Investigation of heavy metal removal from salty wastewater and voltage production using Shewanella oneidensisMR‐1 nanowires in a dual‐chamber microbial fuel cell

Abstract

Heavy metal removal and simultaneous energy production were studied using a dual chambered Microbial Fuel Cell inoculated with Shewanella oneidensis MR‐1 in the anode. Synthetic wastewater was prepared with Cu (II), Mg (II), Mn (II), Zn (II), Na, and Phenol based on desalter effluent from refinery processes at different metal concentrations. In this study, a maximum open‐circuit voltage of 517.6 mV was reached at Conc. 5 with wastewater in the anode chamber, and 127.7 mV at Conc. 3 was produced with synthetic wastewater in the cathode chamber. Moreover, μ at Conc. 5 was 0.1133 h−1, demonstrating bacterial growth under metal and phenol concentrations. The highest metal removal in the anode for Cu (II), Mg (II), Mn (II), Zn (II), and Na was 93%, 85%, 93%, 88%, and 36%, respectively. In the cathode chamber the removal of Cu (II), Mg (II), Mn (II), Zn (II), and Na was 98%, 49%, 57%, 59%, and 36%, respectively. During the operation in the anode, SEM images showed that the bacterial nanowires are formed in response to toxic and anaerobic environments which contribute to the bacterial growth. These nanowires increased the metal removal and the voltage production as a consequence of a higher electron rate from the anode to the cathode due to the higher extracellular membrane surface area. S. oneidensis is a bacterium with metal‐reducing characteristics, and it is suitable for metal removal and electron transport from carbon sources, demonstrated in voltage production with microbial fuel cells.

The Potential Use of Pseudomonas stutzeri as a Biocatalyst for the Removal of Heavy Metals and the Generation of Bioelectricity

“…(2024) studied an MFC with synthetic wastewater, managing to reduce Cu (II), Mg (II), Mn (II), Zn (II), and Na by 93 85, 93, 88, and 36%, respectively, and mentioned that bacterial nanowires are also formed in toxic environments and are responsible for the elimination of toxic ions present in the substrate and, at the same time, allow a higher rate of electron transport, generating greater efficiency in the MFC [68]. Other metal ions (lead, cadmium, chromium, and copper) have also been reduced using MFCs, highlighting the importance of the physiological activity of biofilms and extracellular polymeric substances for the reduction of these metals, where the use of nanoparticles and anodic and cathodic biosynthesis are the most notable points [69,70]. Treatments for the improvement of electrodes in terms of porosity and electron conduction have been intensely investigated in published documents, as well as metal nanoparticles and the isolation of microorganisms for their use as biocatalysts with the aim of re-potentiating the generation of electrical energy, which are being considered with greater importance by researchers [71,72].…”