title: Removal of barium and strontium from aqueous solution using zeolite 4A.
abstract: The adsorption efficiency of Sr(2+) and Ba(2+) from aqueous solutions by zeolite 4A was investigated. Adsorption studies were carried out both in single and binary component systems. The single ion equilibrium adsorption data were fitted to three isotherm models: Langmuir, Freundlich and Dubinin-Radushkevich. The Langmuir model represents the equilibrium data better than the Freundlich model in the studied initial metal concentration (0.3-25 mmol L(-1)) in both the single and binary component systems. The obtained RL (separation factor or Langmuir parameter) values were in the range of 0-1 indicating that Sr(2+) and Ba(2+) sorption were favorable. The obtained mean free energy value for adsorption of Ba(2+) and Sr(2+) was 8.45 kJ mol(-1) and 9.12 kJ mol(-1), respectively, indicating that both ions were uptaken through an ion exchange process. The maximum adsorption capacities (Qmax) were 2.25 mmol g(-1) and 2.34 mmol g(-1) for Ba(2+) and Sr(2+) ions, respectively. Also, the study of the competitive sorption of ions in the binary system showed that zeolite 4A preferentially adsorbs cations in the following order: Ba(2+) < Sr(2+).
authors.affiliation: Materials, Environment and Energy Laboratory (UR14ES26), Science Faculty of Gafsa, University of Gafsa, Gafsa 2112, Tunisia.
authors.forename: Manel
authors.initials: M
authors.lastname: Araissi
authors.affiliation: Materials, Environment and Energy Laboratory (UR14ES26), Science Faculty of Gafsa, University of Gafsa, Gafsa 2112, Tunisia.
authors.forename: Imen
authors.initials: I
authors.lastname: Ayed
authors.affiliation: Materials, Environment and Energy Laboratory (UR14ES26), Science Faculty of Gafsa, University of Gafsa, Gafsa 2112, Tunisia; Science Faculty of Gafsa, University of Gafsa, Gafsa 2112, Tunisia E-mail: y.moussaoui2@gmx.fr.
authors.forename: Elimame
authors.initials: E
authors.lastname: Elaloui
authors.affiliation: Science Faculty of Gafsa, University of Gafsa, Gafsa 2112, Tunisia E-mail: y.moussaoui2@gmx.fr; Physical Organic Chemistry Laboratory (UR11ES74), Science Faculty of Sfax, University of Sfax, Sfax 3018, Tunisia.
authors.forename: Younes
authors.initials: Y
authors.lastname: Moussaoui
mesh_terms: D000327:Adsorption; D001464:Barium / Q000737:chemistry*; D007474:Ion Exchange; D007477:Ions; D013324:Strontium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D017641:Zeolites / Q000737:chemistry*
chemical_list: D007477:Ions; D014874:Water Pollutants, Chemical; D017641:Zeolites; D001464:Barium; D013324:Strontium