Heavy metal removal from industrial wastewater by clinoptilolite

Abstract

Clinoptilolite- a natural zeolite has been investigated for the removal of heavy metals from the wastewaters. A pyrex-glass column of 30 mm diameter and 600 mm height was used. The column was filled with the conditioned clinoptilolite of 0.5-1 mm. In the first stage of the research, synthetic wastewater containing single cation 0.02 N and 0.04 N Cu and 0.02 N Fe and Zn solutions were passed through the column. Two liter of 0.02 N Cu and 750 ml of the 0.04 N Cu solution was treated with 100 percent removal efficiency. Clinoptilolite column was regenerated for the reuse when the removal efficiency decreased. The cation exchange capacities were calculated as 1.0663 and 1.5342 meq/g clinoptilolite for 0.02 N and 0.04 N Cu solutions, respectively. In the second stage of this research, the same procedure was repeated with the actual wastewater samples of the equalization and the neutralization tanks of the Telka-Rabak Electrolytic Copper Industry. A volume of 1811 ml of the wastewater of the equalization tank and 180 ml of the neutralization tank wastewater, which had high concentrations of Ni, Zn, Cu and Fe, was treated with 100 percent efficiency. The cation exchange capacities of clinoptilolite for the wastewater of the equalization and the neutralization tanks for Cu were 0.4483 and 0.4274, respectively. It was observed that only one third of the single copper ion solutions were obtained with the actual wastewater having competing ions such as Zn, Fe and Ni. The experimental results also indicate that the clinoptilolite is an effective cation exchanger for the removal of the metals from the wastewater and the removal efficiency is higher when there is not ant competing ions.