Enhanced electrooxidation of per and polyfluoroalkyl substances on Boron doped diamond anode in the presence of vacuum ultraviolet irradiation

At a Glance

Metadata	Details
Publication Date	2025-07-01
Journal	Scientific Reports
Authors	Yaye Wang, Haibo Xu, Ruoyang Li
Institutions	Hohai University, Nanjing University of Science and Technology
Citations	1
Analysis	Full AI Review Included

Enhanced PFAS Degradation via BDD Electrooxidation and VUV Irradiation

Technical Analysis and Material Solutions from 6CCVD

Executive Summary

This research successfully demonstrates a highly effective advanced oxidation process (AOP) for degrading persistent Per- and Polyfluoroalkyl Substances (PFASs) using a Boron-Doped Diamond (BDD) anode combined with Vacuum Ultraviolet (VUV) irradiation.

Core Achievement: The synergistic EO + VUV system significantly enhanced the degradation of PFOA and PFHxA compared to electrooxidation (EO) alone.
Kinetic Enhancement: Surface area normalized pseudo-first order rate constants increased by 37.2% for PFOA and 70.1% for PFHxA at a current density of 10 mA·cm^-2.
Mechanistic Insight: Time-Dependent Density Functional Theory (TDDFT) confirmed that VUV irradiation excites PFAS ions, reducing the energy difference (ΔE) required for electron loss, thereby accelerating the rate-limiting direct electron transfer (DET) process.
Material Requirement: Confirms the critical role of high-quality, high Oxygen Evolution Potential (OEP) Boron-Doped Diamond (BDD) anodes for efficient electrochemical PFAS destruction.
Real-World Efficacy: The EO + VUV system achieved 96.2% total PFAS removal in real industrial wastewater over 20 hours, demonstrating robust practical applicability.
Electrochemical Advantage: VUV irradiation lowered the required anodic potential for the oxygen evolution reaction from ~2.32 V vs SHE (EO only) to ~2.27 V vs SHE (EO + VUV).

Technical Specifications

The following hard data points were extracted from the experimental results characterizing the BDD anode performance and process efficiency.

Parameter	Value	Unit	Context
Anode Material	Boron-Doped Diamond (BDD)	N/A	MPCVD, coated on both sides
Anode Plate Dimensions	10 x 5	cm	Used in batch reactor
Anode Immersion Area	20	cm²	Single side area
Current Density Range	5 to 25	mA·cm^-2	Applied during electrooxidation
VUV Wavelength	185	nm	Low-pressure Hg lamp emission
VUV Power	20	W	VUV radiation source
PFOA Rate Constant Increase	37.2	%	EO+VUV vs EO at 10 mA·cm^-2
PFHxA Rate Constant Increase	70.1	%	EO+VUV vs EO at 10 mA·cm^-2
Total PFAS Removal (Wastewater)	96.2	%	After 20 hr EO+VUV treatment
Oxygen Evolution Potential (EO)	~2.32	V vs SHE	Measured via LSV in pure EO system
Oxygen Evolution Potential (EO+VUV)	~2.27	V vs SHE	Measured via LSV in synergistic system
BDD Grain Size	5 - 20	µm	Determined by SEM
Initial PFOA/PFHxA Concentration	1.00	mg·L^-1	Spiked reaction solution
Supporting Electrolyte	100	mM	Na₂SO₄

Key Methodologies

The experiment utilized a specialized electrochemical reactor setup integrating a high-performance BDD anode with a VUV source to achieve enhanced PFAS degradation.

Electrode Configuration: A BDD plate (10 cm x 5 cm) was used as the anode, positioned 0.50-cm from two titanium plates serving as cathodes. The BDD was coated on both sides, providing a 20 cm² immersion area (single side).
Electrochemical Control: A constant current density, ranging from 5 mA·cm^-2 to 25 mA·cm^-2, was applied using a controllable DC power source.
VUV Source: A 20 W, 185-nm low-pressure Hg lamp was integrated into the reactor to provide VUV irradiation, targeting the absorption range of PFOA/PFHxA ions (< 250 nm).
Solution Composition: Batch experiments used 400-mL solutions containing 1.00 mg·L^-1 of PFOA and PFHxA, supported by 100-mM Na₂SO₄ electrolyte. Real industrial wastewater samples were also tested without added electrolyte.
Process Monitoring: Anodic potential (AP) and linear sweep voltammetry (LSV) were used to characterize the electrochemical behavior and oxygen evolution potential (OEP) of the BDD anode.
Mechanistic Modeling: Time-Dependent Density Functional Theory (TDDFT) was employed to calculate the excited states and molar extinction coefficients of PFOA and PFHxA ions, confirming the VUV-induced acceleration of direct electron transfer.

6CCVD Solutions & Capabilities

6CCVD is the premier supplier of high-quality MPCVD diamond materials necessary to replicate, optimize, and scale this high-efficiency PFAS remediation technology. Our expertise in Boron-Doped Diamond (BDD) fabrication and customization directly addresses the requirements of advanced electrochemical AOPs.

Applicable Materials

To replicate or extend this research, high-quality, highly conductive BDD anodes are essential.

Heavy Boron-Doped PCD (Polycrystalline Diamond): This is the ideal material for high-current density electrochemical applications like the EO + VUV system. Our BDD electrodes offer the high OEP and chemical inertness required for efficient direct electron transfer and hydroxyl radical generation, ensuring maximum mineralization of persistent pollutants.
Custom PCD Plates: We offer PCD plates up to 125mm in diameter for large-scale reactor development, far exceeding the 10 cm x 5 cm plates used in the study.
Substrate Thickness: We provide robust BDD substrates up to 10mm thick, ensuring mechanical stability and longevity for industrial-scale flow cell designs.

Customization Potential

The success of this research relies on precise electrode geometry and stable electrical contacts. 6CCVD provides comprehensive customization services to meet these needs:

Research Requirement	6CCVD Customization Service	Technical Advantage
Specific Electrode Size/Shape	Custom Dimensions & Laser Cutting: We can supply BDD plates precisely cut to the required 10 cm x 5 cm dimensions, or any custom geometry needed for pilot or full-scale reactors.	Ensures optimal surface area loading and current distribution for specific reactor designs.
Stable Electrical Contact	In-House Metalization: We offer custom metal contacts (e.g., Ti, Pt, Au) applied directly to the BDD surface. This is critical for maintaining low resistance and stability, especially when exposed to VUV radiation and corrosive electrolytes.	Guarantees reliable, long-term electrical performance under harsh operating conditions.
Surface Morphology Control	Polishing and Surface Finish: While the paper used microcrystalline BDD (5-20 µm grain size), 6CCVD can control the surface roughness (Ra < 5nm for inch-size PCD) or provide specific grain sizes to allow researchers to optimize the electrode morphology for enhanced mass transfer or radical generation.	Enables fine-tuning of electrochemical kinetics based on surface structure.

Engineering Support

6CCVD’s in-house team of PhD material scientists and engineers specializes in diamond electrochemistry. We can assist researchers and industrial partners with:

Material Selection: Guidance on selecting the optimal boron doping level and diamond morphology (PCD vs. SCD) for specific PFAS degradation projects.
Electrode Design: Consultation on integrating BDD anodes into complex flow reactors, including metalization schemes and thermal management for VUV systems.
Scale-Up: Expertise in transitioning laboratory-scale BDD electrodes to large-format plates (up to 125mm) suitable for commercial wastewater treatment applications.
Global Logistics: Reliable global shipping (DDU default, DDP available) ensures timely delivery of custom BDD materials worldwide.

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

Tech Support

Original Source

DOI: https://doi.org/10.1038/s41598-025-07386-8

References

2015 - Toxicological Effects of Perfluoroalkyl and Polyfluoroalkyl Substances [Crossref]