Effect of Electrode Type on Bacteria Removal and Chlorine and Radical Production in Electrochemical Water Disinfection
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-09-15 |
| Journal | Deu Muhendislik Fakultesi Fen ve Muhendislik |
| Authors | Emine Esra Gerek, AyĆe Tansu Koparal, Ali SavaĆ Koparal |
| Institutions | Anadolu University, EskiĆehir City Hospital |
| Analysis | Full AI Review Included |
Technical Analysis and Documentation: Electrochemical Water Disinfection using Diamond Electrodes
Section titled âTechnical Analysis and Documentation: Electrochemical Water Disinfection using Diamond ElectrodesâSource Paper: GEREK E.E., TANSU KOPARAL A., KOPARAL A.S. (2021). Effect of Electrode Type on Bacteria Removal with Chlorine and Radical Production in Electrochemical Water Disinfection. DEĂFMD 23(69), 787-801.
Executive Summary
Section titled âExecutive SummaryâThis research validates Boron-Doped Diamond (BDD) electrodes as the optimal material for electrochemical water disinfection, achieving a critical balance between high efficacy and minimal toxic byproduct formation.
- Superior Performance: BDD electrodes achieved disinfection efficiency comparable to Iridium Metal-Oxide (IrOx) electrodes, eliminating 105 cfu/ml of E. coli within minutes in real groundwater samples.
- Reduced Byproducts: BDD produced significantly lower concentrations of excess oxidants (Chlorine and Hydrogen Peroxide equivalent) compared to IrOx, making the treated water safer for drinking or discharge into aquatic environments.
- Ideal Compromise: BDD is identified as the ideal compromise electrode, offering high disinfection rates while generating radicals at levels closer to low-cost Graphite plates, but with vastly superior germicidal action.
- Key Mechanism: Disinfection success is positively correlated with increased current density (up to 30 mA/cm2) and higher flow rates (150 ml/min), which enhance mass transfer of active chemicals from the electrode surface.
- Application Focus: The study confirms the viability of BDD technology for scaling up groundwater disinfection systems, addressing contamination from urban and industrial wastes.
Technical Specifications
Section titled âTechnical SpecificationsâComparative performance data for the continuous flow system at the optimal current density (30 mA/cm2) and flow rate (150 ml/min).
| Parameter | BDD Electrode Value | IrOx Electrode Value | Graphite Electrode Value | Context |
|---|---|---|---|---|
| Initial Bacteria Concentration | 105 | 105 | 105 | E. coli (CFU/mL) |
| Final Bacteria Concentration | 5 | 1 | 10 | After disinfection (CFU/mL) |
| Current Density Applied | 30 | 30 | 30 | (mA/cm2) |
| Flow Rate Tested (Optimal) | 150 | 150 | 150 | (ml/min) |
| Total Chlorine Produced | 0.833 | 4.2 | 0.173 | (mg/L) - Excess oxidant |
| Total Oxidizers Produced (H2O2 Equiv.) | 30 | 90 | 130 | (mg/L) - Radical production |
| Electrode Dimensions | 4.5 x 3.1 | 4.5 x 3.1 | 4.5 x 3.1 | (cm) - Completely submerged |
| Final pH Range | 7.2 - 7.4 | 7.2 - 7.4 | 7.2 - 7.4 | Stable during electrolysis |
| Groundwater Conductivity | 700 - 900 | 700 - 900 | 700 - 900 | (”s/cm) |
Key Methodologies
Section titled âKey MethodologiesâThe experiment utilized a parallel-plate electrochemical reactor setup to compare electrode performance in both recursive (batch) and continuous flow modes using real groundwater contaminated with E. coli.
- Water Source and Contamination: Real groundwater samples (EskiĆehir, Turkey) were analyzed (pH 7.8, Conductivity 700-900 ”s/cm, Cl- 50 mg/L) and deliberately contaminated with E. coli (ATCC 25922) to achieve an initial concentration of approximately 105 cfu/ml.
- Electrode Configuration: Three electrode types (BDD, IrOx, Graphite) were tested. Anode and cathode were of the same material, configured as parallel plates (4.5 cm x 3.1 cm).
- Electrochemical Parameters: Experiments were conducted across three current densities (10, 20, and 30 mA/cm2) and three flow rates (50, 100, and 150 ml/min).
- Disinfection Measurement: Bacterial concentration was determined using a standard plaque counting method on Nutrient agar, with samples collected at 2-minute intervals.
- Byproduct Monitoring: Chlorine concentration was measured spectrophotometrically using the DPD method. Total Oxidizer (Radical) production was measured spectrophotometrically at 352 nm and expressed as Hydrogen Peroxide equivalent.
- Optimal Conditions: The highest disinfection rates were observed at the maximum tested current density (30 mA/cm2) and flow rate (150 ml/min), attributed to enhanced mass transfer and faster regeneration of active sites.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe research confirms that Boron-Doped Diamond (BDD) is the material of choice for advanced electrochemical disinfection systems requiring high efficiency and low toxic byproduct formation. 6CCVD is uniquely positioned to supply the high-quality, scalable BDD materials necessary to transition this successful lab-scale research into industrial applications.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate and scale the superior performance demonstrated in this study, 6CCVD recommends the following materials:
| 6CCVD Material | Description & Application | Key Advantage for Disinfection |
|---|---|---|
| Heavy Boron-Doped PCD | Polycrystalline Diamond (PCD) with high Boron concentration for maximum conductivity and radical generation efficiency. | Scalability: Available in large plates/wafers up to 125mm, ideal for high-throughput continuous flow reactors. |
| Heavy Boron-Doped SCD | Single Crystal Diamond (SCD) for applications requiring ultra-low defect density and extreme surface smoothness (Ra < 1nm). | Longevity & Purity: Offers maximum stability and resistance to fouling/wear in harsh electrochemical environments. |
| Custom BDD Substrates | Diamond substrates up to 10mm thick, providing robust mechanical support for high-power density applications. | Mechanical Integrity: Ensures long operational life under high current loads and turbulent flow conditions. |
Customization Potential for Industrial Scale-Up
Section titled âCustomization Potential for Industrial Scale-UpâThe study utilized small, 4.5 cm x 3.1 cm parallel plates. Scaling this technology requires larger electrodes and specialized integration features, which 6CCVD provides as standard services:
- Large-Area Electrodes: 6CCVD manufactures BDD plates up to 125mm in diameter (PCD), enabling the construction of high-capacity parallel plate reactors necessary for industrial water treatment volumes.
- Custom Dimensions and Thickness: We provide BDD wafers/plates in custom dimensions and thicknesses ranging from 0.1 ”m to 500 ”m (active layer), and substrates up to 10 mm, precisely matching reactor geometry requirements.
- Advanced Metalization: For robust electrical contact and integration into reactor cells, 6CCVD offers in-house metalization services including Ti/Pt/Au, W, Cu, and Pd contacts, ensuring low resistance and high durability.
- Surface Engineering: While the paper did not specify surface roughness, 6CCVD offers precision polishing (Ra < 5nm for inch-size PCD) to optimize mass transfer kinetics and minimize fouling, crucial for maintaining efficiency in continuous flow systems.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists and electrochemical engineers specializes in optimizing diamond electrode properties (Boron doping level, surface termination, and geometry) for specific Advanced Oxidation Processes (AOPs). We can assist researchers and engineers in:
- Selecting the optimal BDD grade (SCD vs. PCD) based on required current density and desired radical selectivity (e.g., maximizing hydroxyl radical production while minimizing chlorine/chlorate formation).
- Designing electrode arrays for efficient continuous flow systems, ensuring uniform current distribution across large-area plates.
- Providing material consultation for similar Electrochemical Disinfection projects, including toxicity analysis considerations mentioned as a necessary future study in the paper.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Formation and contamination of malicious microorganisms and viruses remain to be major problem of water resources. This is mostly due to the fact that, groundwater, which constitutes a large share of available fresh water content, is prone to contamination from urban and industrial wastes. In this work, electrochemical treatment is considered as a disinfection mechanism. The literature presents several cases of individual of electrochemical disinfection experiments. In this particular work, we aim to focus on the comparative disinfection efficiency of Boron-doped diamond electrodes, Iridium metal-oxide electrodes and Graphite plate electrodes at various electrochemical settings, whilst monitoring formation of toxic bi-products, such as chlorine and other radicals. Experiments of electrochemical water disinfection were carried out on real groundwater samples deliberately contaminated with E. coli culture. During the reaction, microorganisms die due to both direct physical damage and due to the electrochemically generated radicals. Therefore, there is a gentle balance of bacteria elimination versus avoiding excessive radical production in the treated water. Since the biological behaviour of the microorganisms and the chemical properties of the available groundwater cannot be changed, the research parameters boil down to experimenting through various popular electrode types and electrical current settings. In both continuous-flow and recursive systems, the Boron-doped diamond electrodes are observed to provide desirable level of disinfection (as good as Iridium metal-oxide), while yielding lower radicals (as low as those of Graphite-plate), making an ideal compromise for the process.