BIOTECHNOLOGICAL RECYCLING AND RECOVERY OF METALS FROM SECONDARY RAW MATERIALS THROUGH BIOGENIC SYNTHESIS OF NANOPARTICLES

Abstract

ABSTRACT. The waste electrical and electronic equipment (WEEE) is an important secondary source for renewable extraction of valuable metals and raw materials. The mineral biotechnologies are promising alternative to the current industrial chemical technologies for waste treatment, which are often accompanied with negative environmental impact. Here we report a systematic biotechnological strategy for recycling, recovering and extraction of metals from WEEE as biogenic formed nanoparticles. The process is based on two general steps – bioleaching (through autotrophic/heterotrophic bacteria), and extraction from the effluent as biosynthesised nanoscale materials. The obtained analytical data revealed that copper was bioleached in the form of nanoparticles, the efficiency being more than 90 %, which was the highest achieved value in comparison with the other metals. The recovered content of gold was less than 50 %, but the efforts for improvement of microbial leaching efficiency of Au are still in progress. The reported eco–friendly biotechnological approach enables proper implementation of new resource recovery–oriented recycling strategies with reduced risk of negative impact on nature.

Keywords

• biotechnological recycling
• secondary raw materials