• journal_title：Clay Minerals
• Contributor：S. Tomić ; N. Rajić ; J. Hrenović ; D. Povrenović
• Publisher：Mineralogical Society of Great Britain and Ireland
• Date：2012-
• Format：text/html
• Language：en
• Identifier：10.1180/claymin.2012.047.1.81
• journal_abbrev：Clay Minerals
• issn：0009-8558
• volume：47
• issue：1
• firstpage：81
• section：Articles

Natural zeolitic tuff from Brus (Serbia) consisting mostly of clinoptilolite (about 90%) has been investigated for the reduction of the Mg concentration in spring water. The sorption capacity of the zeolite is relatively low (about 2.5 mg Mg g^–1 for the initial concentration of 100 mg Mg dm^–3). The zeolitic tuff removes Mg from water solutions by ion exchange, which has been demonstrated by energy dispersive X-ray analysis (EDS). The extent of ion exchange was influenced by the pH and the initial Mg concentration. Kinetic studies revealed that Lagergen’s pseudo-second order model was followed. Intra-particle diffusion of Mg²⁺ influenced the ion exchange, but it is not the rate-limiting step. Rather than having to dispose of the Mg-loaded (waste) zeolite, a possible application was tested. Addition to a wastewater with a low concentration of Mg showed that it could successfully make up for the lack of Mg micronutrient and, accordingly, enabled the growth of phosphate-accumulating bacteria A. Junii, increasing the amount of phosphate removed from the wastewater.