Degradation of refractory compounds in industrial wastewaters by advanced technologies based on electrochemical and photochemical oxidation
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-11-21 |
| Journal | Global NEST International Conference on Environmental Science & Technology |
| Authors | Konstantinos V. Plakas, Panagiota Petsi, Vasilios Sarasidis, A.J. Karabelas |
| Institutions | Centre for Research and Technology Hellas |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Advanced Oxidation using Boron-Doped Diamond (BDD)
Section titled âTechnical Documentation & Analysis: Advanced Oxidation using Boron-Doped Diamond (BDD)âExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates the efficacy of Advanced Oxidation Processes (AOPs), particularly utilizing Boron-Doped Diamond (BDD) Anodic Oxidation (AO), for the mineralization of highly refractory organic pollutants in industrial wastewater.
- Core Achievement: Achieved rapid and near-complete mineralization of high-load pesticide wastewater (TOC 800-1820 mg/L) using BDD-based electrochemical methods.
- Material Validation: BDD was confirmed as the optimal anode material due to its exceptionally high O2 overpotential, maximizing the heterogeneous electrogeneration of highly reactive hydroxyl radicals (â˘OH).
- Performance Metrics: The combined AO/H2O2/UV-C process yielded the fastest Total Organic Carbon (TOC) abatement rate, reaching 534 mgC/h.
- Process Optimization: System efficiency was significantly improved by increasing the wastewater flow rate (up to 1400 mL/min), which reduced ohmic resistance and enhanced mass transfer to the BDD anode surface.
- Industrial Relevance: The study utilized bench-scale, galvanostatic conditions and âon-lineâ dosing of H2O2, providing a clear pathway for scaling the hybrid BDD-based EAOP for practical industrial applications.
- 6CCVD Relevance: The success of this study hinges entirely on the performance and stability of the BDD electrode, a core material manufactured and customized by 6CCVD.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the electrochemical and combined oxidation experiments:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Anode Material | Boron-Doped Diamond (BDD) | N/A | Optimal for high O2 overpotential |
| Initial TOC Concentration | 800 - 1820 | mg/L | Pesticide wastewater feedstock |
| Initial COD Concentration | 1398 - 7400 | mg/L | Pesticide wastewater feedstock |
| Current Density (AO Only) | 100 | mA/cm2 | Highest tested (Exp. No 6) |
| Current Density (Combined AO) | 77 | mA/cm2 | Used in the fastest combined process |
| Recirculation Flow Rate (AO) | 1400 | mL/min | Optimized flow rate for mass transfer |
| TOC Removal Rate (AO Only) | 36.4 | mgC/h | At 100 mA/cm2 |
| TOC Removal Rate (H2O2/UV-C) | 369 | mgC/h | At 11.8 W/L UV dose |
| TOC Removal Rate (Combined) | 534 | mgC/h | Fastest abatement rate achieved |
| Color Removal (H2O2/UV-C) | >98 | % | Achieved after 4h treatment |
| Total Treatment Volume (Combined) | 5 | L | Bench-scale total volume |
Key Methodologies
Section titled âKey MethodologiesâThe experimental investigation focused on bench-scale Advanced Oxidation Processes (AOPs) using a specialized electrochemical cell.
- Wastewater Preparation: Real wastewater from a pesticides manufacturing plant was pre-treated using a 1.5 Âľm glass fiber filter to remove suspended particles and prevent electrode deposition.
- Electrochemical Setup (AO): A plate-and-frame Micro Flow Cell was employed, featuring a Boron-Doped Diamond (BDD) electrode as the anode and a Nickel mesh Gas Diffusion Electrode (GDE-Ni) as the cathode.
- Operating Mode: Experiments were conducted under galvanostatic conditions (constant current density) with total test durations varying from 2h up to 24h.
- Parameter Variation: Key operating variables investigated included current density (20 to 100 mA/cm2), recirculation flow rate (60 to 1400 mL/min), and the presence of supporting electrolyte (Na2SO4).
- Photochemical Setup (H2O2/UV-C): Low-pressure mercury-vapor lamps (253.7 nm) were housed in quartz sleeves within a stainless steel photoreactor. H2O2 was added in a single âbatchâ dose for standalone tests.
- Combined Hybrid Process: The AO effluent was driven directly into the photoreactor. H2O2 was added via a dosing pump âon-lineâ at a constant rate (up to 15.7 g/L H2O2), simulating continuous industrial operation.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful implementation of Electrochemical Advanced Oxidation Processes (EAOPs) relies fundamentally on high-quality, high-performance Boron-Doped Diamond (BDD) electrodes. 6CCVD is the global leader in supplying custom MPCVD diamond materials necessary to replicate, optimize, and scale this research.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research, the primary material requirement is high-quality, stable BDD.
- Heavy Boron Doped PCD (Polycrystalline Diamond): This is the ideal material for large-area electrochemical flow cells and industrial scale-up. 6CCVD provides PCD wafers up to 125mm in diameter, offering the necessary surface area and mechanical robustness for high-flow, high-current density applications (up to 100 mA/cm2).
- Boron Doped SCD (Single Crystal Diamond): For highly specialized micro-reactor designs or fundamental research requiring ultra-low defect density and precise doping profiles, 6CCVD offers SCD plates up to 500Âľm thick.
- Surface Finish: 6CCVD guarantees polishing to Ra < 5nm for inch-size PCD, ensuring optimal surface morphology for consistent electrogeneration of â˘OH radicals and minimizing fouling.
Customization Potential
Section titled âCustomization PotentialâThe study utilized a specific plate-and-frame cell design, requiring custom electrode geometry. 6CCVDâs in-house capabilities directly address these needs:
| Requirement in Paper | 6CCVD Customization Capability | Benefit to Researcher/Engineer |
|---|---|---|
| Specific Flow Cell Dimensions | Custom dimensions and laser cutting | Supply of BDD plates/wafers precisely matched to existing reactor geometry (e.g., Micro Flow Cell). |
| High Current Density Contacts | Internal Metalization Services | Application of robust contact layers (Au, Pt, Ti, W) for reliable, long-term operation at high current densities (up to 100 mA/cm2). |
| Large Scale-Up | Plates/wafers up to 125mm (PCD) | Enables transition from bench-scale (500 mL) to pilot or industrial scale reactors without compromising material quality. |
| Surface Quality | Polishing to Ra < 5nm (PCD) | Ensures uniform current distribution and maximizes active surface area for mass transfer enhancement. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in the material science of diamond for electrochemical applications. We offer comprehensive support for projects involving:
- Material Selection: Guidance on choosing the optimal BDD doping level and crystal structure (SCD vs. PCD) based on target current density and wastewater matrix.
- Electrode Design: Consultation on substrate preparation, metal contact placement, and integration into complex flow cell architectures (e.g., plate-and-frame or cylindrical reactors).
- Process Optimization: Assistance in understanding how diamond surface properties influence the kinetics of hydroxyl radical generation for specific EAOPs/Wastewater Treatment projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. Global shipping (DDU default, DDP available) ensures rapid delivery to research facilities worldwide.
View Original Abstract
Results are presented of a systematic experimental investigation aiming to eliminate refractory organics from industrial effluents, of high and non-biodegradable organic load, by two Advanced Oxidation Processes (AOPs). Bench scale experiments were performed with real wastewater samples collected from a pesticides manufacturing plant, of varying TOC content (800-1820 mg/L), to investigate the effectiveness of boron-doped diamond (BDD) anodic oxidation (AO), of H2O2 photolysis with UV-C irradiation (H2O2/UV-C), and their combination (i.e. AO/H2O2/UV-C) on the total organic carbon (TOC) removal. The effect of main operating conditions was investigated for both processes, separately and in combination. In the case of AO, TOC and COD were removed at a rate of 36.4 mgC/h and 89.5 mgO2/L, by applying a current density of 100 mA/cm2 and a recirculation flow rate of 1400 mL/min. The H2O2/UV-C process achieved a TOC removal rate of 369 mgC/h and over 98% color removal after 4 h of treatment, when a single dose of 6 g/L H2O2 and 11.8 W/L of UVC irradiation dose were applied. Finally, the combined process (AO/H2O2/UV-C) led to a faster TOC abatement (534 mgC/h) and a higher color removal, after treating the wastewater with 77 mA/cm2 current density, 5.9 W/L UVC irradiation dose and âon-lineâ dosing 15.7 g/L H2O2.