Electro-Fenton-Based Technologies for Selectively Degrading Antibiotics in Aqueous Media

At a Glance

Metadata	Details
Publication Date	2022-05-31
Journal	Catalysts
Authors	Ángela Moratalla, Engracia Lacasa, Pablo Cañizares, Manuel A. Rodrigo, Cristina Sáez
Institutions	University of Castilla-La Mancha
Citations	6
Analysis	Full AI Review Included

Technical Documentation & Analysis: MPCVD Diamond for Advanced Oxidation Processes (AOPs)

Research Paper Analyzed: Electro-Fenton-Based Technologies for Selectively Degrading Antibiotics in Aqueous Media (Catalysts 2022, 12, 602)

Executive Summary

This research validates the superior performance of Boron-Doped Diamond (BDD) anodes in electrochemical advanced oxidation processes (EAOPs) for treating complex pharmaceutical wastewater.

Superior Degradation: BDD anodes achieved 100% removal of Penicillin G (PenG) in the Electro-Fenton (EF) process, significantly outperforming Mixed Metal Oxide (MMO) anodes (75.5% removal).
Effluent Quality Improvement: Treatment using BDD resulted in higher biodegradability and lower toxicity of the final effluent, reducing the E. faecalis antibiotic inhibition effect to 45% (compared to >90% for MMO).
Mechanism Confirmation: The results confirm BDD’s role in promoting hard oxidation conditions by generating quasi-free hydroxyl radicals, even under soft oxidation parameters (5 mA cm^-2).
Synergistic Enhancement: The Photoelectro-Fenton (PEF) process, combining EF with UVC irradiation (254 nm), demonstrated a strong synergistic effect, particularly boosting MMO performance (166.67% synergy coefficient).
Application Focus: The study confirms that BDD-based EAOPs are highly effective as a pretreatment step for conventional wastewater treatment plants (WWTPs) to mitigate chemical risk from persistent antibiotics.
Material Requirement: Successful replication and scaling of this technology require high-quality, custom-supported BDD electrodes, a core capability of 6CCVD.

Technical Specifications

The following hard data points were extracted from the experimental setup and results, highlighting the critical parameters for BDD performance in the Electro-Fenton system.

Parameter	Value	Unit	Context
Anode Material Tested	BDD or MMO-IrO₂Ta₂O₅	Material	Anode comparison for EF/PEF processes.
Current Density (j)	5	mA cm^-2	Soft oxidation conditions to favor H₂O₂ production.
Initial PenG Concentration	50	mg dm^-3	Target antibiotic concentration in synthetic urine.
Electric Charge Applied (Q)	0.10	Ah dm^-3	Charge required for primary degradation analysis.
PenG Removal (BDD-EF)	100	%	Complete removal achieved with BDD anode.
Antibiotic Inhibition (BDD-EF)	45	%	Final E. faecalis inhibition after BDD treatment.
BOD_ST Improvement (BDD-EF)	0.83	mg O₂ dm^-3	Short-term biodegradability increase.
PEF Synergy Coefficient (MMO)	166.67	%	Synergistic effect of UVC (9 W, 254 nm) coupling.
Interelectrode Gap (IE)	150	µm	Fixed distance in the microfluidic flow-through cell.
BDD Substrate Used	3D-Niobium Mesh	Material	Support structure for diamond deposition.

Key Methodologies

The experimental success hinges on precise control over the electrode materials and reactor configuration, particularly the use of BDD films on custom supports.

Anode Material Selection: Boron-Doped Diamond (BDD) films were deposited on 3D-niobium mesh, while Mixed Metal Oxide (MMO) films (IrO₂Ta₂O₅) were deposited on standard mesh.
Cathode Fabrication: Cathodes utilized 3D Titanium foam and mesh supports, coated with a mixture of Carbon Black (CB) and Polytetrafluoroethylene (PTFE) to optimize oxygen reduction and H₂O₂ generation.
Reactor Design: A microfluidic flow-through (MF-FT) cell was employed, integrated with a fluidized bed containing goethite (Fe catalyst) to facilitate the heterogeneous Fenton reaction.
Electrochemical Control: All tests were conducted under galvanostatic control at a low current density (5 mA cm^-2) to favor the two-electron oxygen reduction pathway (H₂O₂ formation) over the four-electron pathway (H₂O formation).
PEF Implementation: The Photoelectro-Fenton (PEF) process involved inserting a 9 W UVC lamp (254 nm) into the reservoir tank to induce photolysis of H₂O₂, generating additional hydroxyl radicals.
Analytical Techniques: High-performance liquid chromatography (HPLC) and LC-MS TOF were used to monitor PenG decay and identify complex degradation intermediates (e.g., C₁₆H₁₈N₂O₅S, C₁₄H₁₆N₂) and carboxylic acids.

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials and custom engineering required to replicate, scale, or extend this critical research in electrochemical wastewater treatment.

Applicable Materials

The core requirement of this research is a highly conductive, stable anode material capable of generating hydroxyl radicals efficiently.

Research Requirement	6CCVD Solution	Technical Advantage
High-Performance Anode	Heavy Boron-Doped Diamond (BDD)	Tunable doping levels ensure optimal conductivity and maximized hydroxyl radical (•OH) generation for hard oxidation, leading to superior contaminant removal and effluent quality (100% PenG removal demonstrated).
Custom Substrate Support	BDD on Niobium or Titanium	We offer BDD deposition on custom conductive substrates (Nb, Ti, W, Si) up to 125mm in diameter, matching the specific 3D mesh/foam supports used in the MF-FT reactor design.
Thin Film Control	SCD/PCD/BDD Films	We provide precise thickness control for BDD films (0.1 µm to 500 µm), allowing researchers to optimize the electrode surface area and electrochemical properties for specific current densities (e.g., 5 mA cm^-2).

Customization Potential

The complexity of the MF-FT cell and the need for specialized cathode coatings align perfectly with 6CCVD’s custom fabrication services.

Custom Dimensions and Geometry: 6CCVD can supply BDD plates and wafers up to 125mm, or custom-cut geometries required for microfluidic flow-through (MF-FT) cells, ensuring precise fit for interelectrode gaps as small as 150 µm.
Advanced Metalization Services: The paper utilized complex Ti/CB/PTFE cathodes. 6CCVD offers in-house metalization capabilities (Au, Pt, Pd, Ti, W, Cu) for creating robust contact layers or specialized electrode structures, simplifying the integration of diamond films into complex electrochemical systems.
Surface Finish Optimization: For applications requiring high purity and minimal fouling, 6CCVD provides ultra-smooth polishing (Ra < 1nm for SCD, < 5nm for inch-size PCD), ensuring long-term stability and performance in aggressive media like synthetic urine.

Engineering Support

6CCVD’s in-house PhD team provides authoritative support for advanced electrochemical projects.

EAOP Optimization: Our experts can assist researchers and engineers in selecting the optimal BDD doping concentration and film thickness to balance the generation of hydroxyl radicals (for hard oxidation) and hydrogen peroxide (for Fenton processes), crucial for selective degradation applications like antibiotic wastewater pretreatment.
Scale-Up Consultation: We offer technical consultation on transitioning lab-scale MF-FT reactor designs to industrial scale, leveraging our capability to produce large-area BDD electrodes (up to 125mm).

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

View Original Abstract

The viability of the Electro-Fenton (EF) process in the selective degradation of penicillin G (PenG) in complex solutions has been studied. The role of the anode material (boron-doped diamond (BDD) or mixed metal oxide (MMO)) and the cathode 3D support (foam or mesh), as well as the synergistic effect of UVC light irradiation (photoelectron-Fenton, PEF), have been evaluated. The results show that Pen G can be efficiently and selectively removed by EF, obtaining higher PenG removal rates when using the BDD anode (100%) than when using the MMO anode (75.5%). Additionally, mineralization is not favored under the experimental conditions tested (pH 3, 5 mA cm−2), since both aromatic and carboxylic acids accumulate in the reaction system as final products. In this regard, the EF-treated solution presents a high biological oxygen demand and a low percentage of Vibrio fischeri inhibition, which leads to high biodegradability and low toxicity of this final effluent. Furthermore, the combination with UVC radiation in the PEF process shows a clear synergistic effect on the degradation of penicillin G: 166.67% and 83.18% using MMO and BBD anodes, respectively. The specific energy required to attain the complete removal of PenG and high inhibition of the antibiotic effect is less than 0.05 Ah dm−3. This confirms that PEF can be efficiently used as a pretreatment of conventional wastewater treatment plants to decrease the chemical risk of complex solutions polluted with antibiotics.

Tech Support

Original Source

DOI: https://doi.org/10.3390/catal12060602

References

2019 - Pharmaceuticals of Emerging Concern in Aquatic Systems: Chemistry, Occurrence, Effects, and Removal Methods [Crossref]
2021 - Novel Ti/RuO2IrO2 anode to reduce the dangerousness of antibiotic polluted urines by Fenton-based processes [Crossref]
2006 - Toxicity and biodegradability assessment of raw and ozonated procaine penicillin G formulation effluent [Crossref]
2014 - Electro-Fenton degradation of the antibiotic sulfanilamide with Pt/carbon-felt and BDD/carbon-felt cells. Kinetics, reaction intermediates, and toxicity assessment [Crossref]
2021 - Photocatalytic performance of Ti/MMO/ZnO at degradation of levofloxacin: Effect of pH and chloride anions [Crossref]
2019 - The impact of on-site hospital wastewater treatment on the downstream communal wastewater system in terms of antibiotics and antibiotic resistance genes [Crossref]
2017 - Degradation of pharmaceutical diclofenac and ibuprofen in aqueous solution, a direct comparison of ozonation, photocatalysis, and non-thermal plasma [Crossref]
2021 - Degradation of micropollutant cephalexin by ultraviolet (UV) and assessment of residual antimicrobial activity of transformation products [Crossref]