline reagent, exhibited considerable sorption capacity with q max value 83.3 mg g −1 for europium. Langmuir and Freundlich linear isotherm equations were satisfactorily applied as well as simulation of the kinetics data at various temperatures using pseudo-first- and pseudo-second-order equations and thermodynamic data in order to explore the sorption mechanism. Meanwhile, characterization of the biosorbents before and after sorption was performed by SEM–EDS, XRD and FTIR while chemical modification of the biosorbents surface functional groups, revealed the involvement of carboxyl, hydroxyl and phosphate groups in biosorption. Desorption experiments demonstrated the environmental compatibility of the tested materials which could be used as potential sorbents in environmental technology.