Microbial Electrochemical Technology Drives Metal Recovery

Abstract

Raw metals are fundamental to the global economy as they are essential to maintain the quality of our life as well as industrial performance. A number of metal-bearing aqueous matrices are appealing as alternative supplies to conventional mining, like solid industrial and urban waste leachates, wastewaters and even some natural extreme environments (e.g., deep marine sediments, geothermal brines, etc.). Some of these sources are already managed for recovery, while others are not suitable either because they are too low in content of recoverable metals, they contain too many impurities that would interfere with classical recovery processes or they are cost-prohibitive. Microbial electrochemical technologies, that results from the interactions between microorganisms, metals and electrodes, in which the electron transfer chain associated with microbial respiration plays a key role and can contribute to overcoming these challenges. This chapter summarizes the general routes through which microbes can dissolve metals from ores and support metal recovery, leading to nano-scale and macro-scale functional products. The relevant sources of metals are highlighted as well as the challenges and opportunities to turn the microbial electrochemical process into a sustainable leaching and recovery technology in the near future are also mentioned.