BIOSORBTION OF HEAVY METALS FROM WASTEWATER USING NONLIVING BIOMASS OF THIOBACILLUS FERROOXIDANS

摘要

Removal of heavy metals from wastewater is a major ecological problem that has been recently solved using microorganisms as means to extract heavy metal ions. In this matter, biosoiption experiments were performed using non-living biomass of Thiobacilhis jerrooxidans for the removal of Cu(II), Cd(II) and Zn(II) from synthetic wastewater. The bacterial strain was obtained locally from a metalliferous area, long time polluted with heavy metals. The maximum adsorption capacity was found to be the highest for Zn followed by Cd(II) and Cu(II). The maximum loading capacity of the biosorbent was 383.64, 346.12 and 204.75 mg/g for Zn(Ⅱ), Cd(Ⅱ) and Cu(Ⅱ), respectively. It was found that the Langmuir and Freundlich isotherm models fit the adsorption data with the biosorbent and ions. The correlation factor values (R2) for both models exceeds 0.95 in most case. This indicates that both models adequately describe the experimental data of the biosoiption of the metals. The kinetic studies show that the maximum adsorption efficiency was obtained within the first 20 minutes, at pH 5, for all metals. These results indicate that biosorbent tested has good potential for removing heavy metal ions from industrial wastewater.