Electrochemical degradation of surfactants in domestic wastewater using a DiaClean® cell equipped with a boron-doped diamond electrode
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2023-04-25 |
| Journal | Frontiers in Chemistry |
| Authors | Dayana G. Cisneros-León, Patricio J. Espinoza-Montero, Diego Bolaños-Méndez, Jocelyne Álvarez-Paguay, Lenys Fernández |
| Institutions | Central University of Ecuador, Pontificia Universidad Católica del Ecuador |
| Citations | 9 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: MPCVD BDD for Advanced Electro-Oxidation (AEO)
Section titled “Technical Documentation & Analysis: MPCVD BDD for Advanced Electro-Oxidation (AEO)”Source Paper: Electrochemical degradation of surfactants in domestic wastewater using a DiaClean® cell equipped with a boron-doped diamond electrode (Front. Chem., 2023)
Executive Summary
Section titled “Executive Summary”This research validates the high efficiency of Boron-Doped Diamond (BDD) electrodes manufactured via MPCVD for Advanced Electro-Oxidation (AEO) in treating complex domestic wastewater containing high surfactant loads.
- Core Achievement: Successful electrochemical degradation of surfactants and organic pollutants using a BDD anode in a commercial recirculation cell (DiaClean®).
- Material Specification: The study utilized a BDD film (1-10 µm thickness) deposited on a silicon substrate with a low resistance of 0.1 Ω cm, confirming the necessity of high-quality MPCVD BDD for robust AEO.
- Optimal Performance: Best results were achieved at a low flow rate (1.5 L min⁻¹) and moderate current density (14 mA cm⁻²).
- Pollutant Removal: Demonstrated significant removal efficiencies, including 64.7% surfactant degradation, 48.7% Chemical Oxygen Demand (COD) removal, and 44.9% Total Organic Carbon (TOC) mineralization over 7 hours.
- Economic Viability: The process exhibited a low operational cost of 1.40 USD m⁻³ (corresponding to 2.59 kW h m⁻³ energy consumption), positioning BDD-AEO as a cost-effective solution.
- Toxicity Challenge: The study highlighted that the formation of highly oxidizing reactive species (HORS) during electrolysis, while effective for degradation, resulted in post-treatment toxicity to Chlorella sp. microalgae, necessitating precise control over BDD properties.
Technical Specifications
Section titled “Technical Specifications”The following hard data points were extracted from the optimal operating conditions and results reported in the study:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Anode Material | Boron-Doped Diamond (BDD) | N/A | Deposited on Silicon Substrate |
| BDD Film Thickness | 1-10 | µm | Used in DiaClean® cell |
| Anode Surface Area | 70 | cm² | Geometric circular surface |
| Anode Resistance | 0.1 | Ω cm | BDD/Si substrate |
| Optimal Current Density (j) | 14 | mA cm⁻² | For maximum removal efficiency |
| Optimal Flow Rate (Q) | 1.5 | L min⁻¹ | Recirculation system |
| Electrolysis Time (t) | 7 | h | Total treatment duration |
| Max Surfactant Removal | 64.7 | % | At optimal conditions |
| Max COD Removal | 48.7 | % | At optimal conditions |
| Max TOC Mineralization | 44.9 | % | At optimal conditions |
| Operational Cost | 1.40 | USD m⁻³ | Based on 0.063 USD kWh⁻¹ |
| Energy Consumption | 2.59 | kW h m⁻³ | Under optimal conditions |
| Temperature Increase (ΔT) | 11.6 | °C | From 13.2 °C (initial) to 24.8 °C (final) |
Key Methodologies
Section titled “Key Methodologies”The electrochemical degradation was performed under galvanostatic conditions using a recirculation system.
- Electrochemical Cell: A commercial DiaClean® cell was utilized, coupled to a peristaltic pump and a GW INSTEK galvanostat (model SPS-3610).
- Anode Configuration: BDD disk electrode (1-10 µm BDD thickness on silicon, 0.1 Ω cm resistance) with a 70 cm² geometric circular surface, acting as the anode.
- Cathode Configuration: T304 Stainless Steel (SS) electrode with a 70 cm² geometric circular surface, acting as the cathode.
- Electrode Pre-treatment: Electrodes were cleaned with 0.1 M H2SO4 and subjected to 2 A current for 15 minutes to remove surface impurities.
- Flow Rate Study: The effect of recirculation flow was tested at 1.5, 4.0, and 7.0 L min⁻¹ (constant j = 14 mA cm⁻²).
- Current Density Study: The effect of current density was tested at 7, 14, 20, 30, 40, and 50 mA cm⁻² (constant Q = 1.5 L min⁻¹).
- Analytical Monitoring: Efficiency was monitored by analyzing Surfactant concentration (HACH 8028 crystal violet method), COD (USEPA HACH 8000), and TOC (Standard Methods 5310-C).
- Ecotoxicity Test: Toxicity was assessed by monitoring the cellular density of Chlorella sp. microalgae in treated wastewater over a 30-day period.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”6CCVD is the expert supplier of MPCVD diamond materials required to replicate, scale, and optimize the Advanced Electro-Oxidation (AEO) process demonstrated in this research. We provide the high-quality, low-resistance BDD necessary for efficient electrocatalysis.
Applicable Materials for AEO Research
Section titled “Applicable Materials for AEO Research”The success of this study hinges on the quality and specific properties of the BDD anode. 6CCVD offers materials tailored for high-performance electrochemical applications:
- Heavy Boron-Doped SCD/PCD (BDD) Wafers: We supply BDD films grown directly on silicon substrates, matching the configuration used in the DiaClean® cell. Our BDD material ensures the low resistivity (0.1 Ω cm or better) required for high current density operation and minimal energy loss.
- Custom Thickness Control: The paper utilized a BDD thickness between 1 µm and 10 µm. 6CCVD provides precise thickness control for both Single Crystal Diamond (SCD) and Polycrystalline Diamond (PCD) BDD films, ranging from 0.1 µm up to 500 µm, allowing researchers to fine-tune electrode lifespan and performance.
Customization Potential & Scaling
Section titled “Customization Potential & Scaling”The DiaClean® cell used a 70 cm² circular BDD disk. 6CCVD’s manufacturing capabilities enable immediate scaling and customization for pilot and industrial applications:
| Requirement from Paper | 6CCVD Capability | Advantage for Replication/Scaling |
|---|---|---|
| BDD Dimensions (70 cm² circular disk) | Custom Plates/Wafers up to 125mm (PCD) | Enables production of larger, high-throughput electrodes for industrial scale-up. |
| BDD Thickness (1-10 µm) | SCD and PCD thickness control (0.1 µm - 500 µm) | Precise control over the active layer thickness for optimizing cost vs. electrode lifetime. |
| Metalization (For electrical contact) | In-house Metalization Services (Au, Pt, Pd, Ti, W, Cu) | Ensures robust, low-resistance electrical contacts necessary for high-current density AEO systems. |
| Polishing (Surface Finish) | Polishing to Ra < 5nm (Inch-size PCD) | Provides a smooth, uniform surface finish, critical for consistent mass transfer and current distribution in flow cells. |
Engineering Support for Toxicity Mitigation
Section titled “Engineering Support for Toxicity Mitigation”The research noted that the AEO process generated toxic HORS (e.g., Cl₂, HClO, C₂O₄²⁻), inhibiting microalgae growth. This is a common challenge in wastewater treatment requiring advanced material engineering.
- Process Optimization: 6CCVD’s in-house PhD team specializes in material selection and optimization for similar Electrochemical Water Treatment projects. We assist clients in tuning the BDD material properties (specifically boron concentration and surface termination) to selectively favor the generation of desired HORS (like hydroxyl radicals, OH) while suppressing the formation of unwanted toxic species (like active chlorine species) in complex matrices.
- Material Selection: We provide consultation on whether SCD BDD or PCD BDD is best suited for specific wastewater compositions to maximize mineralization efficiency while minimizing post-treatment toxicity.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Treating domestic wastewater has become more and more complicated due to the high content of different types of detergents. In this context, advanced electro-oxidation (AEO) has become a powerful tool for complex wastewater remediation. The electrochemical degradation of surfactants present in domestic wastewater was carried out using a DiaClean ® cell in a recirculation system equipped with boron-doped diamond (BDD) as the anode and stainless steel as the cathode. The effect of recirculation flow (1.5, 4.0 and 7.0 L min −1 ) and the applied current density (j = 7, 14, 20, 30, 40, and 50 mA cm −2 ) was studied. The degradation was followed by the concentration of surfactants, chemical oxygen demand (COD), and turbidity. pH value, conductivity, temperature, sulfates, nitrates, phosphates, and chlorides were also evaluated. Toxicity assays were studied through evaluating Chlorella sp . performance at 0, 3, and 7 h of treatment. Finally, the mineralization was followed by total organic carbon (TOC) under optimal operating conditions. The results showed that applying j = 14 mA cm −2 and a flow rate of 1.5 L min −1 during 7 h of electrolysis were the best conditions for the efficient mineralization of wastewater, achieving the removal of 64.7% of surfactants, 48.7% of COD, 24.9% of turbidity, and 44.9% of mineralization analyzed by the removal of TOC. The toxicity assays showed that Chlorella microalgae were unable to grow in AEO-treated wastewater (cellular density: 0 × 10 4 cells ml −1 after 3- and 7-h treatments). Finally, the energy consumption was analyzed, and the operating cost of 1.40 USD m −3 was calculated. Therefore, this technology allows for the degradation of complex and stable molecules such as surfactants in real and complex wastewater, if toxicity is not taken into account.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
Section titled “References”- 2017 - Electrochemical degradation of nonylphenol ethoxylate-7 (NP7EO) using a DiaClean® cell equipped with boron-doped diamond electrodes (BDD) [Crossref]
- 2018 - Standard Methodds for The Examination Of Water and Wastewater
- 2018 - Integrated advanced oxidation process, ozonation-electrodegradation treatments, for nonylphenol removal in batch and continuous reactor [Crossref]
- 2009 - Electro-fenton process and related electrochemical technologies based on fenton’s reaction chemistry [Crossref]
- 2019 - Boron-doped diamond for hydroxyl radical and sulfate radical anion electrogeneration, transformation, and voltage-free sustainable oxidation [Crossref]
- 2005 - Electrochemical synthesis of peroxodiphosphate using boron-doped diamond anodes [Crossref]
- 2016 - Use of DiaCell modules for the electro-disinfection of secondary-treated wastewater with diamond anodes [Crossref]
- 2014 - Microbial characterization and degradation of linear alkylbenzene sulfonate in an anaerobic reactor treating wastewater containing soap powder [Crossref]