Gold Biosorption From an Electronic Scrap Leachate Using Dead Biomass of Aspergillus Niger

The demand for gold is constantly growing due to its various technological, medical, jewelry, and other applications. One example is its use in electronic circuits that eventually become waste, causing accumulation and recycling problems that also lead to a lack of recovery of the metal from so-called electronic scrap. In addition to the above, gold deposits face more technological challenges for their exploitation, and low grades are common in current deposits. One consequence of the low concentration of gold-bearing minerals is reflected in the volume of leaching chemicals used to dissolve the gold or gold-bearing species, which, in the short term, contaminate the soil and groundwater. Due to the ability of some biomasses to adsorb and recover metals in solution, biomining is proposed as a technological innovation to, for example, recover gold from a solution. Biomining, or the recovery of precious metals with microorganisms, is a technique based on the use of non-pathogenic bacteria, yeasts, and fungi. In this research, the bioadsorption of gold from an electronic scrap leachate was studied using dead biomass of the fungus Aspergillus niger , for a system under a discontinuous regime. Experimental results show that through bioadsorption after 120 minutes of biomass-leachate contact, it is possible to recover up to 50% of the gold in solution, depending on the pH, as well as the amount of biomass in contact with the solution and the availability of active or functional sites in the biomass.