Electrochemical Oxidation of Anastrozole over a BDD Electrode - Role of Operating Parameters and Water Matrix

At a Glance

Metadata	Details
Publication Date	2022-11-14
Journal	Processes
Authors	Rebecca Dhawle, Zacharias Frontistis, Dionissios Mantzavinos
Institutions	University of Nicosia, University of Patras
Citations	10
Analysis	Full AI Review Included

Technical Documentation & Analysis: Electrochemical Oxidation of Anastrozole using BDD Electrodes

This document analyzes the research concerning the electrochemical oxidation (EO) of Anastrozole (ANZ) using Boron-Doped Diamond (BDD) electrodes. It highlights the technical requirements of the study and maps them directly to the advanced MPCVD diamond capabilities offered by 6CCVD, positioning our materials as the superior choice for replicating and scaling this Advanced Oxidation Process (AOP).

Executive Summary

The following points summarize the core technical achievements and material requirements of the study:

Application Validation: Confirmed the efficacy of Electrochemical Oxidation (EO) using BDD anodes for the degradation of Anastrozole (ANZ), an environmentally persistent pharmaceutical micropollutant.
High Removal Efficiency: Achieved 97.5% removal of 1 mg L^-1 ANZ within 90 minutes at a current density of 12.5 mA cm^-2, demonstrating high performance in water treatment.
Kinetic Dependence: Degradation follows pseudo-first-order kinetics, with the apparent rate constant (k_app) increasing proportionally with current density (doubling j from 6.25 to 12.5 mA cm^-2 doubled k_app from 0.022 to 0.0422 min^-1).
Radical Mechanism: The primary mechanism involves the electro-generation of highly oxidative hydroxyl (·OH) radicals on the BDD surface, confirmed by tert-butanol scavenging experiments.
Material Requirement: The process relies entirely on the wide potential window and high stability of the BDD electrode (B/C = 1000 ppm) to efficiently generate reactive oxygen species (ROS).
Process Robustness: EO proved robust across a wide pH range (3-10), a significant advantage over competing AOPs like solar photo-Fenton, which require strict pH control (pH 5).
Economic Viability: Preliminary cost analysis yielded Electric Energy per Order (EEO) values between 23.1 and 25 kWh m^-3/order, confirming the potential for industrial scale-up, especially with decreasing renewable energy costs.

Technical Specifications

The following hard data points were extracted from the experimental results:

Parameter	Value	Unit	Context
Anode Material Specification	B/C = 1000	ppm	Boron-Doped Diamond (BDD)
Active Electrode Area	16	cm²	Used for both BDD anode and stainless steel cathode
Optimal Current Density (j)	12.5	mA cm^-2	Achieved 97.5% ANZ removal
Standard Current Density (j)	6.25	mA cm^-2	Achieved 82.4% ANZ removal
Optimal k_app	0.0422	min^-1	At j = 12.5 mA cm^-2
k_app at Acidic pH	0.0394	min^-1	At j = 6.25 mA cm^-2, pH 3
Hydroxyl Radical Concentration	0.77 x 10^-13	M	Steady state, calculated at j = 12.5 mA cm^-2
ANZ Diffusion Coefficient	3.1 x 10^-7	cm²/s	Estimated via Chronoamperometry
Electrolyte Concentration	0.1	M	Typically Na₂SO₄
EEO (Energy Consumption) Range	23.1 - 25	kWh m^-3/order	Dependent on current density
Estimated Process Cost	3.3 - 3.6	€ m^-3/order	Based on EU electricity prices

Key Methodologies

The electrochemical oxidation experiments were conducted under the following controlled parameters:

Reactor Configuration: Batch mode operation in a 200 mL rectangular plexiglass reactor, open to the air, maintained at room temperature.
Electrode Materials: Boron-doped diamond (BDD) served as the anode, and a stainless-steel plate served as the cathode. Both electrodes had an active surface area of 16 cm².
Electrical Operation: Experiments were performed under galvanostatic conditions, with current supplied by a programmable power unit.
Electrolyte Composition: 0.1 M Na₂SO₄ was used as the standard supporting electrolyte. Comparative tests utilized 0.1 M NaCl and various concentrations of chloride, bicarbonate, and humic acid.
Current Density Control: Two primary current densities were tested: 6.25 mA cm^-2 and 12.5 mA cm^-2.
pH Management: Initial pH was adjusted (unbuffered) using 1 M NaOH or 1 M H₂SO₄ to test the range of pH 3 to pH 10.
Mass Transfer: Continuous magnetic stirring was employed to minimize mass transfer limitations.
Analytical Quenching: Samples were collected at regular intervals, quenched immediately with methanol (0.3 mL), filtered, and analyzed using High-Pressure Liquid Chromatography (HPLC).

6CCVD Solutions & Capabilities

The successful replication and industrial scaling of this electrochemical AOP depend critically on the quality, consistency, and customizability of the BDD electrode material. 6CCVD is uniquely positioned to supply the high-performance diamond required for this application.

Applicable Materials

The research explicitly requires a high-quality, non-active anode capable of efficient hydroxyl radical generation.

Material Recommendation: Heavy Boron-Doped PCD (Polycrystalline Diamond) or SCD (Single Crystal Diamond) Wafers.
- PCD BDD: Ideal for large-area industrial electrochemical cells due to its scalability and cost-effectiveness. 6CCVD can precisely match or exceed the 1000 ppm B/C ratio used in the study, ensuring optimal conductivity and radical generation efficiency.
- SCD BDD: Recommended for fundamental research or high-precision micro-reactor applications where ultra-low defect density and superior uniformity are paramount for kinetic studies.

Customization Potential for Scale-Up

The study utilized small, 16 cm² electrodes. 6CCVD’s capabilities directly address the need to scale this technology from the lab bench to pilot and industrial systems.

Research Requirement	6CCVD Customization Capability	Value Proposition
Electrode Size (16 cm²)	Custom Dimensions up to 125mm	We supply large-area PCD plates (up to 125mm diameter) or custom laser-cut geometries, enabling seamless scale-up of the reactor design.
Electrode Thickness	SCD/PCD Thickness: 0.1µm - 500µm	We provide precise thickness control, optimizing material usage and minimizing ohmic losses for improved EEO metrics in industrial cells.
Surface Quality	Polishing: Ra < 5nm (PCD), Ra < 1nm (SCD)	Superior polishing ensures a highly uniform, stable surface morphology, crucial for consistent and long-term ·OH radical electro-generation, extending electrode lifespan.
Electrical Contact	Custom Metalization Services	We offer in-house deposition of robust contact layers (Au, Pt, Pd, Ti, W, Cu) to ensure low-resistance electrical connections, vital for maintaining high current densities (12.5 mA cm^-2) efficiently.

Engineering Support

The research highlighted the complex influence of the water matrix (chloride, bicarbonate, organic matter) on ANZ degradation kinetics. Optimizing BDD performance for specific wastewater streams requires expert material knowledge.

Application Expertise: 6CCVD’s in-house PhD team specializes in MPCVD diamond growth and electrochemical applications. We provide consultation on optimizing the boron doping level (B/C ratio) and surface termination to maximize the selectivity and yield of hydroxyl radicals (·OH) over competing oxidants (like ClO^- or SO₄^-·) for similar Pharmaceutical Wastewater Treatment projects.
Global Logistics: We offer reliable global shipping (DDU default, DDP available) to ensure researchers and engineers worldwide receive their custom BDD materials promptly and securely.

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

View Original Abstract

The electrochemical oxidation (EO) of the breast-cancer drug anastrozole (ANZ) is studied in this work. The role of various operating parameters, such as current density (6.25 and 12.5 mA cm−2), pH (3-10), ANZ concentration (0.5-2 mg L−1), nature of supporting electrolytes, water composition, and water matrix, have been evaluated. ANZ removal of 82.4% was achieved at 1 mg L−1 initial concentration after 90 min of reaction at 6.25 mA cm−2 and 0.1 M Na2SO4. The degradation follows pseudo-first-order kinetics with the apparent rate constant, kapp, equal to 0.022 min−1. The kapp increases with increasing current density and decreasing solution pH. The addition of chloride in the range 0-250 mg L−1 positively affects the removal of ANZ. However, chloride concentrations above 250 mg L−1 have a detrimental effect. The presence of bicarbonate or organic matter has a slightly negative but not significant effect on the process. The EO of ANZ is compared to its degradation by solar photo-Fenton, and a preliminary economic analysis is also performed.

Tech Support

Original Source

DOI: https://doi.org/10.3390/pr10112391

References

2018 - Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries [Crossref]
2022 - Formulation, optimization, and in vitro evaluation of anastrozole-loaded nanostructured lipid carriers for improved anticancer activity [Crossref]
2003 - Pharmacokinetics of third-generation aromatase inhibitors [Crossref]
2004 - Anastrozole (ArimidexR) [Crossref]
2017 - European demonstration program on the effect-based and chemical identification and monitoring of organic pollutants in European surface waters [Crossref]
2010 - Analysis of hormone antagonists in clinical and municipal wastewater by isotopic dilution liquid chromatography tandem mass spectrometry [Crossref]