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pH CHANGE IN ELECTROCHEMICAL OXIDATION OF IMIDACLOPRID PESTICIDE USING BORON-DOPED DIAMOND ELECTRODES

MetadataDetails
Publication Date2017-05-15
JournalTurkish Journal of Engineering
AuthorsBahadır K. Körbahti, Mustafa Ceyhun Erdem
InstitutionsMersin Üniversitesi
Citations4
AnalysisFull AI Review Included

6CCVD Technical Documentation: Advanced Electrochemical Oxidation of Pesticides using Boron-Doped Diamond (BDD) Anodes

Section titled “6CCVD Technical Documentation: Advanced Electrochemical Oxidation of Pesticides using Boron-Doped Diamond (BDD) Anodes”

This research validates the critical role of Boron-Doped Diamond (BDD) electrodes in highly efficient and environmentally compliant wastewater treatment, specifically targeting the recalcitrant pesticide, Imidacloprid (IMD).

  • Superior Mineralization: The BDD electrodes demonstrated high efficacy in the electrochemical oxidation of IMD, leveraging the material’s superior oxygen overpotential to generate powerful hydroxyl radicals ($\cdot$OH).
  • Environmental Compliance Achieved: The process maintained the final wastewater pH within strict local discharge limits (6.0 to 9.0) throughout the optimal operating range, eliminating the need for subsequent chemical neutralization steps.
  • High Current Density Operation: The optimal operational window included high current densities (up to 14.3 mA/cm2), confirming the stability and durability of the BDD anodes under aggressive operating conditions.
  • Process Stability: BDD facilitated stable, continuous operation across a wide temperature range (20°C-60°C) and varying pollutant concentrations (85-186 mg/L).
  • Scalability Potential: The successful application in this electrochemical reactor setup highlights the potential for large-scale industrial deployment of BDD technology for complex organic pollutant destruction.
  • Core Mechanism Confirmation: pH decrease was initially caused by hydroxyl radical production and oxygen evolution, confirming the non-selective, rapid mineralization capabilities unique to BDD anodes.

The following table summarizes the operational parameters and key performance indicators identified in the electrochemical oxidation study using BDD electrodes.

ParameterValueUnitContext
Electrode MaterialBoron-Doped Diamond (BDD)N/AAnode and Cathode
Total Electrode Area260cm2Used in batch reactor setup
Pollutant TestedImidacloprid (IMD) PesticideN/ATarget contaminant
Tested IMD Concentration Range40 - 200mg/LWide operational window
Optimal IMD Concentration85 - 186mg/LMaintains final pH between 6.0 and 9.0
Tested Current Density (J) Range4 - 20mA/cm2High-flux operation
Optimal Current Density (J)7.5 - 14.3mA/cm2Maintains final pH between 6.0 and 9.0
Tested Electrolyte (Na2SO4) Range2 - 10g/LSupporting electrolyte
Optimal Electrolyte Concentration3.3 - 7.7g/LMaintains final pH between 6.0 and 9.0
Tested Reaction Temperature (T) Range20 - 60°CMinimal impact on optimal pH range
Reaction Time (t)120minTime used for optimal parameter determination
Initial pH (High IMD: 200 mg/L)9.9pHpH decrease observed to 5.4
Final pH Compliance Range6 - 9pHMaintained local discharge limits

The study utilized a specific electrochemical process focused on optimizing BDD performance for wastewater remediation.

  1. Material Preparation:

    • Imidacloprid (IMD) concentrate (350 g/L) was diluted using double distilled water to concentrations ranging from 40 to 200 mg/L.
    • Sodium Sulfate (Na2SO4) was used as the supporting electrolyte at concentrations between 2 and 10 g/L.
  2. Electrode Setup:

    • Boron-Doped Diamond (BDD) electrodes (Nb/BDD type, supplied by CONDIAS) were used in a parallel plate configuration.
    • The total active electrode surface area was 260 cm2.
  3. Reactor Operation:

    • A batch electrochemical reactor system was employed, featuring a heating/cooling jacket regulated by a cryostat bath to maintain temperatures between 20°C and 60°C.
    • Power was supplied by a programmable DC source, delivering current densities between 4 and 20 mA/cm2.
  4. Process Monitoring:

    • Samples (10 mL) were withdrawn from the reaction medium every 5 minutes over a 120-minute reaction period.
    • pH measurements were taken using a WTW inoLab BNC720 pH meter.
  5. Data Analysis:

    • pH change ($\Delta$pH) was calculated as the difference between the final pH (pHf at 120 min) and the initial pH (pHi), using the equation: $\Delta$pH = pHf - pHi.

This research confirms BDD as the material of choice for demanding electrochemical wastewater applications requiring robust chemical stability and high radical generation efficiency. 6CCVD is uniquely positioned to supply the advanced BDD materials required to replicate, scale, and industrialize this technology.

The core requirement for this research is a high-conductivity, stable, and chemically inert anode material. 6CCVD provides purpose-built MPCVD diamond to meet these needs:

  • Heavy Boron-Doped Diamond (BDD) Electrodes: To achieve the required $\cdot$OH generation capacity and handle high current densities (up to 20 mA/cm2), a heavily boron-doped film is essential. 6CCVD offers Electro-Chemical Grade BDD films customized for optimized conductivity and stability.
  • Conductive Substrates: The paper utilized Nb/BDD. 6CCVD specializes in depositing BDD films onto various conductive substrates, including Niobium (Nb), Tantalum (Ta), and Silicon (Si), ensuring low contact resistance and maximum longevity under aggressive operating conditions.
  • Thick, Durable Films: Given the long reaction times (120 minutes) and harsh environment, 6CCVD can supply PCD films up to 500 ”m thick, ensuring maximum operational lifespan for industrial installations.

Scaling up the 260 cm2 experimental setup requires specialized material dimensions and integration capabilities that 6CCVD routinely provides:

Requirement6CCVD SolutionAdvantage for Client
Large Electrode AreaCustom PCD/BDD plates and wafers up to 125mm in diameter.Facilitates seamless scaling from laboratory to pilot plant production volumes.
Custom Electrode SizingPrecision laser cutting and shaping services.Allows for complex reactor geometries (e.g., stacked plates or cylindrical configurations) not easily achievable with standard commercial parts.
Interface EngineeringInternal metalization capabilities: Ti, Pt, Au, W, Cu.Essential for creating low-resistance electrical contacts (e.g., Ti/Pt/Au contact layers) needed for efficient, high-current density operation utilized in this study.
Surface FinishPolishing services to achieve Ra < 5 nm for Inch-size PCD.Improves fluid dynamics and prevents the accumulation of scale or fouling agents on the electrode surface, enhancing long-term efficiency.
Shipping LogisticsGlobal shipping via DDU (default) or DDP.Ensures rapid delivery of specialized diamond electrodes worldwide, supporting international research and industrial projects.

6CCVD’s in-house team of PhD material scientists and technical engineers are experts in optimizing diamond materials for advanced electrochemical processes. We offer direct consultation for clients seeking to replicate or extend this research into Pesticide/IMD Electrochemical Oxidation and broader Wastewater Treatment applications. Our support includes material selection guidance to optimize BDD doping concentration, thickness, and substrate choice tailored specifically to your required current density and chemical environment.

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

View Original Abstract

In this study, pH and ΔpH change in the electrochemical oxidation of imidacloprid (IMD) pesticide using boron-doped diamond (BDD) electrodes was investigated in the presence of Na2SO4 electrolyte. The process parameters were operated as imidacloprid concentration (40-200 mg/L), electrolyte concentration (2-10 g/L), current density (4-20 mA/cm2) and reaction temperature (20-60°C). pH and ΔpH values increased with increasing Na2SO4 concentration, current density, and reaction temperature, and decreasing the imidacloprid concentration at 120 min reaction time. The results of this study showed that the pH of the wastewater solution maintained the local pH discharge limits between 6 and 9 after the electrochemical oxidation.