Electrochemical oxidation of amoxicillin in its pharmaceutical formulation at boron doped diamond (BDD) electrode

At a Glance

Metadata	Details
Publication Date	2015-08-26
Journal	Journal of Electrochemical Science and Engineering
Authors	Corneil Quand–Même Gnamba, Foffié Thiery Auguste Appia, Evelyne Marie Hélène Loba, Ibrahima Sanogo, Lassiné Ouattara
Institutions	Université Félix Houphouët-Boigny, University Hospital Medical Center at Treichville
Citations	24
Analysis	Full AI Review Included

Technical Documentation & Analysis: Boron Doped Diamond for Advanced Electrochemical Oxidation

This document analyzes the research paper “Electrochemical oxidation of amoxicillin in its pharmaceutical formulation at boron doped diamond (BDD) electrode” and outlines how 6CCVD’s advanced Microwave Plasma Chemical Vapor Deposition (MPCVD) diamond materials can replicate, scale, and enhance the reported performance for environmental and pharmaceutical applications.

Executive Summary

The research successfully demonstrated the high efficiency of Boron Doped Diamond (BDD) electrodes for the mineralization of amoxicillin, a persistent pharmaceutical pollutant, via electrochemical advanced oxidation processes (EAOPr).

High Efficiency: Achieved up to 92% Chemical Oxygen Demand (COD) removal in 5 hours using BDD as the anode in sulfuric acid electrolyte.
Material Characteristics: The BDD film, grown via Hot-Filament CVD (HF-CVD), was polycrystalline with grain sizes ranging from 0.3 to 0.6 µm, exhibiting quasi-metallic behavior and a wide potential window (2.74 V).
Mechanism Insight: The oxidation process was diffusion-controlled and catalyzed by non-diamond carbon impurities (Csp²) present at the grain boundaries.
Energy Consumption: Specific energy consumption was reported as low as 0.035 kWh COD⁻¹ (in perchloric acid), confirming BDD’s viability for energy-efficient wastewater treatment.
6CCVD Advantage: 6CCVD specializes in high-purity MPCVD BDD, offering superior material quality, larger dimensions (up to 125mm), and lower Csp² impurity content compared to the HF-CVD material used, enabling enhanced current efficiency and industrial scale-up.

Technical Specifications

The following table summarizes the key physical and electrochemical performance data extracted from the research.

Parameter	Value	Unit	Context
BDD Growth Method Used	HF-CVD	N/A	Hot-Filament Chemical Vapor Deposition
Substrate Resistivity	1-3	mΩ cm	Low resistivity p-Si wafer
BDD Film Thickness	~1	µm	Grown film thickness
Film Growth Rate	0.24	µm h⁻¹	CVD process parameter
Polycrystalline Grain Size	0.3-0.6	µm	Determined by SEM
Potential Window (H₂SO₄)	2.74	V	Wide electrochemical stability window
Highest COD Removal	92	%	5 h electrolysis @ 100 mA cm⁻² (H₂SO₄)
Current Density Range Tested	20 to 135	mA cm⁻²	Galvanostatic bulk electrolysis
COD Removal Rate Constant (H₂SO₄)	0.5258	s⁻¹	Pseudo first order reaction
Specific Energy Consumption (HClO₄)	0.035	kWh COD⁻¹	Lowest energy consumption reported
Anodic Peak Separation (ΔE_p)	276	mV	Quasi-reversible behavior (120 mV min⁻¹)

Key Methodologies

The experimental procedure focused on the synthesis and characterization of the BDD electrode, followed by electrochemical testing for amoxicillin degradation.

BDD Synthesis (HF-CVD): BDD thin films (~1 µm) were deposited on low resistivity (1-3 mΩ cm) p-Si wafers (10 cm diameter, 0.5 mm thickness).
Process Gas Mixture: 1% CH₄ in H₂ containing trimethylboron (dopant source).
Physical Characterization:
- Scanning Electron Microscopy (SEM) confirmed polycrystalline structure (0.3-0.6 µm grains).
- Raman Spectroscopy identified Csp³ (diamond, 1332 cm⁻¹) and Csp² (graphitic impurities, 1550 cm⁻¹).
- X-ray Photoelectron Spectroscopy (XPS) confirmed C-C and C-H bonds, and a low O/C ratio (0.209).
Electrochemical Setup: A three-electrode cell was used for voltammetry (working area 1 cm²), utilizing a Platinum wire counter electrode (CE) and a Saturated Calomel Electrode (SCE) reference electrode.
Bulk Electrolysis: Exhaustive electrolysis was performed in a batch reactor (exposed area 16 cm²) under galvanostatic control, varying current densities (20-135 mA cm⁻²) in 0.1 M H₂SO₄ or 0.1 M HClO₄ electrolytes.
Performance Measurement: Chemical Oxygen Demand (COD) removal was monitored over 5 hours to determine mineralization efficiency and specific energy consumption.

6CCVD Solutions & Capabilities

6CCVD’s expertise in MPCVD diamond manufacturing provides materials that directly address the requirements of this research, offering superior purity, scalability, and integration capabilities necessary for industrializing advanced oxidation processes.

Applicable Materials

The research confirms the effectiveness of BDD for pharmaceutical wastewater treatment. 6CCVD recommends the following materials to replicate or significantly advance this work:

Heavy Boron Doped PCD (Polycrystalline Diamond):
- Advantage: 6CCVD’s MPCVD process yields BDD with significantly lower non-diamond carbon (Csp²) impurities compared to the HF-CVD material used in the study. While Csp² catalyzed oxidation in the paper, minimizing these impurities enhances the electrode’s stability and maximizes the production of highly reactive hydroxyl radicals (OH•) from the diamond surface, leading to higher current efficiency and reduced side reactions (like OER) at high current densities.
- Format: Available as plates/wafers up to 125mm in diameter, ideal for scaling up the 16 cm² electrode used in the bulk electrolysis experiment.
- Thickness: Customizable PCD thickness from 0.1 µm up to 500 µm, allowing optimization for mechanical stability and electrical contact.

Customization Potential

The successful transition of this research from lab-scale (16 cm² electrode) to industrial application requires precise material engineering, which 6CCVD provides:

Requirement from Research	6CCVD Customization Capability	Benefit to Customer
Substrate Integration	Custom BDD deposition on various substrates (Si, Nb, W, etc.)	Ensures optimal electrical contact and thermal management for high-power applications.
Electrode Dimensions	Plates/wafers up to 125mm (PCD)	Enables direct scale-up of the electrochemical reactor design beyond the 16 cm² used in the study.
Surface Finish	Polishing capability to Ra < 5 nm (Inch-size PCD)	Reduces surface defects and minimizes Csp² exposure, improving long-term electrode stability and lifetime.
Electrical Contact	Internal metalization capability (Au, Pt, Ti, W, Cu)	Provides robust, low-resistance back contacts essential for high-current galvanostatic operation (up to 135 mA cm⁻²).
Doping Control	Precise control over Boron doping concentration	Allows tuning of the BDD’s quasi-metallic properties to optimize the potential window and electron transfer kinetics for specific pollutants.

Engineering Support

The paper highlights the complex interplay between electrolyte chemistry (H₂SO₄ vs. HClO₄) and the formation of secondary oxidants (persulfate vs. perchlorate/peroxide).

6CCVD’s in-house PhD team can assist with material selection and optimization for similar Electrochemical Advanced Oxidation (EAOPr) projects.
We provide consultation on how specific BDD properties (doping level, surface termination, and Csp² content) influence the generation of key reactive species (OH•, persulfate, etc.) to maximize COD removal efficiency and minimize specific energy consumption.
We offer global shipping (DDU default, DDP available) to ensure rapid delivery of custom BDD electrodes worldwide.

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

View Original Abstract

In this work, voltammetric andelectrolysis experiments have been carried out on a conductive boron dopeddiamond (BDD) electrode in solution containing amoxicillin in itspharmaceutical formulation. The physical characterization of the BDD surface byscanning electron microscopy (SEM) reveals a polycrystalline structure withgrain sizes ranging between 0.3 and 0.6 µm. With Raman spectroscopy, BDDsurface is composed of diamons (Csp3) type carbon (Csp3)and graphitic type carbon (Csp2). The electrochemical characterization of the BDD electrode in sulfuric acid electrolyte showed a wide potential window worthing 2.74 V. The oxidation of Amoxicillin showed an irreversible anodic wave on the voltammogram in the domain of water stability indicating a direct oxidation of amoxicillin at BDD surface. The treatment of Amoxicillin in the synthetic wastewaters under various constant current densities 20, 50, 100, 135 mA cm-2 on BDD showed that Amoxicillin is highly reducedunder 100 mA cm-2 reaching 92% of the Chemical Oxygen Demand (COD)removal after 5 h of electrolysis. Investigation performed in perchloric acidas supporting electrolyte led to 87% of COD removal after 5 h of electrolysis.Mineralization of amoxicillin occurs on BDD and the chemical oxygen demandremoval was higher in sulfuric acid than in perchloric acid owing to theinvolvement of the in-situ formed persulfate and perchlorate to the degradation process mainly in the bulkof the solution. The instantaneous current efficiency (ICE) presents anexponential decay indicating that the process was limited by diffusion. Thespecific energy consumed after 5h of the amoxicillin electrolysis was 0.096 kWh COD-1and 0.035 kWh COD-1 in sulfuric acid and in perchloric acidrespectively.

Tech Support

Original Source

DOI: https://doi.org/10.5599/jese.186