Removal of lead from battery industry wastewater by Chlorella vulgaris as green micro-algae (Case study: Kerman, Iran)

Heavy metals are among the most common pollutants found in large concentrations in wastewater of industries, causing damage to the ecosystem. The aim of this study was to investigate the level of lead adsorption by Chlorella vulgaris from industrial wastewater. To determine the degree of lead adsorption by Chlorella adsorbent, the algae was brought in to contact under various conditions (pH, contact time, lead concentration, the adsorbent's level). Then, the residual amount was measured using atomic adsorption device. The experiments were performed under real conditions on a sample of battery industry wastewater in Kerman. The adsorption isotherms and the kinetic modeling of the metal ions on the adsorbent were determined based on Langmuir and Freundlich isotherm models as well as first-order and second-order kinetics. At the constant temperature of 25 degrees C, optimal pH of 6, equilibrium contact time of 60 min, and adsorbent's level of 2 g/L, the lead removal efficiency in the real and synthetic samples was reported to be 89.26 and 93.2%, respectively. Based on the obtained results, lead adsorption followed Langmuir model and second-order kinetic equation. According to the results obtained from this study, it can be stated that Chlorella can be used effectively as an adsorbent for lead removal from industrial waste waters.