University of Tehran/Springer International Journal of Environmental Research 1735-6865 8 4 2014 10 01 Comparative Studies on the Bioremediation of Hexavalent and Trivalent Chromium using Citrobacter freundii: Part I-Effect of parameters controlling Biosorption 1227 1134 829 10.22059/ijer.2014.829 EN P. Divyasree Department of Materials Engineering and Indo-French Cell for Water Sciences, Indian Institute of Science, Bangalore, 560012, Karnataka, India J.J. Braun Department of Materials Engineering and Indo-French Cell for Water Sciences, Indian Institute of Science, Bangalore, 560012, Karnataka, India S. Subramanian Department of Materials Engineering and Indo-French Cell for Water Sciences, Indian Institute of Science, Bangalore, 560012, Karnataka, India Journal Article 2014 10 15 The potential of Citrobacter freundii, a Gram negative bacteria for the remediation of hexavalent<br />chromium (Cr(VI)) and trivalent chromium (Cr(III)) from aqueous solutions was investigated. Bioremediation<br />of Cr(VI) involved both biosorption and bioreduction processes, as compared to only biosorption process<br />observed with respect to Cr(III) bioremediation. In the case of Cr(VI) bioremediation studies, about 59 %<br />biosorption was achieved at an equilibrium time of 2 h, initial Cr(VI) concentration of 4 mg/L, pH 1 and a<br />biomass loading of 5x1011 cells/mL. The remainder, 41 %, was found to be in the form of Cr(III) ions owing to<br />bioreduction of Cr(VI) by the bacteria resulting in the absence of Cr(VI) ions in the residue, there by meeting<br />the USEPA specifications. Similar studies were carried out using Cr(III) solution for an equilibrium time of 2<br />h, Cr(III) concentration of 4 mg/L, pH 3 and a biomass loading of 6.3x1011 cells/mL, wherein a maximum<br />biosorption of about 30 % was achieved. https://ijer.ut.ac.ir/article_829_1c077e7c812e8769ddd716d440a3728f.pdf