Biosorption of zinc and cadmium by pre-treated inactive bacteria

An alternative for reducing heavy metals in different ecosystems is the use of microorganisms in bioremediation processes, one of the main environmental problems of the present century. The aim of this work is to determine the effectiveness of bacterial, pretreated, and inactivated biomasses in biosorption of zinc (Zn (II)) and cadmium (Cd (II)) in monometallic and bimetallic solutions. Dry heat was applied to inactivate biomasses of Bacillus cereus (AL-30), Acinetobacter sp. (AL-134) and Micrococcus sp. (AL-138); subsequently they were treated with KOH and HCl. In all cases, a significant increase in obtaining values of both ions, higher than 40 mg.g-1, was found. These results allowed forming different mixed bacterial systems which were efficient in biosorption, from monometallic solution, with percentages over 91,4 % and 87,6 %, for Zn (II) and Cd (II), respectively. In the bimetallic solution, a higher capture of cadmium regarding zinc was observed by mixed bacterial systems. The potentialities of the inactivated bacterial biomass and with chemical pretreatment to be used in effluent purification processes with the presence of these metals were evidenced.