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6CCVD Research

Influence of Supporting Electrolytes on RO 16 Dye Electrochemical Oxidation Using Boron Doped Diamond Electrodes

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2017-03-13
JournalMaterials Research
AuthorsFernanda L. Migliorini, Andréa Boldarini Couto, Suellen Aparecida Alves, Marcos R.V. Lanza, N.G. Ferreira
InstitutionsUniversidade de SĂŁo Paulo, Universidade Federal de SĂŁo Carlos
Citations8
AnalysisFull AI Review Included

Technical Analysis & Documentation for Electrochemical Oxidation using BDD

Section titled “Technical Analysis & Documentation for Electrochemical Oxidation using BDD”

Executive Summary

Section titled “Executive Summary”

This research validates the critical role of Boron-Doped Diamond (BDD) electrodes, specifically BDD grown on Titanium (BDD/Ti), for advanced oxidation processes (AOPs) targeting textile dye wastewater (Reactive Orange 16). The key findings and value proposition for high-performance electrochemistry are:

  • Electrode Efficacy: BDD/Ti electrodes demonstrated significant effectiveness in removing the intense orange color (azo-dye degradation) and mineralizing organic load (TOC removal) from textile wastewater.
  • pH Optimization: Electrochemical oxidation performance is significantly enhanced in basic medium (pH 10, using K2SO4), achieving 96% color removal compared to 65% in neutral pH. This is attributed to the increased generation of hydroxyl ions (OH-) and dye deprotonation.
  • High Current Density Performance: Degradation efficiency (measured by the pseudo first-order kinetic constant, kapp) increased linearly with higher current density, proving the stability of BDD electrodes under aggressive conditions.
  • Mineralization Rate: A 30% Total Organic Carbon (TOC) removal efficiency was achieved at the highest current density tested (100 mA cm-2).
  • Material Quality: The synthesized BDD film exhibited high crystallinity and adherence, successfully mitigating common issues related to diamond growth on Ti substrates (cracks and delamination).
  • Productivity: The method produces more polar, potentially biodegradable intermediates, making it highly valuable for industrial wastewater pre-treatment stages.

Technical Specifications

Section titled “Technical Specifications”

The following table extracts the key performance and fabrication parameters detailed in the study:

ParameterValueUnitContext
BDD Doping Level (B/C)15,000ppmAchieved through B2O3/CH3OH doping source.
BDD Growth Temperature650°CHFCVD process parameter.
BDD Growth Pressure40TorrChamber pressure during deposition.
Electrode SubstrateTitanium (Ti)N/ASubstrate material for BDD film growth.
Working Electrode Area~4.15cm2Geometric area used in the electrochemical cell.
Optimal Current Density100mA cm-2Highest kinetic rate observed; 30% TOC removal.
Optimal Electrolyte/pHK2SO4 (0.1 mol L-1)N/AAchieved 96% color decay efficiency.
TOC Removal Efficiency30%Measured at 100 mA cm-2 (highest density).
Azo-Dye Max Absorption (UV-Vis)388 / 500nmUsed for concentration and color decay measurements.
Raman Shift (Diamond Peak)1332cm-1Confirmed diamond first-order phonon vibration.
Electrolysis Temperature25°CConstant temperature for all degradation experiments.

Key Methodologies

Section titled “Key Methodologies”

The BDD/Ti electrode preparation and subsequent dye degradation experiments followed precise, controlled procedures.

I. BDD Electrode Fabrication (HFCVD)

Section titled “I. BDD Electrode Fabrication (HFCVD)”
  1. Substrate Preparation: Titanium (Ti) substrates (2.5 x 2.5 x 0.5 mm) were mechanically incised using air abrasion with glass beads to increase surface area, roughness, and mechanical anchoring, improving film adhesion and reducing stress.
  2. Gas Mixture: A standard gas mixture of 99% H2 and 1% CH4 was used.
  3. Doping Injection: Boron doping was introduced using an additional H2 gas flux (40 sccm) passing through a bubbler containing B2O3 dissolved in CH3OH, achieving a B/C ratio of 15,000 ppm.
  4. CVD Conditions: The process was run for 16 hours at a fixed temperature of 650 °C and a chamber pressure of 40 Torr.
  5. Characterization: Film quality and composition were confirmed via SEM (morphology/adherence), Micro-Raman Spectroscopy (diamond peak 1332 cm-1, BDD disorder 1200 cm-1), and GIXRD (identification of diamond, TiC, and TiH phases).

II. Electrochemical Degradation (Galvanostatic Mode)

Section titled “II. Electrochemical Degradation (Galvanostatic Mode)”
  1. Cell Setup: Experiments were conducted in a polypropylene single cell (0.45 L capacity) using the BDD/Ti as the working anode and a 2 cm diameter platinum screen as the counter cathode. An Ag/AgCl reference electrode was used.
  2. Initial Conditions: RO16 azo-dye solution (150 mg L-1) was treated at a constant temperature of 25 °C with continuous stirring.
  3. Electrolyte Testing (Step 1): Initial tests were performed at a fixed current density of 50 mA cm-2 using four supporting electrolytes to determine the optimal chemical environment: H2SO4 (acid), HClO4 (acid), K2SO4 (pH 6.5, neutral), and K2SO4 (pH 10, basic).
  4. Current Density Optimization (Step 2): The optimal electrolyte (K2SO4, pH 10) was used to test four current densities: 25, 50, 75, and 100 mA cm-2.
  5. Analysis: Degradation was monitored using UV-Vis spectroscopy (color removal), High-Performance Liquid Chromatography (HPLC) (intermediate formation), and Total Organic Carbon (TOC) analysis (mineralization efficiency).

6CCVD Solutions & Capabilities

Section titled “6CCVD Solutions & Capabilities”

6CCVD provides the specialized CVD diamond materials and customization services necessary to replicate, optimize, and scale this high-efficiency electrochemical wastewater treatment process.

Applicable Materials

Section titled “Applicable Materials”

To achieve or exceed the performance reported in this research, high-quality, heavily doped diamond is essential. 6CCVD’s specialized MPCVD (Microwave Plasma CVD) process offers crucial advantages over the HFCVD method used in the paper, yielding superior film uniformity, purity, and electronic characteristics required for industrial-scale AOP electrodes.

Research Requirement6CCVD Recommended SolutionKey Feature for AOP
Boron-Doped FilmHeavy Boron Doped Polycrystalline Diamond (PCD)High concentration of active sites (M), wide potential window, and high corrosion resistance essential for aggressive electrolytic media (especially alkaline conditions).
High Doping Level (15,000 ppm B/C)Custom BDD Doping Specification6CCVD guarantees precise B/C ratio control tailored to maximize conductivity and hydroxyl radical generation (‱OH).
Inert, Non-Active AnodeHigh Purity BDD WafersEnsures the formation of high-oxidizing potential radicals (‱OH) rather than undesirable intermediate byproducts.

Customization Potential & Manufacturing Scale-Up

Section titled “Customization Potential & Manufacturing Scale-Up”

The research utilized small, laboratory-scale electrodes (~4.15 cm2). Scaling up AOP systems for industrial textile waste treatment requires large-area, high-adherence BDD plates.

  • Large Area Electrodes: 6CCVD offers PCD plates/wafers up to 125mm in diameter. This capability is vital for moving electrochemical dye degradation from R&D to high-throughput, industrial reactors.
  • Custom Substrates: While the paper used Ti, 6CCVD routinely provides BDD growth on Silicon (Si), Niobium (Nb), and custom metallic substrates (including Ti) with exceptional film adhesion, addressing the delamination challenges noted in the paper.
  • Thickness Control: 6CCVD supports both thin-film BDD requirements (down to 0.1 ”m) and thicker, mechanically robust plates (up to 500 ”m BDD, and substrates up to 10 mm) for long-lifetime industrial anodes.
  • Metalization Services: Although not explicitly detailed for the BDD/Ti anode in the paper, industrial integration often requires robust electrical contacts. 6CCVD offers custom metalization layers (Au, Pt, Ti, W, Cu) to ensure stable, low-resistance connection for high-current galvanostatic applications (up to 100 mA cm-2).
  • Finishing & Polishing: While electrochemical anodes are typically left unpolished, 6CCVD provides precision polishing (Ra < 5nm for PCD) should researchers require ultra-smooth surfaces for follow-up analytical work or specific cell designs.

Engineering Support & Global Logistics

Section titled “Engineering Support & Global Logistics”

6CCVD’s in-house PhD team specializes in CVD diamond characteristics and can assist engineers in selecting the optimal BDD material specifications (doping level, thickness, and substrate selection) required to enhance Electrochemical Advanced Oxidation Processes (EAOP), focusing on efficient hydroxyl radical generation and mineralization.

6CCVD provides reliable Global Shipping, with DDU as the default option and DDP available upon request, ensuring timely delivery of critical diamond components worldwide.

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

View Original Abstract

The influence of different supporting electrolytes as well as of different current densities on RO16 dye electrochemical oxidation using BDD electrodes has been systematically studied. The RO16 azo-dye electrooxidation experiments were performed at different current densities and three different supporting electrolytes: H2SO4 0.1 mol L-1, HClO4 0.1 mol L-1 and K2SO4 0.1 mol L-1. The results showed that a higher degradation for reactive azo dye RO16 was observed for the K2SO4 (pH=10) supporting electrolyte for a current density of 100 mA cm-2. This behavior can be associated with the deprotonation effect of the dye molecule, which can facilitate breakdown of the molecule, specifically the azo bond making color removal more efficient. In addition, in this pH there is a greater amount of hydroxyl ion (OH-) available increasing the hydroxyl radical formation.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2000 - Corantes tĂȘxteis [Crossref]
  2. 2005 - Decolourization of Industrial Effluents - Available Methods and Emerging Technologies - a Review [Crossref]
  3. 2004 - Aromatic amines from azo dye reduction: status review with emphasis on direct UV spectrophotometric detection in textile industry wastewaters [Crossref]
  4. 2003 - Pathways of solar light-induced photocatalytic degradation of azo dyes in aqueous TiO2 suspensions [Crossref]
  5. 2002 - Photodegradation of an azo dye of the textile industry [Crossref]
  6. 2009 - Electrochemical degradation of phenol using electrodes of Ti/RuO2-Pt and Ti/IrO2-Pt [Crossref]
  7. 2008 - Photo-electrochemical degradation of some chlorinated organic compounds on n-TiO2 electrode [Crossref]
  8. 2005 - Electrochemical activity, stability and degradation characteristics of IrO2-based electrodes in aqueous solutions containing C1 compounds [Crossref]
  9. 2004 - Degradation of chlorophenols by means of advanced oxidation processes: a general review [Crossref]
  10. 2005 - Degradation of 4,6-dinitro-o-cresol from water by anodic oxidation with a boron-doped diamond electrode [Crossref]

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