Microbial electrolysis: a promising approach for treatment and resource recovery from industrial wastewater

Figures & data

Figure 1. Diagrammatic representation of Double Chamber MEC.

Figure 2. Schematics of different types of Double Chamber MEC.

Figure 3. Diagrammatic Representation of Single Chamber MEC.

Table 1. Integration of Microbial Electrolysis Cell with other technologies for energy production

S. No	Integration Type	Type of Electrode	Applied Energy [Voltage/ Current)	Type	Hydrogen	Current or Power Density	Remarks	References
	1. Microbial Electrolysis Cell-Anaerobic Digestion coupled	Anode: Carbon felt Cathode: stainless-steel	0 mV	Double chamber	0.42 ± 0.05 m^3 CH4/m^3 /d	2.01 ± 0.63 A/m^2	AD-MEC loop system was used	48
	2. Microbial Electrolysis Cell-Anaerobic Digestion coupled	Anode: Carbon brush Cathode: Ti/RuO2	0.0–0.8 V	Single chamber	CH4 at 0.4 V	Steady increase in current with applied voltage	To update CH4, AD-MEC was combined.	50
	3. Microbial Electrolysis Cell with Hydrogen Bioreactor [HBR]	Anode: Graphite plate Cathode: Graphite plate	0.6 V	Single chamber	0.53 mmol/h	N/A	At 0.6 V, HBR+MEC produced the best results.	93
	4. Thermoelectric micro converter-Microbial Electrolysis Cell coupled system	Anode: Plain CF Cathode: Carbon paper with Platinum.	0.17 to 0.83 V	Double chamber	0.16 m^3 H2/m^3 /d	0.28 to 1.10 A/m^2	Thermoelectric micro-converter as power source	57
	5. Dark fermentation and Microbial Fuel Cell–Microbial Electrolysis Cell coupled system	Anode: Carbon brush Cathode: Platinum coated carbon cloth	0.33 to 0.47 V	Single chamber	0.48 m^3 H2/m^3 /d	52 A/m^3 [MEC]	Combine MFC and forest organics in a stack.	58

Figure 4. Formic acid generation using biotic and abiotic electrocatalysis.

Table 2. Value-added products obtained by employing microbial electrolysis system

S.No.	Value Added Products	Substrate	Microbial Electrolysis Cell reactor	Voltage Applied	References
1.	Hydrogen	Raw food waste	Microbial Electrolysis Cell-Anaerobic Digestion reactor Single chamber	0.8 V	(69]
2.	Methane	Raw waste Activated sludge	Microbial Electrolysis Cell-Anaerobic Digestion reactor Single chamber	0 V, 0.6 V, 0.8 V	[16]
3.	Formic Acid (HCOOH)	-	Microbial electrolysis desalination and chemical-production cell	1.2 V to 2.4 V	[77]
4.	Hydrogen peroxide (H2O2)	Organic matter	Two-chamber Microbial Electrolysis Cell	0.5 V	[34]

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