Zeolite bearing tuff as an adsorbent for heavy metals removal from aqueous solutions and a acid mine drainage

Zeolite bearing tuff (stilbite 27%) from Vetunica deposit, localized in northern marginal parts of the Kratovo-Zletovo volcanic area in Republic of Macedonia was investigated as an adsorbent for removal of copper, zinc, manganese and lead ions from synthetic aqueous solutions and acid mine drainage from Sasa lead - zinc mine in Republic of Macedonia. In order to determine the metals uptake at equilibrium a series of experiments were performed under batch conditions from single ion solutions. Experiments were carried out at different initial concentration of metal ions, at initial pH = 3.5, temperature of 20±1oC and agitation time up to 360 min. The adsorption isotherm of the metal ions on the adsorbent was determined and correlated with the Langmuir and the Freundlich adsorption isotherm models. The Langmuir isotherm exhibited a better fit for the adsorption data for copper, lead and manganese ions, but adsorption of zinc ions is fitting by the Freundlich isotherm. According to the maximum adsorption capacity (qe) it was determined the selectivity of zeolite bearing tuff for the respective heavy metal ions. The selectivity series was Pb2+ > Cu2+ > Zn2+ >Mn2+. The adsorption of copper, zinc, manganese and lead ions from diluted solution and acid mine drainage on to zeolite bearing tuff occurs efficiently