Electrooxidation of Oxacillin on a Boron-doped Diamond Electrode - A Voltammetric Investigation
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-06-23 |
| Journal | American Journal of Applied Chemistry |
| Authors | Souleymane Koné, Jean-Claude Meledje, Kouakou Jocelin Kimou, Lassiné Ouattara |
| Institutions | Université Félix Houphouët-Boigny |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research validates the use of Boron-doped Diamond (BDD) electrodes for the efficient electrochemical oxidation and quantitative analysis of Oxacillin (OXA), a persistent pharmaceutical pollutant.
- Value Proposition: BDD electrodes demonstrate high stability and effectiveness for the degradation of OXA, confirming their suitability for Advanced Oxidation Processes (AOPs) in wastewater treatment.
- Reaction Mechanism: The oxidation process is irreversible and controlled by diffusion, proceeding through both direct electron transfer at the BDD surface and indirect oxidation mediated by in-situ generated oxidative species (e.g., hydroxyl radicals).
- Kinetic Parameters: The process involves approximately two electrons (n â 2.18). Key kinetic parameters were determined: anodic transfer coefficient (alpha*n) of 1.09 and a standard heterogeneous rate constant (k°) of 1.97 x 103 s-1.
- Low Activation Energy: A low activation energy (Ea) of 17.632 kJ.mol-1 was calculated, confirming that the oxidation rate is limited by mass transport (diffusion) rather than high kinetic barriers.
- Process Acceleration: Both increased temperature (up to 353 K) and the presence of chloride ions (Cl-) significantly accelerate the OXA oxidation rate, indicating favorable conditions for industrial application in various water matrices.
- Analytical Utility: A strong linear correlation (R2 = 0.9959) between peak current density and OXA concentration confirms BDDâs potential for robust quantitative determination of antibiotics in environmental and pharmaceutical samples.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Electrode Material | Boron-doped Diamond (BDD) | N/A | Produced via HF-CVD |
| BDD Film Thickness | ~1 | ”m | Final deposited layer |
| BDD Growth Rate | 0.24 | ”m.h-1 | HF-CVD process parameter |
| Substrate Resistivity | 1-3 | mΩ.cm | p-Si wafers |
| Working Electrode Area | 1 | cm2 | Apparent exposed area |
| Supporting Electrolyte | 0.1 | M | Potassium Sulfate (K2SO4) |
| Potential Scan Rate Range | 5 to 100 | mV.s-1 | Cyclic Voltammetry study |
| Anodic Transfer Coefficient (alpha*n) | 1.09 | Dimensionless | Irreversible process calculation |
| Number of Electrons (n) | ~2.18 | Dimensionless | Estimated transfer phenomenon |
| Standard Heterogeneous Rate Constant (k°) | 1.97 x 103 | s-1 | Calculated via Lavironâs equation |
| Activation Energy (Ea) | 17.632 | kJ.mol-1 | Indicates diffusion control (less than 40 kJ.mol-1) |
| Temperature Range | 298 to 353 | K | Temperature variation study |
| Chloride Ion Concentration Range | 20 to 100 | mM | KCl addition study |
| Quantitative Linearity (R2) | 0.9959 | Dimensionless | Peak current density vs. OXA concentration |
Key Methodologies
Section titled âKey MethodologiesâThe study utilized Cyclic Voltammetry (CV) on custom-fabricated BDD electrodes to investigate the electrochemical kinetics of Oxacillin (OXA) oxidation.
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BDD Electrode Fabrication (HF-CVD):
- BDD films were grown on low resistivity (1-3 mΩ.cm) p-Si wafers using Hot-Filament Chemical Vapor Deposition (HF-CVD).
- The process gas mixture consisted of 1% CH4 in H2, doped with trimethylboron to achieve boron incorporation.
- The resulting BDD film thickness was approximately 1 ”m, grown at a rate of 0.24 ”m.h-1.
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Electrochemical Setup:
- A standard three-electrode cell (100 mL) was used, connected to an Autolab PGStat 20 potentiostat.
- The BDD served as the Working Electrode (1 cm2), Platinum wire as the Counter Electrode, and Saturated Calomel Electrode (SCE) as the Reference Electrode. All potentials are reported versus SCE.
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Electrode Pretreatment:
- Prior to experiments, the BDD surface was cleaned and activated in 0.5 mol/L H2SO4.
- Pretreatment sequence: Anodic pre-treatment (+2 V for 15 s) followed by cathodic pre-treatment (-2 V for 90 s) to remove impurities and convert the surface primarily to hydrogen termination.
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Voltammetric Analysis:
- Experiments were conducted in 0.1 M K2SO4 supporting electrolyte.
- Parameters systematically varied included: OXA concentration (0.62 to 3.74 mM), potential scan rate (5 to 100 mV.s-1), temperature (298 K to 353 K), and chloride ion concentration (up to 100 mM KCl).
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Kinetic Modeling:
- The mechanism (adsorption-diffusion) was determined by plotting peak current density (jp) against the square root of the scan rate (v1/2) and log jp against log v.
- Kinetic constants (E°, k°, alpha*n, Ea) were calculated using the linear dependence of peak potential (Ep) on log v, applying the Laviron equation for irreversible processes.
Commercial Applications
Section titled âCommercial ApplicationsâThe findings support the application of BDD technology in high-performance electrochemical systems, particularly those dealing with environmental remediation and chemical sensing.
- Wastewater Treatment (Pharmaceuticals):
- Antibiotic Degradation: Direct application in Advanced Oxidation Processes (AOPs) for mineralizing persistent organic pollutants (POPs) like Oxacillin in hospital and municipal wastewater streams.
- Robust Anodes: BDDâs stability and resistance to passivation (confirmed by stirring experiments) make it ideal for long-term use in industrial electrochemical reactors, especially for high-volume effluent treatment.
- Electrochemical Sensing and Monitoring:
- Quantitative Analysis: Use as a highly sensitive and stable sensor platform for the quantitative determination of drug residues in complex matrices, including pharmaceutical quality control and environmental monitoring (surface water, groundwater).
- Process Control: Integration into treatment plants to monitor the real-time concentration and degradation kinetics of contaminants.
- Chlorine-Mediated Processes:
- Saline Water Treatment: The observed acceleration of oxidation in the presence of chloride ions makes BDD highly effective for treating brackish water or industrial effluents where chlorine species are present or generated, leveraging indirect oxidation pathways.
View Original Abstract
The effectiveness of electrochemical techniques in preventing and resolving wastewater contamination issues has been demonstrated. However, this method requires knowledge of the organic pollutant's (Oxacillin: OXA) electrochemical behavior before electrolysis. The aim of this study is to enhance comprehension of the electrochemical process of oxacillin oxidation on the non-active boron-doped diamond (BDD) electrode. These electrochemical properties, focusing on phenomena at the electrode/electrolyte interface, were analyzed by cyclic voltammetry. Effects of concentration of oxacillin, potential scan rate, number of potential scanning cycles, temperature and chloride ions that were investigated allowed for the acquisition of some parameters. This study showed that BDD electrode can be used to quantitatively determine the presence of this substrate in medicines and environmental samples. The process is irreversible and diffusion controlled and proceed in two ways: an indirect oxidation mediated by in situ oxidative species and a direct electron transfer at the surface of the boron-doped diamond electrode. Parameters of OXA electrooxidation, such as anodic transfer coefficient, heterogenous rate constant and activation energy were estimated as 1.09, 1.97Ă10<sup>3</sup> s<sup>-1</sup> and 17.632kJ mol<sup>-1</sup>. The increase in temperature and the presence of chloride ions promote oxidation of OXA. This indicates electrochemical conditions adequate to oxidize oxacillin on boron-doped diamond anode.