Electrochemical control and minimization of hydrogen sulfide formation in anaerobic systems
Formation of hydrogen sulfide represents a major challenge in the operation of wastewater collection systems. Hydrogen sulfide is malodourous and toxic gas, which causes corrosion of pipes, wells, and constructions, hence damaging the structural integrity of the collection systems and significantly...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/675727 |
| Acceso en línea: | http://hdl.handle.net/10803/675727 |
| Access Level: | acceso abierto |
| Palabra clave: | Electrocatalysis Electrocatàlisi Electrocatálisis Sulfide oxidation Oxidació de sulfurs Oxidación de sulfuros Manganese oxide Òxid de manganès Óxido de manganeso Hydrogen sulfide formation Formació de sulfur d'hidrogen Formación de sulfuro de hidrogen Wastewater treatment Depuració d'aigües residuals Depuración de aguas residuales 504 628 |
| Sumario: | Formation of hydrogen sulfide represents a major challenge in the operation of wastewater collection systems. Hydrogen sulfide is malodourous and toxic gas, which causes corrosion of pipes, wells, and constructions, hence damaging the structural integrity of the collection systems and significantly reducing their lifetime. Control of hydrogen sulfide formation, accumulation and emission is normally handled by the dosing of chemicals to the waste stream, which leads to considerable operating costs and risks associated with the transport, storage and handling of chemicals. Electrochemical treatment is an attractive alternative to the existing technologies for sulfide control, as it offers a robust removal of sulfide in situ and avoids the costs and risks related to chemical usage. Mechanisms and products of electrochemical sulfide oxidation are strongly dependent on the nature of the electrode materials employed. For example, oxidation of sulfide at mixed metal oxide (MMO) coated titanium electrodes mainly proceeds via its indirect oxidation by the electrochemically generated oxygen, resulting in sulfur, sulfate and thiosulfate as final products [1]. However, indirect oxidation is non-selective, and about ∼50% of the total electrons is used for organics oxidation, thus lowering the current efficiency of the process. Sulfide is an electrochemically active species and can also be directly oxidized to elemental sulfur at low anodic potential, hence reducing the energy requirements of the treatment. Though sulfur is biologically available, its utilization of as electron acceptor in bacterial metabolism is limited mainly due to low solubility of sulfur in water. Thus, electrochemical oxidation of sulfide to sulfur should help to minimize the reformation of sulfide. However, questions remain regarding the suitability of electrochemical abatement of hydrogen sulfide for real-scale applications due to several drawbacks such as the lack of appropriate anode materials and gradual electrode passivation with the electrodeposited sulfur. Therefore, the main goal of this thesis was to investigate the performance of electrochemical sulfide oxidation to elemental sulfur by: i) using carbon-based electrode materials known to have high selectivity towards S0, ii) developing new anode materials capable of fast and selective sulfide oxidation to elemental sulfur at low applied potentials, and iii) applying different regeneration strategies for the removal of the electrodeposited S0 and sulfur recovery. |
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