Sustainable Degradation of Acetaminophen by a Solar-Powered Electro-Fenton Process - A Green and Energy-Efficient Approach

At a Glance

Metadata	Details
Publication Date	2025-08-20
Journal	Processes
Authors	Sonia Herrera-Chávez, Silvia Gutiérrez‐Granados, Miguel A. Sandoval, Enric Brillas, Martín Pacheco‐Álvarez
Institutions	Universitat de Barcelona, Tecnológico Nacional de México
Citations	1
Analysis	Full AI Review Included

Technical Documentation & Analysis: Sustainable ACTP Degradation using BDD Electrodes

Executive Summary

This research validates the critical role of Boron-Doped Diamond (BDD) electrodes in achieving highly efficient and sustainable pharmaceutical wastewater treatment via Advanced Oxidation Processes (AOPs).

Superior Performance: The Solar Photo-Electro-Fenton (SPEF) process utilizing BDD/BDD electrodes achieved 97% Acetaminophen (ACTP) removal and 78% Chemical Oxygen Demand (COD) reduction within 90 minutes.
Material Validation: BDD was confirmed as the optimal anode material, facilitating the generation of highly reactive hydroxyl radicals (*OH) and secondary oxidants (e.g., peroxydisulfate, S₂O₈^2-) necessary for complete mineralization.
Energy Efficiency: SPEF demonstrated exceptional energy efficiency, requiring only ~0.052 kWh per gram of COD removed (kWh gCOD^-1), highlighting its potential as a cost-effective, green technology.
Kinetic Control: Degradation followed pseudo-first-order kinetics, with the maximum rate constant (0.0865 min^-1) achieved under optimized conditions, confirming mass-transport-controlled regimes.
Sustainability Focus: The integration of natural solar UV-A radiation (30-35 W m^-2) enhanced oxidant regeneration (Fe³⁺ to Fe²⁺ photoreduction) and accelerated the breakdown of recalcitrant intermediates like phenol and catechol.
Electrode Longevity: The study confirms that BDD electrodes maintain integrity under high current densities (up to 60 mA cm^-2), with treatment durations consuming less than 0.2% of the estimated median lifespan (>782 h).

Technical Specifications

Parameter	Value	Unit	Context
Anode Material	Boron-Doped Diamond (BDD)	N/A	Used for all AOPs (EO, EF, SPEF)
Cathode Material	BDD or Graphite	N/A	BDD/BDD configuration for SPEF/EF
Optimal Current Density (j)	60	mA cm^-2	Maximized radical generation
ACTP Removal (SPEF)	97	%	Achieved in 60 min
COD Reduction (SPEF)	78	%	Achieved in 90 min
Energy Oxidation Index (EOI)	~0.052	kWh gCOD^-1	Low specific energy consumption
Maximum Kinetic Constant (K_c)	0.0865	min^-1	Pseudo-first-order rate (SPEF)
Initial ACTP Concentration (C₀)	10-30	mg L^-1	Range tested
Optimal pH	3.0	N/A	Adjusted with H₂SO₄
Fe²⁺ Catalyst Concentration	0.05	mmol L^-1	Used in EF and SPEF
Solar UV-A Irradiation	30-35	W m^-2	Natural sunlight source (300-400 nm)
Supporting Electrolyte	0.05 M	Na₂SO₄	Maintained constant conditions
Interelectrode Distance	2	cm	Reduced system resistance

Key Methodologies

The study systematically compared Electro-Oxidation (EO), Electro-Fenton (EF), and Solar Photo-Electro-Fenton (SPEF) processes using BDD electrodes under controlled conditions.

Electrode Setup: Experiments utilized a 250 mL stirred-tank reactor. EO employed a BDD anode and a Graphite cathode (BDD/Graphite), while EF and SPEF used BDD as both anode and cathode (BDD/BDD).
Electrolyte Conditions: Solutions were maintained at pH 3.0, adjusted using H₂SO₄, with 0.05 M Na₂SO₄ serving as the supporting electrolyte.
Current Density Control: Applied current density (j) was varied between 15 and 60 mA cm^-2 using a BK PRECISION MODEL 1665 power source.
Fenton Catalyst Dosing: Ferrous sulfate heptahydrate (FeSO₄ 7H₂O) was added to EF and SPEF systems, with concentrations ranging from 0.1 to 0.5 mmol L^-1.
Solar Irradiation: SPEF trials were conducted under natural summer sunlight, providing UV-A radiation measured at 30-35 W m^-2.
Optimization Strategy: A three-level Box-Behnken experimental design was implemented to optimize the degradation rate constant (K_c) based on electrolysis time, initial ACTP concentration, and applied current density.
Analytical Monitoring: ACTP degradation and intermediate formation (phenol, catechol) were monitored using UV-Vis spectrophotometry and High-Performance Liquid Chromatography (HPLC). Mineralization was tracked via Chemical Oxygen Demand (COD) assays.

6CCVD Solutions & Capabilities

The successful implementation of high-performance SPEF relies fundamentally on the quality and stability of the Boron-Doped Diamond (BDD) electrodes. 6CCVD is an expert supplier of MPCVD diamond materials, perfectly positioned to meet the stringent requirements of this research and future industrial scale-up.

Research Requirement	6CCVD Material Solution & Customization Potential
High-Performance BDD Anodes	Heavy Boron Doped PCD Wafers: We supply Polycrystalline Diamond (PCD) wafers with precise, heavy boron doping optimized for electrochemical AOPs. This ensures maximum overpotential for efficient *OH radical generation and secondary oxidant (S₂O₈^2-) formation, critical for the observed high mineralization rates.
Custom Electrode Dimensions	Plates up to 125mm: 6CCVD offers custom BDD plates and wafers up to 125mm in diameter, allowing researchers to transition seamlessly from lab-scale (250 mL reactor) to pilot-scale flow systems. We provide thicknesses from 0.1µm to 500µm.
BDD/BDD Configuration	Matched Electrode Sets: We can supply matched BDD anode and cathode sets (BDD/BDD) engineered for the specific current densities (up to 60 mA cm^-2) and acidic environments (pH 3.0) required for optimal Electro-Fenton performance.
Electrode Integration & Contact	Custom Metalization Services: For robust electrical contact and integration into reactor systems, 6CCVD offers in-house metalization capabilities, including Ti, Pt, Au, Pd, W, and Cu layers, ensuring low resistance connections for high current operation.
Surface Quality for Longevity	Superior Polishing: Our inch-size PCD wafers feature polishing down to Ra < 5nm, minimizing surface defects and maximizing the estimated electrode lifespan (>782 h) under continuous operation.
Global Supply Chain	Worldwide Shipping: 6CCVD provides reliable global shipping (DDU default, DDP available) to ensure researchers and engineers worldwide can access high-quality MPCVD diamond materials quickly and efficiently.

Engineering Support

6CCVD’s in-house PhD team specializes in electrochemical material science and can assist researchers in selecting the optimal BDD doping concentration, substrate geometry, and metalization scheme required to replicate or extend this highly efficient Solar Photo-Electro-Fenton (SPEF) technology for similar pharmaceutical wastewater treatment projects.

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

View Original Abstract

The presence of acetaminophen (ACTP) in aquatic environments has become a significant concern due to its environmental persistence and the potential formation of toxic transformation products. This study systematically compares the performance of three electrochemical advanced oxidation processes (EAOPs), electro-oxidation (EO), electro-Fenton (EF), and solar photo-electro-Fenton (SPEF), for the degradation and mineralization of ACTP in aqueous media using boron-doped diamond (BDD) electrodes. Reactions were conducted under varying operational parameters, including current densities (15-60 mA cm−2), initial ACTP concentrations (10-30 mg L−1), and Fe2+ dosages. In the SPEF system, natural sunlight was utilized as the source of UV-A irradiation (30-35 W m−2). Among the evaluated processes, SPEF exhibited the highest degradation efficiency, achieving up to 97% ACTP removal and 78% chemical oxygen demand (COD) reduction within 90 min. High-performance liquid chromatography (HPLC) analysis identified phenol and catechol as major intermediates, suggesting a degradation pathway involving hydroxylation, aromatic ring cleavage, and subsequent oxidation into low-molecular-weight carboxylic acids. Kinetic modeling revealed pseudo-first-order behavior, with a maximum rate constant of 0.0865 min−1 under optimized conditions determined via Box-Behnken experimental design. Additionally, SPEF demonstrated enhanced energy efficiency (~0.052 kWh gCOD−1) and improved oxidant regeneration under solar radiation, highlighting its potential as an environmentally friendly and cost-effective alternative for pharmaceutical wastewater treatment. These results support the implementation of SPEF as a sustainable strategy for mitigating the environmental impact of emerging contaminants, especially in regions with high solar availability and limited technological resources.

Tech Support

Original Source

DOI: https://doi.org/10.3390/pr13082633

References

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2025 - Advanced Oxidation Process-Mediated Removal of Pharmaceuticals from Water: A Review of Recent Advances
2012 - Degradation of acetaminophen by Fenton and electro-Fenton processes in aerator reactor [Crossref]
2023 - Development of heterogeneous electro-Fenton process with immobilized FeWO4 catalyst for degradation of tetracycline and crude-oil tank cleaning wastewater [Crossref]
2011 - Photo-Fenton mineralization of synthetic municipal wastewater effluent containing acetaminophen in a pilot plant [Crossref]