Abstract:
To find an optimum condition and efficiency of dregs in the adsorption of chromium and copper from synthetic wastewater and wastewater from electroplating factories. The experiment was carried out in a laboratory scale-completely mixed batch system at room temperature. The heavy metals concentration in the wastewater was measured by Atomic adsorption spectrophotometer before and after adsorption by dregs. Two sample of synthetic wastewater was prepared; one with either chromium or copper and one with both chromium and copper at concentration of 200 and 20 mg/L, respectively. For adsorption kinetic studies samples were taken for heavy metals measurement at 0.5-24 hours of adsorption time. The pH range from 2-9 was studied to determine the optimum value. Isotherm was identified by varying the amount of dregs from 0-1.2 g/100 ml. Furthermore, leaching test of heavy metals was performed by waste extraction test (WET). The optimum condition for this study was 24 hours of contact time and pH range of 7-9. The adsorption isotherm of chromium can be described by both the Freundlich and Langmuir isotherm. For copper, the equilibrium was not followed the adsorption isotherm because the removal of copper is based on precipitation. Therefore, it would be plausible to use dregs in the preliminary treatment of wastewater to remove some of the heavy metals, and to reduce the amount of chemicals used in pH adjustment step in the precipitation process.