Removal of Zinc from Industrial Wastewaters Using Microscopic Green Algae Chlorella Vulgaris

Environment contamination by heavy metals is a major issue threatening human health. One of the biological processes for removing toxic metals from wastewater is biosorption. The aim of this study is to determine the rate of zinc (Zn) biosorption in industrial sewages by Chlorella vulgaris.
This laboratory scale experimental study was performed during April 2014 to October 2014 in Environmental Health Engineering Research Center, Kerman University of Medical Sciences. For determining zinc biosorption by Chlorella was measured under different conditions (pollutant concentrations, adsorbent dosage, contact time and pH). The rate of residual zinc was determined using atomic absorption instrument. Experiments were also performed in real conditions on electroplating industry sewage sample. Adsorption isotherms and metal ions kinetic modeling onto the adsorbent were determined based on Langmuir, Freundlich and first and second order kinetic models.
Findings: At constant temperature of 25ºC, optimal pH 7, contact time of 60 minutes and adsorbent concentration of 2g/L, zinc adsorption efficiency was reported to be 67.72% for real sample and 90.23% for synthetic sample. Based on the obtained results, zinc adsorption followed Langmuir model and second order kinetic equation.
Discussion & As a result of high adsorption potential in real sample, 67.720/0, Chlorella vulgaris can be efficiently used for zinc removal from industrial wastewaters.