*5.2. Dual-Chambered MEC*

Dual-chambered MECs are often used in typical configurations and consist of an anodic and a cathodic chamber separated by the use of a membrane, as shown in Figure 6. The H-type MEC is a widely utilized dual-chambered MEC. Dual-chambered MECs are difficult to scale up because of their complex assemblies and large volumes with high internal resistance. The utilization of a membrane serves a dual purpose. It lowers the crossover from the anode to the cathode chamber and helps to prevent short-circuits at the cathode chamber, as well as aiding in the preservation of the purity of the product collected on the cathode side. The proton exchange membrane (PEM) is the most often used membrane since it is intended to only allow free protons to flow through while employing –SO3 functional groups [68,69]. Alternative membranes, including anion-exchange membranes (AEM), such as AMI7001, bipolar membranes, and charge-mosaic membranes (CMM) [70] have also been investigated in MECs, in addition to the conventional membranes [71]. Cheng and Logan created a reactor in which an anion-exchange membrane (AEM) was used between the electrodes to achieve their desired results. The anode chamber was filled with graphite granules that were heated with ammonia gas, which increased the current densities, resulting in a reduction in the amount of time required for reactor accommodation. A carbon cloth served as the cathode, and a platinum catalyst was maintained near the membrane, which was connected to the outside circuit via a titanium wire [72].

**Figure 6.** Schematic representation of a dual-chambered microbial electrolysis cell.

Various patents associated with MEC reactor architecture (Figure 7) are displayed in Table 1.

**Figure 7.** *Cont*.

**Figure 7.** (**A**) Top and front view of graphite brush anode used in the microbial electrolysis cell; (**B**) microbial electrolysis cell.


