Solubilization of toxic metal mineral by the Aspergillus niger strain and oxalic acid

Abstract

The objective of this study is solubilization of lead and arsenic from toxic metal mineral lead arsenate hydroxide - hydroxymimetite with oxalic acid and distilled water. Furthermore, the Aspergillus niger (A. niger) strain was applied for solubilization of lead and arsenic from hydroxy-mimetite. Oxalic acid was confirmed as the best leaching agent and was able to mobilize 96% of As and 1.49% of Pb. Also, the oxalic acid was capable of solubilizing inorganic Pb from crystalline compound and transforming it into the different organic Pb phase, which partially precipitated as lead oxalate Pb(C2O4). Our experimental studies bring insight into the biogeochemical cycles of the studied elements and have potential application in the bio-hydro-metallurgical processes for recovery of arsenic and lead from different materials (e. g. toxic metal minerals, mining ores, contaminated soil and sediment and other environmental area).