Zinc sorption on montmorillonite

Abstract

Montmorillonite is a clay mineral from the group of phyllosilicates with laminated structure and permanent negative charge on the layers surface, which fact can be used for sorption of cations or ion exchange reactions. In this project, the exchange of zinc ions for sodium ions in interlayers is examined. For batch experiments the sodium form of montmorillonite was used. Different zinc salts were used: nitrate, sulphate and acetate. The results show that adsorption process can be described with Langmuir-Freundlich or Langmuir adsorption isotherm. Maxima of adsorbed amounts were 1,08 ± 0,07 meq∙g-1 ; 1,25 ± 0,32 meq∙g-1 and 0,86 ± 0,03 meq∙g-1 in case of nitrate; sulphate and acetate respectively. The pH value of solutions increased during the adsorption except from acetate, where a small decrease can be observed.