Electrooxidation of Diclofenac in Synthetic Pharmaceutical Wastewater Using an Electrochemical Reactor Equipped with a Boron Doped Diamond Electrode
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-10-12 |
| Journal | Journal of the Mexican Chemical Society |
| Authors | Gabriela Coria, José L. Nava, Gilberto Carreño |
| Institutions | Universidad de Guanajuato |
| Citations | 12 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: High-Efficiency Electrochemical Wastewater Treatment using Boron-Doped Diamond (BDD)
Section titled âTechnical Documentation & Analysis: High-Efficiency Electrochemical Wastewater Treatment using Boron-Doped Diamond (BDD)âExecutive Summary
Section titled âExecutive SummaryâThis research validates the exceptional performance of Boron-Doped Diamond (BDD) electrodes in advanced oxidation processes (AOPs) for the complete mineralization of persistent pharmaceutical contaminants (Diclofenac).
- 100% Mineralization Achieved: Complete degradation of 150 mg L-1 Diclofenac was realized in an FM01-LC flow reactor, achieving 100% Chemical Oxygen Demand (COD) removal.
- High Current Efficiency: Optimal performance yielded a high current efficiency of 78%, demonstrating efficient utilization of applied current for contaminant destruction rather than parasitic reactions.
- Hydroxyl Radical Dominance: The use of an inert perchlorate (NaClO4) supporting electrolyte confirmed that the degradation mechanism was driven primarily by the potent hydroxyl radicals (âąOH) electrogenerated on the BDD anode surface.
- Optimized Flow Regime: The study identified an optimal mean linear fluid velocity (29.2 cm s-1) and current density (15 mA cm-2) that maximized mineralization efficiency and minimized energy consumption (2.54 kWh m-3).
- Critical Material Requirement: Success hinged on using high-quality BDD electrodes capable of operating within the high anodic potential window (2.3 V †E †2.75 V vs. SHE) necessary to maximize âąOH production.
- 6CCVD Advantage: 6CCVD specializes in providing the precise 2-D BDD plate geometries and thin-film architectures on conductive substrates (like Ti) required for scaling up this high-efficiency electrochemical incineration process.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Contaminant Concentration (Initial) | 150 | mg L-1 | Diclofenac |
| Initial COD (Chemical Oxygen Demand) | 320-330 | mg L-1 | Synthetic Wastewater |
| Electrode Material (Anode) | BDD (Boron Doped Diamond) | Material | 2-D Plate on Ti support |
| BDD Thickness | 2-7 | ”m | Supported on Ti |
| Reactor Type | FM01-LC | Model | Filter Press Flow Reactor |
| Electrode Area (ABDD) | 64 | cm2 | 16 cm (L) x 4 cm (B) |
| Optimal Current Density ($j$) | 15 | mA cm-2 | Maximized degradation rate |
| Optimal Flow Velocity ($u$) | 29.2 | cm s-1 | Maximized current efficiency |
| Hydroxyl Radical Formation Potential Range | 2.3-2.75 | V vs. SHE | Required potential for BDD(*OH) production |
| Final Mineralization | 100 | % | Complete COD removal |
| Maximum Current Efficiency ($\Phi$) | 78 | % | Achieved at optimal $j$ and $u$ |
| Energy Consumption (Ec) | 2.54 | kWh m-3 | Achieved at optimal conditions for 100% removal |
| Supporting Electrolyte | 0.5 M NaClO4 | Concentration | Used to ensure inert medium |
| pH / Temperature | 6.5 / 298 | K | Neutral pH (Laboratory conditions) |
| Cell Voidage ($\varepsilon$) | 0.83 | Ratio | Reactor geometry specification |
Key Methodologies
Section titled âKey MethodologiesâThe electrooxidation of Diclofenac utilized a controlled electrochemical flow reactor (FM01-LC) setup to study the influence of current density and hydrodynamic conditions on BDD performance.
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Electrode Preparation and Stabilization:
- The BDD electrode surface was stabilized using anodic polarization (chronoamperogram) in 1 M HClO4 solution.
- Cleaning was performed at a current density of 10 mA cm-2 for 30 minutes to remove trace pollutants and ensure reproducible results.
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Microelectrolysis Studies (Determining BDD Potential Window):
- Linear sweep voltammetry (20 mV s-1 scan rate) was performed in a three-electrode cell (BDD working electrode, SCE reference, vitreous carbon counter) using a rotating disk electrode (RDE).
- This testing determined the critical anodic potential range (2.3 V to 2.75 V vs. SHE) required for the preferential formation of hydroxyl radicals (BDD(*OH)) over oxygen evolution.
- Tafel curve analysis was used to confirm that the selected potential range favored water oxidation (âąOH radical formation) and was not mass transport limited.
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Flow Reactor Implementation (FM01-LC):
- The undivided FM01-LC reactor was constructed with a 64 cm2 BDD anode (plate, 2-7 ”m thick on Ti) and a stainless steel cathode plate, separated by a 0.55 cm spacer.
- Experiments were conducted by varying the applied current density ($j$: 10, 15, and 20 mA cm-2) and mean linear fluid velocity ($u$: 14.6 to 58.4 cm s-1).
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Performance Monitoring:
- Diclofenac degradation was tracked using UV-visible spectrophotometry ($\lambda$ = 276 nm).
- Overall mineralization was monitored using Chemical Oxygen Demand (COD) analysis via the closed reflux dichromate titration method.
- Integral current efficiency and energy consumption (kWh m-3) were calculated based on COD removal rates.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is an industry-leading supplier of high-performance CVD diamond materials, perfectly positioned to support the replication, scaling, and commercial deployment of BDD-based Advanced Oxidation Processes (AOP) demonstrated in this research.
Applicable Materials
Section titled âApplicable MaterialsâThe successful implementation of this electrochemical treatment relies critically on the quality and robustness of the BDD electrode. 6CCVD offers application-optimized materials:
| Material Specification | Requirement for Diclofenac Oxidation | 6CCVD Capability & Solution |
|---|---|---|
| Boron-Doped Diamond (BDD) | Low charge transfer resistance, maximizing surface coverage of highly oxidative hydroxyl radicals (âąOH). | We supply Heavy Boron Doped SCD/PCD, engineered for optimum conductivity and electrochemical inertness at high anodic potentials (up to 3.0 V vs. SHE). |
| Substrate & Architecture | Thin BDD film (2-7 ”m) deposited on a robust, conductive substrate (Ti) capable of withstanding acidic pre-treatment. | 6CCVD provides custom BDD film deposition, achieving thicknesses from 0.1 ”m to 500 ”m on various substrates, including Titanium (Ti) and Tantalum. |
| Anode Geometry | Required a 2-D plate (16 cm x 4 cm = 64 cm2). | 6CCVD provides Polycrystalline Diamond (PCD) wafers up to 125mm diameter. We offer precision laser cutting services to produce custom 2-D plates or unique geometries exactly matching FM01-LC or commercial reactor specifications. |
Customization Potential for Scale-Up
Section titled âCustomization Potential for Scale-UpâThe research utilized a specific 64 cm2 BDD plate. 6CCVDâs in-house capabilities ensure seamless transition from laboratory research to commercial scale:
- Precision Sizing and Shaping: We provide custom BDD wafer and plate dimensions, ensuring precise fitting into existing filter press reactors (like the FM01-LC or commercial equivalents). Our laser cutting capabilities support complex electrode shapes without compromising diamond integrity.
- Metalization Services: While this study used stainless steel as the cathode, 6CCVD offers custom metalization (Au, Pt, Pd, Ti, W, Cu). This capability allows engineers to optimize cathode materials for specific systems, potentially enhancing hydrogen evolution reaction kinetics or minimizing parasitic side reactions.
- Surface Finish Optimization: For flow-through applications where turbulence is critical (as noted by the importance of fluid velocity $u$), 6CCVD guarantees surface quality. Our specialized polishing achieves Ra < 5 nm for inch-size PCD materials, ensuring predictable hydrodynamic profiles within the reactor channel.
Engineering Support
Section titled âEngineering SupportâThe successful optimization achieved in this paper (78% current efficiency) required careful tuning of electrochemical and hydrodynamic parameters. 6CCVDâs commitment extends beyond material supply:
- BDD Synthesis Consultation: Our in-house PhD team provides expert consultation on optimizing BDD material selection (doping concentration, film thickness, substrate selection) to maximize hydroxyl radical yield and reduce the Tafel slope, which directly impacts energy consumption and efficiency in wastewater treatment projects.
- Global Logistics: We provide global shipping (DDU default, DDP available) to ensure timely delivery of custom BDD electrodes, supporting global R&D and pilot plant schedules.
For custom specifications or material consultation related to electrochemical water treatment, BDD anodes, or other Advanced Oxidation Processes, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
This paper deals with the degradation of diclofenac by electrochemical oxidation in NaClO4 medium at neutral pH using a FM01-LC reactor equipped with a boron doped diamond electrode (BDD). Microelectrolysis studies were carried out to find the current density domain where hydroxyl radical (âąOH) formation is favored, 10 †j †20 mA cm-2. Electrolysis experiments at mean linear flow velocities of 14.6 †u †58.4 cm s-1 were performed. The experimental set-up achieved 100% diclofenac mineralization with 78% current efficiency and energy consumption of 2.54 kWh m-3 at j = 15 mA cm-2 and u=29.2 cm s-1.