Optimization the Removal of Nickel from Simulated Wastewater by A Pseudomonas aeruginosa Biofilm Supported on Clinoptilolite

Background & Objectives: Nickel toxicity and its bioaccumulation potential in organisms at high concentrations, the use of cost-effective and environmental friendly remediation methods is necessary for the removal of nickel from polluted water and wastewaters. Bacterial biofilm be able to remove heavy metals from aqueous solutions and accumulate them in their cell structure. Therefore, the purpose of this study was to evaluate the nickel removal efficiency by biofilms of Pseudomonas aeruginosa supported on clinoptilolite. Methods: In this study, a strain of Pseudomonas aeruginosa as a biofilm coating supported on clinoptilolite. To ensure the establishment of biofilms, scanning electron microscopy was used. The effect of concentration, pH, support medium dosage, temperature and contact time were evaluated in 5 levels, and finally, the results were assessed by adsorption isotherm models. Results: The findings indicated that the maximum removal efficiency by biofilms of Pseudomonas aeruginosa supported on clinoptilolite (99/47%) was achieved in optimal condition containing 900 mg. L-1of nickel concentration, pH of 9, supporting medium dosage (clinoptilolite) 2.36 g. L-1, temperature of 25 ° C and the contact time of 45 days. The fitness of data in Freundlich adsorption isotherm model revealed that the heterogeneity of adsorbent surface. Conclusion: This study indicates that the use of biofilm coating on the surface of clinoptilolite, can be a good candidate to remove the nickel from the aqueous media