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Inhibition of staphylococci and S. aureus in wastewater by ferrates and electrochemical methods

MetadataDetails
Publication Date2020-10-01
JournalActa Chimica Slovaca
AuthorsAlĆŸbeta MedveďovĂĄ, Stanislava KecskĂ©sovĂĄ, Anna KrivjanskĂĄ, MariĂĄn Vojs, MariĂĄn Marton
InstitutionsPalackĂœ University Olomouc, Regional Centre of Advanced Technologies and Materials
AnalysisFull AI Review Included

Technical Documentation & Analysis: MPCVD Diamond for Advanced Electrochemical Oxidation

Section titled “Technical Documentation & Analysis: MPCVD Diamond for Advanced Electrochemical Oxidation”

This research validates the superior performance of Boron-Doped Diamond Electrodes (BDDE) in eliminating antibiotic-resistant pathogens from municipal wastewater, a critical application for 6CCVD’s materials portfolio.

  • Core Achievement: Complete (100%) inhibition of coagulase-positive staphylococci and S. aureus in wastewater effluent using Advanced Electrochemical Oxidation (AEO).
  • Optimal Configuration: The BDD electrode connected in an anodic configuration proved most effective, achieving 100% disinfection efficiency in 40 minutes.
  • Material Specification: The high efficiency was achieved using heavily doped BDD films (500 nm thick) synthesized via HFCVD with a high Boron-to-Carbon (B/C) ratio of 10,000 ppm.
  • Mechanism: Anodic connection generates highly potent Hydroxide Radicals (HO˚), which are the strongest oxidizing agents, leading to rapid microbial elimination.
  • Application Relevance: This study confirms BDD as the material of choice for tertiary wastewater treatment, specifically targeting multidrug-resistant microorganisms and micropollutants.
  • 6CCVD Value Proposition: 6CCVD specializes in producing high-quality, heavily doped BDD wafers and plates, offering the custom dimensions and doping levels required to scale this technology for industrial water treatment systems.

The following parameters detail the BDD material synthesis and electrochemical performance achieved in the study:

ParameterValueUnitContext
Material TypeBoron-Doped Diamond (BDD)N/AThin film grown on Si substrate
Film Thickness500nmGrown for 120 min via HFCVD
Boron Doping (B/C Ratio)10,000ppmAchieved using Trimethylboron (TMB)
Substrate MaterialSilicon (Si)N/ADimensions: 10 x 9 x 10 mm
Substrate Temperature650°CDuring HFCVD deposition
Filament Temperature2100°CTungsten filaments (0.7 mm diameter)
Applied Voltage (DC)30VUsed for electrochemical oxidation
Anode Surface Area16cm2Total area of 10 BDD/Si substrates
Disinfection Time (100% Effluent)40minAchieved using BDD Anode connection
Inhibition Efficiency100%Against S. aureus and staphylococci in effluent
Energy Consumption (E)3.96kWh/m3Required for complete disinfection of 1 m3 effluent

The BDD thin films were synthesized using Hot Filament Chemical Vapor Deposition (HFCVD), a technique closely related to 6CCVD’s core MPCVD capabilities, ensuring high material quality and precise doping control.

  1. Substrate Preparation: Silicon (Si) substrates (10 x 9 x 10 mm) were used for BDD film overgrowth.
  2. HFCVD Synthesis: Films were grown for 120 minutes to achieve a nominal thickness of 500 nm.
  3. Gas Mixture: A 2% methane (CH4) in hydrogen (H2) gas mixture was employed.
  4. Doping Control: Trimethylboron (TMB) was added to achieve a high Boron-to-Carbon (B/C) ratio of 10,000 ppm, critical for metallic conductivity.
  5. Process Conditions: Deposition occurred at 3 kPa pressure and a substrate temperature of 650 °C, utilizing tungsten filaments heated to 2100 °C for gas activation.
  6. Electrode Setup: Ten BDD/Si substrates were configured as the anode (16 cm2 total area) opposite a graphite rod cathode (10 mm diameter), separated by 1 cm.
  7. Disinfection Test: Wastewater samples (300 ml) were treated at a constant potential difference (30 V DC) for up to 60 minutes, with samples taken periodically to monitor microbial inhibition.

This research demonstrates the commercial viability of BDD electrodes for advanced water purification. 6CCVD is uniquely positioned to supply the high-specification diamond materials required to scale this technology from the lab to industrial Wastewater Treatment Plants (WWTPs).

To replicate or extend this high-efficiency electrochemical disinfection research, 6CCVD recommends the following materials:

  • Heavy Boron-Doped Diamond (BDD) Wafers: Essential for achieving the metallic conductivity and high overpotential necessary for efficient HO˚ radical generation.
    • Doping Match: We routinely achieve and exceed the 10,000 ppm B/C ratio used in this study, ensuring optimal electrochemical performance.
    • Substrate Flexibility: While Si was used here, 6CCVD can deposit BDD films on various substrates (e.g., Nb, Ta, or large-area PCD) for enhanced mechanical stability and scalability.
  • Polycrystalline Diamond (PCD) Substrates: For large-scale industrial reactors, BDD films can be grown on robust, inch-size PCD plates, offering superior chemical inertness and thermal management compared to silicon.

The study utilized small, custom-cut silicon substrates (10 x 9 x 10 mm). 6CCVD’s manufacturing capabilities are designed to meet the exact dimensional and integration requirements of industrial AEO systems.

Research Requirement6CCVD Customization CapabilitySales Advantage
Small Substrate SizeCustom laser cutting and shaping services.Allows for precise integration into existing reactor designs and prototyping.
Electrode Area (16 cm2)Plates/wafers up to 125 mm diameter (PCD) or large-area SCD.Enables immediate scale-up to industrial reactor sizes, significantly increasing throughput.
Film Thickness (500 nm)SCD and PCD thickness control from 0.1 ”m up to 500 ”m.Guaranteed thickness uniformity across large areas, crucial for consistent electrode lifetime.
Electrical ContactInternal metalization services (Au, Pt, Pd, Ti, W, Cu).We provide robust, low-resistance metal contacts necessary for high-current anodic operation (30 V DC).
Surface FinishPolishing capability (Ra < 5 nm for inch-size PCD).While not primary for AEO, high-quality polishing ensures minimal surface defects and maximizes active area stability.

The successful implementation of BDD technology relies on optimizing the material properties (doping, thickness, substrate choice) for specific wastewater matrices.

  • Expert Consultation: 6CCVD’s in-house PhD team specializes in diamond material science and electrochemical applications. We offer consultation on material selection, doping profile optimization, and electrode design for Advanced Electrochemical Oxidation (AEO) projects.
  • Global Logistics: We provide reliable global shipping (DDU default, DDP available) to ensure timely delivery of custom BDD electrodes for pilot and full-scale WWTP projects worldwide.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Abstract Increasing concentration of antibiotics in environment and their subinhibitory concentrations in wastewater may result in increased antibiotic resistance of present bacteria. Therefore, this study was aimed to analyze the efficiency of coagulase-positive staphylococci and Staphylococcus aureus inhibition in wastewater by electrochemical methods and addition of ferrates. Advanced electrochemical oxidation by boron doped diamond electrodes in anode; cathode and anode-cathode connection were used for wastewater disinfection. Results showed that the most effective connection was the anodic one, as complete inhibition of coagulase-positive staphylococci as well as of S. aureus was observed after 40 min. Energy consumption was 3.69 kWh/m 3 for effluent wastewater disinfection. The second studied method of wastewater disinfection was the application of powdered ferrates. Addition of 100 mg of ferrates resulted in the inhibition of 84—96 % of coagulase-positive staphylococci and 97—99 % of S. aureus in influent water, while the inhibition of coagulase-positive staphylococci and S. aureus was 61—83 % and 83—86 %, respectively, in effluent wastewater.