Bioelectrocatalytic Reduction of Tellurium Oxyanions toward Their Cathodic Recovery: Concentration Dependence and Anodic Electrogenic Activity

Abstract

Regulation on the usage of trace toxic metals and their depletion necessitates their detoxification/recovery. Tellurium scarcity in the environmental matrix and its multitude applications depicts its worth for recovery from toxic ionic forms. Bioelectrochemical systems (BESs) facilitate metal detoxification/recovery. In this study, a novel double-chambered BES coupled with a biotic anode and abiotic cathode was operated using varied concentrations of toxic tellurite oxyanions (Te 4+ ) as a terminal cathodic electron acceptor (CEA), facilitating bioelectroreduction of Te 4+ to elemental tellurium (Te 0 ) (cathode) and wastewater treatment (anode). Results depicted a Te 0 element recovery of 45.3% with a tellurite removal of 54.7% in the abiotic cathode with a simultaneous substrate degradation of 67% in the biotic anode. The cathodic Te 0 recovery with increased CEA-dependent electrotrophy has proportionally influenced the anodic microbial enzymatic activity. Bioelectrochemical characterization showed an increased anodic electrogenic performance relative to the increased CEA concentrations, achieving a comparatively higher power density of 0.044 W/m 2 in the Te-C condition. Recovered Te 0 samples were analytically characterized for structural/compositional functionalities and speciation variations to confirm the presence of Te 0 element and its crystalline nature at the cathode. The study provided the application feasibility of BESs in favoring Te detoxification/recovery at the abiotic cathode, while regulating the anodic microbial electron/enzymatic/metabolic flux.

Syngas Fermentation to Acetate and Ethanol with Adaptative Electroactive Carboxydotrophs in Single Chambered Microbial Electrochemical System

“…Electrode kinetics and biocompatibility of the electrodes were evaluated through the Tafel plots (drawn from the LSV) based on the Butler–Volmer equation [ 22 , 25 , 26 , 27 , 28 , 29 ] ( Figure 6 ). Log integration of the generated reduction current in LSV depicts the kinetics of the charge transfer, which accounts for the substrate (Syngas) utilization and product formation [ 22 ].…”

Advances in Biological Wastewater Treatment Processes: Focus on Low-Carbon Energy and Resource Recovery in Biorefinery Context

“…These integrated processes evaluate industrial wastewater treatment at multiple levels of assessment, with the influence of symbiotic reactions increasing the process efficiency. These processes involve microbial electrocatalysis, and the BET/EO process potentiality lies in its ability to degrade a spectrum of pollutants/contaminants/toxins in applications including wastewater treatment (BET/EO), salt removal (desalination), and metal removal/recovery (electrodeposition/biomineralization), taking advantage of the symbiotic reactions that take place in the hybridized biological and electrochemical system [ 19 , 58 , 59 , 60 ] ( Figure 3 ). Anodic biofilm attachment and microbial community entities in relation to the synergy with the electrode play a crucial role in complex (pollutants/contaminants/toxins/metals) treatment by metabolically biocatalyzed electrochemical oxidation [ 61 ].…”

“…electrodes) provide biological systems with a potential gradient (in situ/applied), which could be an alternative to genetic manipulations for higher product/energy formation [ 21 , 73 ]. These non-genetic approaches induce increased electrogenic activity in microbes and effectively contribute to microbe–microbe/microbe–electrode interactions, increasing process efficiency [ 58 ]. In situ/applied energy during the bioelectrochemical process increases the electron transfer through the conduction band in a conductive material, which is used as a source of reducing equivalents by the electroactive bacteria to derive specific biobased products from solid/liquid/gaseous organic substrates.…”

“…electrodes) provide biological systems with a potential gradient (in situ/applied), which could be an alternative to genetic manipulations for higher product/energy formation [21,73]. These non-genetic approaches induce increased electrogenic activity in microbes and effectively contribute to microbemicrobe/microbe-electrode interactions, increasing process efficiency [58]. In situ/applied…”