The research objective in this study is to find solutions for immobilization of Zn(II) ions from spent printing developer in the printing industry by adsorption on natural, low-cost adsorbents: activated carbon (AC, Norit Row 0.8 Supra), natural zeolite (NZ, clinoptilolite) and their mixtures (AC+NZ); by doing this, environmentally-harmful metal Zn(II) would be eliminated. Because of the complexity of printing wastewater we studied the adsorption onto various adsorbents, to gain an insight into

more »

... the influence of heavy metal Zn(II) on the sorption behavior of these adsorbents, the effect of their nature and optimal concentration, and determine the adsorption capacity and the appropriate contact time. Therefore, these adsorbents of the defined pore size and structure were applied to examine their adsorption efficiency in the removal of Zn (II) ions from the spent printing developer sample. Concentrations of Zn(II) ions in fresh and spent printing developers before and after the adsorption were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), using a PerkinElmer Elan 5000 mass spectrometer. The adsorption of Zn(II) ions onto activated carbon, clinoptilolite and there mixture was studied in laboratory batch mode. The adsorption equilibrium data for Zn(II) ions on AC, NZ and (AC+NZ) were analyzed in terms of the Freundlich isotherm model. The results provided strong support for the Zn(II) ions adsorption onto these adsorbents, and all the data fitted well to the Freundlich isotherm (R 2 ≥0.988). The lowest correlation coefficient for Zn(II) ions was obtained using the mixtures of activated carbon and clinoptilolite. The adsorption capacities of Zn(II) ions decreased in the order: AC>NZ>AC+NZ.