Bio-electrochemical reactors using AMI-7001S and CMI-7000S membranes as separators for silver recovery and power generation

Bioelectrochemical reactors using AMI-7001S and CMI-7000S membranes were investigated for silver recovery and power generation. High silver removal (83.73-92.50%) and columbic efficiency (11.50-19.89%) were obtained in CMI-based reactor after 24 h, although, some diffusion of Ag+ ions was observed. In contrast, substrate loss was found in AMI-based reactor, which caused low overall performance. At an initial Ag+ concentration 2000 mg/L, a maximum power density of 5396 mW/m3 and 3385 mW/m3 were obtained in CMI and AMI-based reactor, respectively. Under SEM analysis, different morphologies of metallic silver deposits were detected on the cathode surfaces, and was confirmed by EDX and XRD technique. High diversity of anodic microbial communities were also found, in which Firmulates, Proteobacteria, and Bateroidetes were dominant phyla. Geobacter sp. and other exoelectrogens could be detected while no Shewanella-like sequences were retrieved. The study suggests that CMI-7000S showed better performance when compared to AMI-7001S at the same operational conditions.