Removal of heavy metals by Escherichia coli (E. coli) biofilm placed on zeolite from aqueous solutions (case study: the wastewater of Kerman Bahonar Copper Complex)

Industrial wastewater needs to be treated because of the heavy metals presence and their effects on the environment. The aim of this study was to remove heavy metals ions such as copper and zinc from aqueous solutions by using Escherichia coli (E. coli) biofilm which was placed on zeolite. The paper was experimental. Synthetic and real samples were evaluated in laboratory scale. To evaluate the removal efficiency, the effective parameters such as pH, copper and zinc concentrations, and contact time were examined. Optimal conditions were obtained with experiments on the synthetic samples. To study the adsorption isotherms, Langmuir and Freundlich isotherm models were investigated. The copper and zinc cations maximum removal efficiency at 40 mg/L within 10 days was obtained as 54.61% and 57.35%, respectively. By using Langmuir isotherm, the experimental data were fitted with correlation coefficients of 0.98 and 0.95 for copper(II) and zinc(II), respectively. The results showed that the hybrid of zeolite and bacterial biofilm system has the best efficiency for removing the metal copper and zinc cations.