Synergistic mineralization of ofloxacin in electro-Fenton process with BDD anode - Reactivity and mechanism
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-05-09 |
| Journal | Separation and Purification Technology |
| Authors | Weilu Yang, Nihal Oturan, Jialin Liang, Mehmet A. Oturan |
| Institutions | Jinan University, UniversitĂŠ Gustave Eiffel |
| Citations | 24 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Synergistic Mineralization using BDD Anodes
Section titled âTechnical Documentation & Analysis: Synergistic Mineralization using BDD AnodesâExecutive Summary
Section titled âExecutive SummaryâThis research validates the superior performance of Boron-Doped Diamond (BDD) anodes in Electro-Fenton (EF) processes for the complete mineralization of refractory organic pollutants, specifically the antibiotic Ofloxacin (OFLO).
- Synergistic Radical Generation: The EF-BDD process achieves outstanding degradation efficiency through the simultaneous generation of homogeneous hydroxyl radicals (â˘OH) in the bulk solution and highly potent heterogeneous radicals (BDD(â˘OH)) on the anode surface.
- High Mineralization Efficiency: Complete OFLO degradation (100% removal) was achieved in just 30 minutes, and 100% Total Organic Carbon (TOC) removal was reached within 6 hours under optimal conditions (8.3 mA cm-2).
- Cost Effectiveness: EF-BDD significantly reduced energy consumption (EC) for OFLO removal by 28%-41% compared to the Anodic Oxidation (AO) process, demonstrating superior cost effectiveness, particularly at low current densities.
- Kinetic Dominance: At high current densities (16.6 mA cm-2), the degradation kinetics were dominated by the heterogeneous BDD(â˘OH) radicals, proving the immense oxidative power of the diamond surface.
- High Reactivity: The absolute rate constant (kOFLO) for OFLO oxidation by â˘OH was calculated to be 3.86 x 109 M-1 s-1, confirming the rapid, non-selective nature of the diamond-catalyzed oxidation.
- Toxicity Reduction: The process successfully mineralized OFLO and its transformation products (OTPs), resulting in significantly reduced acute and developmental toxicity compared to the parent compound.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Target Pollutant | Ofloxacin (OFLO) | 0.1 mM | Initial concentration (21.6 mg L-1 TOC) |
| Anode Material | Boron-Doped Diamond (BDD) | N/A | Non-active anode, high Oâ evolution overpotential (~2.2 V/SHE) |
| Cathode Material | EEGr-CF | N/A | Electrochemically Exfoliated Graphene-based Carbon Felt |
| Electrolyte Concentration | 0.05 | M | NaâSOâ |
| Solution pH | 3 | N/A | Optimal for EF process |
| Catalyst Concentration | 0.2 | mM | Fe2+ (Ferrous ion) |
| Anode Effective Area | 24 (4 x 6) | cm2 | BDD and DSA anodes |
| Current Density Range Tested | 2.1 to 16.6 | mA cm-2 | Key variable for radical production |
| OFLO Degradation Time (100%) | 30 | min | At 8.3 mA cm-2 (EF-BDD) |
| TOC Removal Efficiency (6 h) | 100 | % | At 8.3 mA cm-2 (EF-BDD) |
| Energy Consumption (EC) | 0.8 | kWh (g TOC)-1 | At 8.3 mA cm-2 (EF-BDD) |
| Absolute Rate Constant (kOFLO) | 3.86 x 109 | M-1 s-1 | Oxidation by â˘OH |
| Synergistic Factor (SF) Range | 0.28 to -0.08 | N/A | Decreased with rising current density (4.2 to 16.6 mA cm-2) |
Key Methodologies
Section titled âKey MethodologiesâThe study utilized a single-chamber electrolytic cell to compare the performance of EF-BDD (Electro-Fenton with BDD anode), AO (Anodic Oxidation with BDD anode), and EF-DSA (Electro-Fenton with Dimensionally Stable Anode).
- Electrode Setup:
- BDD and DSA anodes had an effective surface area of 24 cm2 (4 x 6 cm).
- EEGr-CF cathodes had an area of 6 cm2 (2 x 3 cm).
- The distance between electrodes was maintained at 2 cm.
- Solution Preparation:
- Aqueous solution of 0.1 mM OFLO was used, containing 0.05 M NaâSOâ as the supporting electrolyte.
- The solution pH was adjusted to 3, which is optimal for Fenton chemistry.
- A ferrous catalyst concentration of 0.2 mM Fe2+ was selected for EF experiments.
- Operation Conditions:
- Experiments were conducted at ambient temperature.
- Aeration was provided at 0.75 L min-1 to maintain Oâ-saturated conditions, crucial for HâOâ generation on the cathode.
- Analytical Procedures:
- OFLO concentration was monitored using HPLC.
- TOC removal efficiency was measured to track complete mineralization.
- HâOâ concentration was measured spectrophotometrically.
- Mineralization Current Efficiency (MCE) and Energy Consumption (EC) were calculated using standard electrochemical equations (Eqs. 4, 5, 6).
- The absolute rate constant (kOFLO) was determined using a competition kinetic method with 4-HBA as the standard competitor.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful application of BDD anodes in this advanced oxidation process (AOP) highlights the critical role of high-quality, customized diamond materials. 6CCVD is uniquely positioned to supply the necessary Boron-Doped Diamond (BDD) electrodes required to replicate, scale, and optimize this research for industrial pharmaceutical wastewater treatment.
Applicable Materials
Section titled âApplicable Materialsâ| Research Requirement | 6CCVD Solution | Technical Advantage |
|---|---|---|
| BDD Anode Material | Heavy Boron-Doped PCD (Polycrystalline Diamond) | High doping levels ensure maximum conductivity and high Oâ evolution overpotential, maximizing BDD(â˘OH) radical generation for superior mineralization efficiency. |
| Electrode Dimensions | Custom Plates/Wafers up to 125mm | We can supply BDD plates significantly larger than the 24 cm2 used in the study, enabling direct scale-up for pilot and industrial reactors. |
| Substrate Thickness | Custom Substrates (up to 10mm) | Provides mechanical stability and thermal management necessary for high current density operation (up to 16.6 mA cm-2 and beyond). |
| Surface Quality | Polishing (Ra < 5nm for Inch-size PCD) | Ultra-smooth surfaces minimize fouling and maximize the active surface area for heterogeneous radical production, ensuring long-term stability and performance. |
Customization Potential
Section titled âCustomization PotentialâThe performance of electrochemical AOPs is highly dependent on precise electrode engineering. 6CCVD offers comprehensive customization services:
- Custom Doping Levels: We can tailor the boron concentration in the BDD film to optimize conductivity versus radical generation efficiency, balancing the production of BDD(â˘OH) and minimizing competing side reactions.
- Precision Fabrication: We offer advanced laser cutting and shaping services to produce electrodes with specific geometries required for flow cells, stack reactors, or specific current density requirements (e.g., 4 x 6 cm2 or larger custom shapes).
- Metalization Services: While the paper focuses on the BDD surface, robust electrical contacts are essential. 6CCVD provides internal metalization capabilities (Au, Pt, Pd, Ti, W, Cu) for creating durable, low-resistance contacts necessary for high-current applications.
Engineering Support
Section titled âEngineering SupportâThe research demonstrates a complex trade-off between homogeneous (â˘OH) and heterogeneous (BDD(â˘OH)) radical contributions, which shifts based on current density.
- 6CCVDâs in-house PhD team specializes in diamond electrochemistry and can assist researchers and engineers in selecting the optimal BDD material specifications (doping concentration, film thickness, and substrate choice) to maximize the synergistic effect for similar Pharmaceutical Wastewater Treatment projects.
- We provide global shipping (DDU default, DDP available) to ensure rapid delivery of custom BDD anodes worldwide, supporting time-sensitive research and development cycles.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
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