Batch studies of hexavalent Chromium (VI) adsorption from wastewater by using Lelliottia amnigena

Abstract

Industrial and human activities and agriculture can contaminate the water sources and make serious problems for the health of living beings. A significant contaminant is heavy metals. They directly and indirectly penetrate into the drinking water and wastewater that make it necessary to be removed. Chromium as a heavy metal plays an important role in polluting water sources due to its extensive use and extreme toxicity of it. In this study a chromium resistant bacterium that was isolated from Babol-Rood River, Babolsar, Mazandaran, Iran, applied to absorb chromium from aquatic solution. The bacterium was identified as Lelliottia amnigena based on its morphology and 16S rRNA sequence assay. This study checked the chromium biosorption from aqueous solution in diverse situation such as isotherm condition, different pH, different temperature, kinetic situation. It also computed primary and secondary metal concentration, initial and terminal biomass concentration, absorption differences between living and dead bacterial biomass, effect of shaker on absorption, influences of bacterial (life phase) on absorption, and the effect of desorption compounds in addition of using different methods of dyeing. Not only was this bacterium resistant to chromium but also it can remove cadmium and lead; thus, it can be used in binary or ternary biosorption treatments. Optimum situation was determined based on all the factors that were mentioned above. To show surface adsorption of bacteria, SEM-EDX and FTIR analysis were done before and after the metal adsorption. The results showed that Lelliottia amnigena successfully and effectively could remove heavy metals from aqueous solution.