@article{
author = "Rajić, Nevenka and Stojaković, Đorđe and Jevtić, Sanja and Zabukovec-Logar, Nataša and Kovač, Janez and Kaučič, Venčeslav",
year = "2009",
abstract = "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.",
publisher = "Elsevier, Amsterdam",
journal = "Journal of Hazardous Materials",
title = "Removal of aqueous manganese using the natural zeolitic tuff from the Vranjska Banja deposit in Serbia",
pages = "1457-1450",
number = "2-3",
volume = "172",
doi = "10.1016/j.jhazmat.2009.08.011"
}