Chapter 26 - Microbial Electrochemical Heavy Metal Removal: Fundamental to the Recent Development

Abstract

Metals are extensively used by many industries such as real estate, mining, construction, and transport. These heavy metals are detrimental to the environment as most of the heavy metals are carcinogenic. Without treatment of heavy metal-containing wastewater, these may accumulate in the fishes and other aquatic flora and fauna. Upon human consumption of those fishes, it may cause carcinogenic or mutagenic conditions such as skin irritation, allergies, or dermatitis. Adsorption and other existing waste treatment technologies are unable to remove heavy metals efficiently. Conventional remediation techniques are expensive and not eco-friendly. Microbial fuel cell (MFC) is a promising technology where electroactive bacteria can be used for removal of heavy metals with simultaneous electricity generation. Heavy metals can be removed via bioelectrochemical reduction at cathode chamber using the reduction capabilities of bacteria. This chapter highlighted the principle of MFCs for heavy metal removal, microbes associated with heavy metal reduction, catabolic pathway responsible for microbial oxidation of substrate, and heavy metal reduction. The different types of heavy metals, their structure, and effects along with the advantages and disadvantages of the heavy metals removal methods of MFC compared to other existing methods. This chapter discussed different case studies for heavy metal removal from groundwater using MFCs, the factors affecting metal recovery, and challenges in MFC operation during metal reduction at the cathode. The present chapter will help the readers to understand the fundamentals of microbial electrochemical heavy metal recovery.