Enhanced Biosorptive Remediation of Hexavalent Chromium Using Chemotailored Biomass of a Novel Soil Isolate Bacillus aryabhattai ITBHU02: Process Variables Optimization through Artificial Neural Network Linked Genetic Algorithm

A modified biomass of a novel bacterium, Bacillus aryabhattai ITBHUO2, was investigated for the removal of hexavalent chromium [Cr(VI)] from water. It was found that modification of the biomass had an improved 28.2% higher Cr(VI) removal and 9.4 mg/g greater uptake capacity as compared to unmodified biomass. At ANN-GA optimized condition of parameters, namely, pH 2.61, biomass dose of 2.8 g/L, temperature of 44 degrees C, and initial Cr(VI) concentration of 112 mg/L, the maximum uptake capacity of biomass was achieved as 31.2 mg/g and removal was 93.6%. The residual 6.4% chromium in water was found in the form of Cr(III) instead of Cr(VI), which clearly illustrated the reduction of toxic Cr(VI) into nontoxic Cr(III) due to the detoxification capability of biomass during the sorption process. Sorption followed pseudo-second order kinetics with a monolayer pattern in an endothermic and spontaneous way. SEM-EDX and FTIR studies were used to confirm the sorption as well as the functional groups involved in the sorption process.