Evaluation of the biosorption potential of Aspergillus flavus biomass for removal of chromium (VI) from an aqueous solution

Chromium biosorption potential of live and dead biomass of Aspergillus flavus was analyzed by batch experiments under various experimental conditions like pH, adsorbent dose, exposure period, and temperature. Maximum biosorption of hexavalent chromium was observed at pH 3.5 with adsorbent dose 2.5 g at 30°C. Three days were considered as the optimum exposure period for chromium removal for live biomass, whereas 1.3 hours exposure period for dead biomass of A. flavus. The equilibrium data were examined by Langmuir and Freundlich isotherms. Freundlich isotherm appeared to be the best fit model. Phytotoxicity test was conducted to check the effect of the treated chromium solution on the seed germination, seedling length, and vigor index of Vigna radiata. Only 23% germination was reported in chromium metal-treated V. radiata seeds, but germination and growth parameters of mung bean seeds were significantly increased in the chromium solution after treatment with dead and live biomass. The chromium biosorption potential showed the following trend: dead A. flavus > live A. flavus. Hence, live and dead biomass of A. flavus can be applied as a safe and economically feasible biosorbent for hexavalent chromium elimination for the treatment of industrial effluent or wastewater system.