Comparative Analysis of Hexavalent Chromium Biosorption Efficiency Using Dead and Live Aspergillus nomius Biomass

Abstract

Daily industrial activities especially in developing countries produce and discharge wastes containing heavy metals into the water resources making them polluted, threatening human health and the ecosystem. One such heavy metal is Chromium, the hexavalent form of which is extremely toxic and carcinogenic. Biosorption, the process of passive cation binding by dead or living biomass, represents a potentially cost-effective way of eliminating toxic heavy metals from industrial wastewater. The potential of microorganisms to remove metal ions in solution has been extensively studied; in particular, live and dead fungi have been recognized as a promising class of low-cost adsorbents for the removal of heavy metal ions. Fungal biomass has various advantages; hence, it needs to be explored further to take its maximum advantage in wastewater treatment. In this study, we discuss the live and dead fungi characteristics of sorption, factors influencing heavy metal removal. Biosorption studies were performed with both dead and live biomass and the effectiveness of Cr (VI) biosorption was compared for each parameter. It was observed that biosorption was maximum (approximately): 82% while using sulfuric acid as the pre-treatment agent (hence only dead biomass) and also maximum of 96.5% at 1 N. The optimum pH for maximum biosorption was 6 when dead biomass was used, while it was 2 when live biomass was used. Maximum Chromium removal of 86% was obtained using 2 g live biomass whereas 0.5 g of dead biomass was enough to obtain the maximum efficiency.96% chromium was removed at 25° C using dead biomass, whereas, maximum removal of about 84% was obtained when live biomass was used for biosorption and it took place at 35° C. Maximum Cr (VI) removal of about 95% was obtained when dead biomass was used and 69% when live biomass was used, both at 1mg/L metal concentration. 0.5 g of dead biomass in 100 ml, 1 mg/L solution, was optimum for Cr (VI) removal, while for live biomass, maximum Cr (VI) biosorption of 63% was obtained when 1.5 g of it was used in 300 ml solution. It was finally concluded that dead fungal biomass has better biosorption potentials and also some other inherent advantages over live biomass.