Investigation of lanthanum removal properties of cross-linked polyvinyl alcohol-sodium alginate films by adsorption

Lanthanum, which is in the group of rare earth elements characterized as industrial vitamins, is used in the production of many technological products from lighting systems to vehicle batteries, from optical glasses to catalytic converters. However, Lanthanum-containing wastes generated by such industrial uses cause pollution that may cause environmental problems. In this respect, Lanthanum removal from industrial wastes becomes important. Lanthanum shows toxic effects for living organisms and is known to cause carcinogenic effects for humans. In this study, cross-linked PVA-NaAlj films were used as adsorbents for lanthanum removal from aqueous media. Lanthanum adsorption properties of the prepared films were investigated. For this, the effects of pH, adsorption time, initial concentration and temperature on adsorption were investigated. The optimum pH of adsorption was optimized as 4 and equilibration time as 1 hour. The adsorption was found to obey Langmuir isotherm at pH 2 and Freundlich isotherm at pH 3 and 4. The experimental maximum adsorption capacity was found to be 96,57 mg/g. It was found that the adsorption capacity increased with temperature and adsorption was endothermic. Thermodynamic parameters ∆H° and ∆S° were found to be 19,15 kJ/mol and 68,83 J/mol.K, respectively. It was observed that ∆G° values were negative at the studied temperatures and adsorption was spontaneous. The adsorbent retained its properties in five times of adsorption/desorption cycles.