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6CCVD Research

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

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2025-08-20
JournalProcesses
AuthorsSonia Herrera-ChĂĄvez, Silvia GutiĂ©rrez‐Granados, Miguel A. Sandoval, Enric Brillas, MartĂ­n Pacheco‐Álvarez
InstitutionsUniversidad de Guanajuato, TecnolĂłgico Nacional de MĂ©xico
Citations1
AnalysisFull AI Review Included

Executive Summary

Section titled “Executive Summary”

This study validates the Solar Photo-Electro-Fenton (SPEF) process using Boron-Doped Diamond (BDD) electrodes as a highly efficient and sustainable technology for degrading acetaminophen (ACTP).

  • Superior Performance: SPEF demonstrated a clear efficiency hierarchy (SPEF > EF > EO), achieving up to 97% ACTP removal and 78% Chemical Oxygen Demand (COD) reduction within 90 minutes.
  • Energy Efficiency: SPEF exhibited significantly enhanced energy efficiency, requiring only ~0.052 kWh per gram of COD removed (gCOD-1), highlighting its cost-effectiveness.
  • Synergistic Mechanism: The high performance is attributed to the synergistic action of BDD anodic oxidation, homogeneous electro-Fenton reactions, and natural solar UV irradiation, which continuously regenerates the Fe2+ catalyst.
  • Optimal Conditions: Optimization via Box-Behnken design identified the optimal conditions: 60 mA cm-2 current density, 10 mg L-1 initial ACTP concentration, and 60-90 minutes electrolysis time.
  • Reaction Kinetics: The degradation followed pseudo-first-order kinetics, with a maximum rate constant (Kc) of 0.0865 min-1 under optimized SPEF conditions.
  • Degradation Pathway: HPLC confirmed the transient formation of Phenol and Catechol, indicating a pathway involving hydroxylation, aromatic ring cleavage, and subsequent oxidation to low-molecular-weight carboxylic acids.
  • Sustainability: The use of natural solar radiation makes SPEF a viable, environmentally friendly alternative for treating pharmaceutical contaminants, particularly in regions with high solar availability.

Technical Specifications

Section titled “Technical Specifications”
ParameterValueUnitContext
Optimal ACTP Removal (SPEF)97%Achieved in 60 min (10 mg L-1 ACTP)
Optimal COD Reduction (SPEF)78%Achieved in 90 min (10 mg L-1 ACTP)
Specific Energy Consumption (SEC)0.052kWh gCOD-1Calculated after 90 min treatment
Optimal Current Density (j)60mA cm-2Maximized radical generation rate
Optimal Initial ACTP Conc. (C0)10mg L-1Used for maximum fractional removal
Optimal Fe2+ Dosage0.05mmol L-1Used in EF and SPEF processes
Optimal pH3.0-Maintained using H2SO4
Supporting Electrolyte Conc.0.05MNa2SO4
Solar UV-A Irradiation Intensity30-35W/m2Natural sunlight (300-400 nm)
Maximum Kinetic Constant (Kc)0.0865min-1Pseudo-first-order rate (optimized SPEF)
Current Efficiency Index (ICE)3.2-Measured after 90 min treatment
Electrode Lifespan Estimate (BDD)782hMedian lifetime at 10-50 mA cm-2

Key Methodologies

Section titled “Key Methodologies”
  1. Electrochemical Cell Setup: Experiments were performed in a 250 mL stirred-tank reactor, continuously stirred at 60 rpm, with constant oxygen supply via an air pump.
  2. Electrode Materials and Configuration:
    • EO: BDD (anode) / Graphite (cathode).
    • EF/SPEF: BDD (anode) / BDD (cathode).
    • Interelectrode distance was maintained at approximately 2 cm.
  3. Chemical Environment: Solutions were prepared using ultrapure water, maintained at pH 3.0 (adjusted with H2SO4), and utilized 0.05 M Na2SO4 as the supporting electrolyte. Ferrous sulfate (FeSO4·7H2O) was added for Fenton processes (0.05 mmol L-1).
  4. Solar Irradiation Source: SPEF trials were conducted outdoors during the summer of 2023, utilizing natural UV radiation (300-400 nm) measured by a Kipp & Zonen CUV 5 radiometer (30-35 W/m2).
  5. Process Optimization: A three-level Box-Behnken experimental design (RSM) was used to model and optimize the degradation rate constant (Kc) based on three independent variables: electrolysis time (30-90 min), initial ACTP concentration (10-30 mg L-1), and applied current density (20-60 mA cm-2).
  6. Analytical Techniques:
    • ACTP concentration was monitored by UV-Vis spectrophotometry (243 nm) and High-Performance Liquid Chromatography (HPLC) using a Zorbax SB-C18 column (isocratic method, 50:50 acetonitrile:water).
    • Mineralization was quantified by Chemical Oxygen Demand (COD) assays (Standard Methods 5220D).
    • Intermediate products (Phenol, Catechol) were identified via HPLC.

Commercial Applications

Section titled “Commercial Applications”

The findings support the implementation of BDD-based SPEF technology in several high-value environmental engineering sectors:

  • Pharmaceutical Wastewater Treatment: Direct application for the efficient and cost-effective removal and mineralization of persistent pharmaceutical contaminants (like ACTP) from industrial and hospital effluents.
  • Decentralized Water Remediation Systems: SPEF is highly suitable for deployment in remote or resource-constrained regions, leveraging natural solar energy to reduce operational costs and reliance on complex infrastructure.
  • Advanced Oxidation Reactor Design: The BDD electrode material is critical for high-performance AOPs, offering superior stability and high current density operation necessary for generating adsorbed hydroxyl radicals (BDD(‱OH)).
  • Refractory Organic Mineralization: Used for treating complex industrial wastewaters (e.g., textile, tanning) where stable aromatic intermediates and short-chain carboxylic acids must be fully mineralized to meet strict discharge limits.
  • Sustainable Engineering Solutions: Provides a green technology alternative to conventional chemical or energy-intensive treatments, aligning with sustainable development goals for water quality management.
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

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2012 - Modelling photo-Fenton process for organic matter mineralization, hydrogen peroxide consumption and dissolved oxygen evolution
  2. 2016 - Efficient removal of paracetamol using LaCu1−xMxO3 (M = Mn, Ti) perovskites as heterogeneous Fenton-like catalysts [Crossref]
  3. 2021 - Aluminized surface to improve solar light absorption in open reactors: Application for micropollutants removal in effluents from municipal wastewater treatment plants [Crossref]
  4. 2023 - The occurrence and fate of antibiotics and nonsteroidal anti-inflammatory drugs in water treatment processes: A review
  5. 2019 - Acetaminophen micropollutant: Historical and current occurrences, toxicity, removal strategies and transformation pathways in different environments [Crossref]
  6. 2020 - Removal of Pharmaceutical Contaminants from Aqueous Medium: A State-of-the-Art Review Based on Paracetamol [Crossref]
  7. 2025 - Advanced Oxidation Process-Mediated Removal of Pharmaceuticals from Water: A Review of Recent Advances
  8. 2012 - Degradation of acetaminophen by Fenton and electro-Fenton processes in aerator reactor [Crossref]
  9. 2023 - Development of heterogeneous electro-Fenton process with immobilized FeWO4 catalyst for degradation of tetracycline and crude-oil tank cleaning wastewater [Crossref]
  10. 2011 - Photo-Fenton mineralization of synthetic municipal wastewater effluent containing acetaminophen in a pilot plant [Crossref]

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