Hybrid Solar Photoelectro-Fenton and Ozone Processes for the Sustainable Removal of COVID-19 Pharmaceutical Contaminants

At a Glance

Metadata	Details
Publication Date	2025-10-10
Journal	Processes
Authors	Sonia Herrera-Chávez, Martín Pacheco‐Álvarez, Luis A. Godı́nez, Enric Brillas, Juan M. Peralta‐Hernández
Institutions	Autonomous University of Queretaro, Tecnológico Nacional de México
Analysis	Full AI Review Included

Technical Analysis of Hybrid Solar Photoelectro-Fenton Processes using BDD Electrodes

This document analyzes the research paper “Hybrid Solar Photoelectro-Fenton and Ozone Processes for the Sustainable Removal of COVID-19 Pharmaceutical Contaminants” to highlight the critical role of Boron-Doped Diamond (BDD) electrodes and connect the experimental requirements to 6CCVD’s advanced MPCVD diamond capabilities.

Executive Summary

The research successfully demonstrated a scalable, sustainable approach for wastewater remediation using a hybrid Advanced Electrochemical Oxidation Process (EAOP) based on Boron-Doped Diamond (BDD) electrodes coupled with solar irradiation and ozone.

Core Technology: Pilot-scale Solar Photoelectro-Fenton (SPEF) and SPEF/O₃ systems utilizing a BDD/BDD electrode configuration in a filter-press cell and a Compound Parabolic Collector (CPC) photoreactor.
Material Performance: BDD electrodes enabled high current density operation (60 mA cm^-2) for efficient in-situ electrogeneration of H₂O₂, driving the Fenton reaction.
High Degradation Efficiency: Achieved complete (100%) degradation of the model pharmaceutical, paracetamol, in approximately 50 minutes.
Mineralization Success: The SPEF process resulted in a high Chemical Oxygen Demand (COD) removal of 78% within 90 minutes.
Energy Efficiency: Demonstrated a low specific energy consumption (EC_COD) of 0.0519 kWh (g COD)^-1, highlighting the economic viability of the solar-assisted process.
Complex Matrix Treatment: The SPEF/O₃ hybrid system successfully degraded a complex mixture of four recalcitrant COVID-19 related pharmaceuticals (dexamethasone, amoxicillin, azithromycin).
Scalability: The system uses commercially available BDD electrodes and CPC photoreactors, confirming technical feasibility for large-scale environmental remediation.

Technical Specifications

The following hard data points were extracted from the optimal experimental conditions for the Solar Photoelectro-Fenton (SPEF) process using BDD electrodes:

Parameter	Value	Unit	Context
Electrode Material	BDD/BDD	N/A	Anode and Cathode configuration
Electrode Geometric Area	64	cm²	Area of each electrode in the filter-press cell
Working Volume	30	L	Pilot-scale continuous flow reactor
Optimal Current Density (j)	60	mA cm^-2	Selected for maximum H₂O₂ production
Initial Paracetamol Concentration	20	mg L^-1	Used for SPEF degradation tests
Time for 100% Degradation	~50	min	Paracetamol removal via SPEF
COD Removal Efficiency	78	%	Achieved after 90 min of SPEF treatment
Specific Energy Consumption (EC_COD)	0.0519	kWh (g COD)^-1	Measured at 90 min electrolysis time
Faradaic Efficiency (η)	8	%	Measured at j = 60 mA cm^-2, 90 min
Supporting Electrolyte	0.05	M Na₂SO₄	Used to maintain conductivity
Catalyst Concentration	0.5	mM Fe²⁺	Required for the Fenton reaction
Operating pH	3.0	N/A	Optimized for Fenton chemistry
UV-A Radiation Intensity	30 - 35	W m^-2	Natural solar irradiation (300-400 nm)

Key Methodologies

The following steps outline the critical parameters and setup used to achieve high-efficiency pharmaceutical degradation:

Electrochemical Cell Setup: A filter-press reactor was employed, fitted with Boron-Doped Diamond (BDD) electrodes (64 cm² geometric area each) acting as both anode and cathode, separated by a 1.5 cm gap.
Reactor Configuration: The system utilized a 30 L working volume, continuously recirculated at 300 L h^-1 through a CPC-type photoreactor to maximize solar light capture.
Electrolyte and Catalyst: The solution contained 0.05 M Na₂SO₄ as the supporting electrolyte and 0.5 mM Fe²⁺ (from FeSO₄·7H₂O) as the Fenton catalyst, with the pH maintained at 3.0.
Current Application: Continuous DC current was supplied by a B.K. Precision 1688B DC supply, with the optimal current density selected at 60 mA cm^-2 to maximize H₂O₂ electrogeneration.
Ozone Integration: For hybrid SPEF/O₃ trials, ozone gas (generated from dry air, max capacity 7 L min^-1) was bubbled into the solution via a glass diffuser in the CPC photoreactor.
Electrode Activation: Prior to trials, BDD electrodes underwent a cleaning and activation protocol involving applying 100 mA cm^-2 in 0.05 M Na₂SO₄ solution for 120 minutes to ensure optimal performance.

6CCVD Solutions & Capabilities

6CCVD specializes in providing the high-quality, custom MPCVD diamond materials essential for replicating and advancing this type of high-efficiency EAOP research. Our capabilities directly address the material requirements demonstrated in this study, ensuring seamless transition from pilot-scale demonstration to industrial application.

Research Requirement	6CCVD Solution & Capability	Technical Advantage for Replication/Scale-Up
High-Purity BDD Electrodes	Boron-Doped Diamond (BDD) Material: We supply highly conductive, robust BDD films grown via Microwave Plasma Chemical Vapor Deposition (MPCVD).	Guarantees the high overpotential necessary for efficient hydroxyl radical (*OH) generation and sustained H₂O₂ production at the cathode (Equation 2).
Custom Electrode Dimensions	Custom Dimensions & Fabrication: 6CCVD manufactures BDD plates and wafers up to 125 mm (PCD/BDD).	Supports the scale-up of the filter-press reactor design, allowing engineers to specify exact electrode geometries (e.g., larger than the 64 cm² used) for increased throughput.
Optimized Film Thickness	Precise Thickness Control: SCD/PCD/BDD films available from 0.1 µm up to 500 µm.	Enables optimization of BDD film thickness to balance conductivity, cost, and longevity under aggressive, high current density conditions (j = 60 mA cm^-2).
Robust Electrical Interfacing	In-House Metalization Services: We offer custom metalization stacks (Au, Pt, Pd, Ti, W, Cu) tailored for electrochemical environments.	Ensures reliable, low-resistance electrical contacts, crucial for maintaining the high current densities required for efficient SPEF operation without degradation of the contact pads.
Surface Quality and Activation	Advanced Polishing: BDD surfaces polished to Ra < 5 nm (for inch-size PCD/BDD).	Provides a consistent, high-quality surface finish, minimizing the need for extensive pre-trial activation protocols (120 min at 100 mA cm^-2) and maximizing operational stability.
Global Logistics	Global Shipping: Standard DDU shipping worldwide, with DDP options available upon request.	Ensures rapid and reliable delivery of custom BDD electrodes to research facilities and industrial partners globally, supporting international collaboration and deployment.

Engineering Support

6CCVD’s in-house team of PhD material scientists and electrochemical engineers can assist researchers and industrial partners in selecting the optimal BDD doping levels, film thickness, and substrate configuration required to replicate or extend this hybrid SPEF/O₃ technology for similar pharmaceutical wastewater remediation projects.

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

View Original Abstract

This study explores a hybrid advanced electrochemical oxidation process (EAOP) intensified by solar irradiation and ozone for the treatment of wastewater containing COVID-19-related pharmaceuticals. Pilot-scale trials were performed in a 30 L compound parabolic collector (CPC)-type photoreactor with a boron-doped diamond (BDD-BDD) electrode configuration. Under optimal conditions (50 mg L−1 paracetamol, 0.05 M Na2SO4, 0.50 mM Fe2+, pH 3.0, and 60 mA cm−2), the solar photoelectro-Fenton (SPEF) process achieved 78% chemical oxygen demand (COD) reduction within 90 min, with catechol and phenol detected as the main aromatic intermediates. When applied to a four-drug mixture (dexamethasone, paracetamol, amoxicillin, and azithromycin), the solar photoelectro-Fenton (SPEF-ozone (O3)) system reached 60% degradation and 41% COD removal under solar conditions. The results highlight the synergistic effect of ozone and solar energy in enhancing the electrochemical oxidation process (EAOP) performance and demonstrate the potential of these processes for scalable and sustainable removal of pharmaceutical contaminants from wastewater.

Tech Support

Original Source

DOI: https://doi.org/10.3390/pr13103234

References

2020 - COVID-19 in patients on maintenance dialysis in the Paris region [Crossref]
2021 - Dexamethasone: Therapeutic potential, risks, and future projection during COVID-19 pandemic [Crossref]
2024 - A qualitative exploration of purchasing, stockpiling, and use of drugs during the COVID-19 pandemic in an urban city of Bangladesh [Crossref]
2022 - Egyptian perspectives on potential risk of paracetamol/acetaminophen-induced toxicities: Lessons learnt during COVID-19 pandemic [Crossref]
2023 - Comparison of methylprednisolone pulse vs conventional dexamethasone for adult cases of COVID-19 requiring oxygen; a Japanese retrospective cohort study [Crossref]
2021 - Effects of acetaminophen on outcomes in patients hospitalized with COVID-19 [Crossref]
2021 - Photo-mediated and advanced oxidative processes applied for the treatment of effluents with drugs used for the treatment of early COVID-19: Review [Crossref]
2022 - Drugs used during the COVID-19 first wave in Vitoria-Gasteiz (Spain) and their presence in the environment [Crossref]
2021 - Automedicação e uso indiscriminado de medicamentos durante a pandemia da COVID-19 [Crossref]
2022 - Paracetamol—A contaminant of high concern: Existence in environment and adverse effect