Removal of aqueous manganese using the natural zeolitic tuff from the Vranjska Banja deposit in Serbia

• Published in: Journal of hazardous materials Vol. 172; no. 2; pp. 1450 - 1457
• Main Authors: Rajic, Nevenka, Stojakovic, Djordje, Jevtic, Sanja, Zabukovec Logar, Natasa, Kovac, Janez, Kaucic, Venceslav
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 30.12.2009; Elsevier
• Subjects: Adsorption; Applied sciences; Chemical engineering; Clinoptilolite; Exact sciences and technology; Ion Exchange; Kinetics; Langmuir–Freundlich isotherm; Manganese - isolation & purification; Manganese removal; Pollution; Serbia; Thermodynamics; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; Zeolite; Zeolites - chemistry; Serbia; Europe; Clinoptilolite; Langmuir–Freundlich isotherm; Kinetics; Zeolite; Manganese removal; Second order; Tuff; Adsorption isotherm; X ray analysis; Modeling; Sorption; Batchwise; Counter ion; Thermodynamic properties; Diffusion; Ion exchange; Sorbent; Langmuir-Freundlich isotherm; Activation energy
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2009.08.011

The natural zeolite tuff from the Vranjska Banja deposit (Serbia) has been studied as sorbent for Mn(II) ions from aqueous solutions. The zeolite sample containing mainly clinoptilolite (more than 70%) removes Mn(II) ions by ion-exchange process, which was confirmed by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDXS). XPS showed that there is no surface accumulation of Mn but an almost uniform distribution inside the sorbent; EDXS confirmed that Mn(II) replaced the clinoptilolite Na counter ions. The sorption isotherms were studied at 298 K by batch experiments showing that the Mn(II) removal is best described by the Langmuir–Freundlich or Sips model. The kinetics followed the pseudo-second-order model, the activation energy being 128 kJ mol −1. The intra-particle diffusion is not the rate-controlling step in the sorption of Mn(II) on clinoptilolite. Thermodynamic data suggest spontaneity of the endothermic ion-exchange process in the 298–338 K range.