NEWS
Organosulfur removal with bioelectrochemical systems
Thiols (general formula R-SH) are toxic compounds with low odor thresholds and high corrosivity. In this research, we are developing a bioelectrochemical system (BES) to reduce thiols to methane and hydrogen sulfide on a biocathode. Our aim is to provide fundamental insights into the mechanisms of thiol degradation and find favorable operating conditions at biocathodes.
DC8
Doctoral Candidate: Amin Ghaderikia
Supervisors: Annemiek ter Heijne, Albert Guisasola, Sanne de Smit, Rikke Linssen
What we’re building
We are developing a lab-scale BES reactor for thiol treatment, consisting of a two-chamber reactor with an abiotic anode and a biocathode separated by an ion-exchange membrane. Graphite-based and alternative electrode materials provide surface area for electron transfer and biofilm development, while controlled pH, and electron-donor supply, allow us to study thiol adsorption, speciation, and degradation.
How it works
1. At the anode, an abiotic oxidation reaction generates electrons and protons.
2. Electrons flow through the external circuit toward the biocathode, where a controlled potential creates a strongly reducing environment.
3. At the biocathode, microorganisms use the supplied electrons to reduce thiols, converting them mainly into methane and hydrogen sulfide, alongside possible intermediate organosulfur species.
4. The produced hydrogen sulfide can subsequently be treated in a conventional biodesulfurization process to recover elemental sulfur.
Where we are right now
We have started the first batch tests to systematically explore how pH and different electron donors affect thiol degradation. By adding selected electron donors under neutral and alkaline conditions, we aim to understand how thiols are removed in redox-driven biological treatment and which combinations lead to the fastest and most complete conversion. These results will identify the most effective pH range and electron donors, providing a targeted starting point for the subsequent bioelectrochemical reactor studies.
Figure 1. Schematic of the experimental design and laboratory batch test setup