Electrochemical Degradation of Venlafaxine on Platinum Electrodes - Identification of Transformation Products by LC-MS/MS and In Silico Ecotoxicity Assessment

At a Glance

Metadata	Details
Publication Date	2025-04-23
Journal	Molecules
Authors	Angelica Rebecca Zizzamia, Veronica Pasquariello, Filomena Lelario, Carmen Tesoro, Rosanna Ciriello
Institutions	University of Basilicata
Citations	1
Analysis	Full AI Review Included

Technical Documentation & Sales Analysis: Electrochemical Degradation of Venlafaxine

This document analyzes the research paper “Electrochemical Degradation of Venlafaxine on Platinum Electrodes” to provide technical specifications and highlight how 6CCVD’s advanced MPCVD diamond materials and services can support and extend this research, particularly in addressing the limitations of Boron-Doped Diamond (BDD) electrodes cited in the study.

Executive Summary

This research validates the use of Platinum (Pt) electrodes as a stable, reproducible alternative to Boron-Doped Diamond (BDD) for the electrochemical degradation of the emerging contaminant Venlafaxine (VFX).

Core Achievement: Achieved 94% VFX degradation efficiency (25 ppm solution) in 7 hours using a Pt anode under optimized galvanostatic conditions (25 mA/cm², pH 9).
Mechanism: Degradation relies on indirect oxidation mediated by electrochemically generated hydroxyl (•OH) and sulfate (SO₄^•-) radicals, operating effectively in a chloride-free electrolyte (0.1 M Na₂SO₄).
Sustainability: The method is environmentally sustainable, confirmed by in silico ECOSAR analysis, which showed that 9 out of 10 identified transformation products were less toxic than the parent compound.
BDD Challenge Highlighted: The paper explicitly notes critical limitations of BDD electrodes, including susceptibility to delamination, difficulties in scaling up, and lack of standardized cleaning protocols due to morphological variability.
6CCVD Value Proposition: 6CCVD specializes in custom, high-stability MPCVD BDD, directly addressing the delamination and scaling challenges cited, offering superior electrochemical performance for next-generation EAOP systems.

Technical Specifications

The following table summarizes the key operational parameters and performance metrics achieved using the optimized Platinum electrode system.

Parameter	Value	Unit	Context
Anode Material Tested	Platinum (Pt) Foil	N/A	Selected for stability and reproducibility
Anode Dimensions	0.005 x 1 x 1	Inch (0.127 x 25 x 25 mm)	Exposed surface area: 8 cm²
Cathode Material	Graphite Plate	N/A	Counter electrode
Supporting Electrolyte	0.1 M Na₂SO₄	N/A	Chloride-free, active electrolyte
Optimized pH	9	N/A	Favors •OH radical formation
Current Density (Optimized)	25	mA/cm²	Galvanostatic operation
Initial VFX Concentration	25	mg/L (ppm)	Used for transformation product identification
Degradation Efficiency	94	%	Achieved after 7 hours (420 min)
Kinetic Model	First-Order	N/A	Rate constant: 0.0084 min^-1
Energy Consumption	98	kWh/m³	For 94% degradation of 25 ppm VFX
Parent Compound (VFX) LC₅₀	11.1	mg/L	Ecotoxicity (Daphnia magna)
Most Toxic Intermediate (V276a) LC₅₀	7.8	mg/L	Ecotoxicity (Daphnia magna)

Key Methodologies

The electrochemical degradation was conducted using a galvanostatic setup optimized for indirect oxidation under environmentally relevant conditions (near-neutral pH, chloride-free).

Electrode Configuration: A two-electrode cell was used, employing a Platinum foil anode and a Graphite plate cathode, separated by 2 cm in a 100 mL reactor volume.
Pt Anode Cleaning Protocol: The Pt surface reproducibility was ensured via a multi-step cleaning process: mechanical polishing (0.05 µm alumina), sonication in hot 70% nitric acid, and electrochemical cycling in 0.5 M sulfuric acid (potential range: -0.225 V to +1.25 V vs. SCE).
Electrolyte and pH Optimization: A 0.1 M Na₂SO₄ solution was selected as the supporting electrolyte to generate sulfate and hydroxyl radicals without forming hazardous chlorinated by-products. pH 9 was chosen to maximize •OH radical formation.
Current Density Selection: Degradation efficiency was tested at 5, 10, and 25 mA/cm². The highest current density (25 mA/cm²) yielded the maximum degradation rate (45.5% in 60 min).
Product Identification: Transformation products (TPs) were identified using high-resolution LC-ESI-Orbitrap-MS and LC-ESI-LIT-MSⁿ, enabling the structural elucidation of 10 main by-products, including three mono-hydroxylated isomers (V294a, V294b, V294c).
Toxicity Assessment: The environmental impact was evaluated in silico using the ECOSAR (Ecological Structure Activity Relationships, V2.2) predictive model to calculate LC₅₀ values for Daphnia magna.

6CCVD Solutions & Capabilities

The research confirms the viability of EAOPs for pharmaceutical degradation but highlights critical material science limitations associated with conventional BDD electrodes (delamination, scaling). 6CCVD provides advanced MPCVD diamond solutions and customization services that directly overcome these challenges, enabling researchers to leverage the superior performance of diamond materials reliably.

Applicable Materials for EAOP Research

Research Requirement	6CCVD Material Recommendation	Technical Rationale & Advantage
High Oxygen Overpotential Anodes (Alternative to Pt)	Heavy Boron-Doped Polycrystalline Diamond (BDD-PCD)	BDD offers the widest potential window and highest oxygen overpotential, maximizing indirect oxidation efficiency via radical generation (•OH, SO₄^•-). Our MPCVD process ensures high doping uniformity and stability.
Addressing BDD Delamination	BDD on Thermally Matched Substrates (Ta, Nb, W)	We mitigate the structural defects and electrolyte penetration cited in the paper by engineering BDD films on substrates with optimized thermal expansion coefficients, ensuring long-term operational stability and service life.
Fundamental Electrochemical Studies	Single Crystal Diamond (SCD) Plates	For high-precision mechanistic studies (like the CV analysis performed), SCD offers unparalleled purity and crystalline perfection, minimizing background current and maximizing reproducibility.
Platinum Integration	Custom Metalization (Pt, Ti/Pt/Au)	While the study used Pt foil, 6CCVD can deposit high-purity Pt films onto robust, inert substrates (including diamond or ceramic) via our internal metalization capability, offering the stability of Pt with enhanced mechanical support.

Customization Potential for EAOP System Development

6CCVD’s advanced fabrication capabilities are perfectly suited to replicate, optimize, and scale the electrochemical systems described in this research:

Custom Dimensions and Scaling: The paper used 8 cm² anodes. 6CCVD can supply PCD plates/wafers up to 125 mm in diameter, facilitating the necessary scale-up from laboratory experiments to pilot-scale reactors, addressing a key limitation of BDD cited in the literature.
Thickness Control: We offer precise control over diamond film thickness, ranging from 0.1 µm to 500 µm for both SCD and PCD, allowing researchers to optimize material usage and electrochemical properties.
Surface Engineering: We provide ultra-low roughness polishing (Ra < 5 nm for inch-size PCD), which is critical for ensuring the high surface reproducibility and minimizing fouling required for long-duration EAOP experiments, mirroring the stability achieved by the Pt electrode in this study.
Integrated Electrodes: We offer multi-layer metalization (e.g., Ti/Pt/Au, Ti/W/Cu) for creating robust electrical contacts and integrating active electrode materials onto custom substrates, essential for complex electrochemical cell designs.

Engineering Support

6CCVD’s in-house team of PhD material scientists and electrochemists can assist researchers and engineers in selecting the optimal diamond material (SCD, PCD, or BDD) and substrate configuration required for Advanced Electrochemical Oxidation Processes (EAOPs) targeting emerging contaminants like Venlafaxine. We provide consultation on doping levels, film morphology, and substrate compatibility to ensure maximum electrode stability and efficiency.

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

View Original Abstract

Antidepressants are emerging contaminants that have raised global concern due to their abuse. Venlafaxine (VFX), a serotonin and norepinephrine reuptake inhibitor, can cause adverse and potentially toxic effects on aquatic organisms. Electrochemical advanced oxidation processes (EAOPs) are gaining attention as promising degradation techniques for a variety of drugs. EAOP methods proposed for VFX degradation mainly utilize boron-doped diamond (BDD) electrodes, characterized by low background current and high oxygen overpotential. However, challenges arise, including delamination from the substrate, difficulties in scaling up, and limited service life. In this study, platinum was employed as an anode for the galvanostatic degradation of VFX, due to its stability and well-established surface cleaning procedure, which ensured high reproducibility. A 0.1 M Na2SO4 solution at pH 9 was used as the supporting electrolyte, and a current density of 25 mA/cm2 was applied. After 7 h, a degradation efficiency of 94% was achieved for a 25 ppm VFX solution. The hydroxyl and sulfate radicals generated in the electrochemical system were the active species responsible for VFX degradation, which followed a first-order kinetic model with a rate constant of 0.0084 min−1. The main degradation intermediates were identified through LC-MS, including two isomers with a nominal m/z of 276 and three isomers with a nominal m/z of 294. The toxicity of the VFX degradation products was assessed by an in silico prediction model. This evaluation confirmed the sustainability of the developed method.

Tech Support

Original Source

DOI: https://doi.org/10.3390/molecules30091881

References

2022 - A review on emerging water contaminants and the application of sustainable removal technologies [Crossref]
2021 - Antidepressant drugs as emerging contaminants: Occurrence in urban and non-urban waters and analytical methods for their detection [Crossref]
2022 - Photochemical environmental persistence of venlafaxine in an urban water reservoir: A combined experimental and computational investigation [Crossref]
2016 - Effects of an antidepressant mixture on the brain serotonin and predation behavior of hybrid striped bass [Crossref]
2021 - A review of pharmaceutical occurrence and pathways in the aquatic environment in the context of a changing climate and the COVID-19 pandemic [Crossref]
2017 - Degradation of venlafaxine using TiO2/UV process: Kinetic studies, RSM optimization, identification of transformation products and toxicity evaluation [Crossref]