Degradation of pesticide Cartap in Padan 95SP by combined advanced oxidation and electro-Fenton process

At a Glance

Metadata	Details
Publication Date	2020-05-06
Journal	Journal of Solid State Electrochemistry
Authors	Nguyen Tien Hoang, Rudolf Holze
Institutions	Chemnitz University of Technology
Citations	27
Analysis	Full AI Review Included

Technical Analysis: BDD Electrodes for Advanced Oxidation Processes (AOPs)

This document analyzes the application of Boron-Doped Diamond (BDD) electrodes in a modified electro-Fenton process for the efficient degradation and mineralization of the pesticide Cartap (Padan 95SP). The findings confirm BDD’s critical role in generating highly oxidative hydroxyl radicals (•OH) for water remediation, aligning perfectly with 6CCVD’s core material science offerings.

Executive Summary

High Efficiency BDD Anode: The study successfully utilized a Boron-Doped Diamond (BDD) thin-film electrode in a one-compartment cell, combining anodic oxidation and electro-Fenton processes for water treatment.
Rapid Degradation: Near-quantitative decomposition of the target pesticide, Cartap, was achieved within the initial 5 minutes of electrolysis, demonstrating the high reactivity of the BDD-generated •OH radicals.
Mineralization Success: The combined process achieved approximately 80% Total Organic Carbon (TOC) removal after 120 minutes, indicating significant mineralization of the organic pollutant.
Optimized Parameters: Key operating conditions were identified, including an optimal current density of 20 mA cm^-2, pH 3, and specific concentrations of H₂O₂ (0.2 M) and Fe²⁺ (10 mM).
Co-Catalyst Performance: Copper ions (Cu²⁺) were found to accelerate TOC removal in the early stages (first 30 min) more effectively than Fe²⁺, Mg²⁺, or Al³⁺, highlighting opportunities for customized catalyst systems.
Refractory Intermediates: The remaining 20% TOC limitation is attributed to recalcitrant intermediate products that resist further oxidation by •OH, emphasizing the need for robust, high-performance BDD materials.

Technical Specifications

The following hard data points were extracted from the experimental setup and results:

Parameter	Value	Unit	Context
Electrode Material	Boron-Doped Diamond (BDD)	N/A	Working/Positive Electrode (Anode)
BDD Coating Thickness	2.5 - 3	µm	Thin-film deposition on substrate
Exposed Surface Area	3.8	cm²	Circular geometry
Current Density (j)	20	mA cm^-2	Optimal constant current applied
Initial Cartap Concentration	700	mg L^-1	Padan 95SP solution
Initial TOC Concentration	215	mg L^-1	Total Organic Carbon equivalent
Optimal Solution pH	3	N/A	Maintained for Fenton reaction
Optimal H₂O₂ Concentration	0.2	M	Added oxidant concentration
Optimal Fe²⁺ Concentration	10	mM	Fenton catalyst concentration
Maximum TOC Removal	~80	%	Achieved after 120 min treatment
Operating Temperature	22	°C	Room temperature operation

Key Methodologies

The degradation of Cartap was achieved using a modified electro-Fenton process enhanced by the BDD anode’s high oxidative power.

Electrolysis Setup: Bulk electrolysis was conducted in a 400-mL one-compartment cell using a BDD working electrode, a platinum foil counter electrode, and a Ag/AgCl reference electrode.
Electrode Pre-treatment: The BDD electrode was subjected to 5 minutes of ultrasound cleaning to remove surface contaminants prior to use.
Electrolyte Preparation: The solution consisted of 700 mg L^-1 Padan 95SP and 0.05 M Na₂SO₄ as the supporting electrolyte.
pH Adjustment: The solution pH was initially adjusted to 3 (the optimal value for the Fenton reaction) using H₂SO₄ and NaOH.
Modified Electro-Fenton: Hydrogen peroxide (H₂O₂, 0.2 M) and ferrous ions (Fe²⁺, 10 mM) were added directly to the solution, simplifying the setup by omitting the gas-fed oxygen-consuming cathode typically used for in situ H₂O₂ generation.
Operation: A constant current density of 20 mA cm^-2 was applied for 120 minutes.
Analytical Techniques: Cartap concentration was determined via UV-vis spectroscopy (412 nm) using the 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB) procedure. Mineralization was tracked by measuring Total Organic Carbon (TOC) content.

6CCVD Solutions & Capabilities

This research validates the necessity of high-quality, customized Boron-Doped Diamond (BDD) electrodes for high-performance electrochemical Advanced Oxidation Processes (EAOPs). 6CCVD is uniquely positioned to supply the materials and engineering support required to replicate, scale, and advance this research.

Applicable Materials

To replicate or extend this high-efficiency electro-Fenton system, researchers require robust, highly conductive BDD thin-film electrodes.

Research Requirement	6CCVD Solution	Material Specification
High Oxidative Power	Heavy Boron-Doped Diamond (BDD)	Polycrystalline (PCD) or Single Crystal (SCD) thin films optimized for •OH generation.
Thin Film Requirement	Precision Thickness Control	BDD films available from 0.1 µm up to 500 µm. The required 2.5-3 µm thickness is standard.
Large Area/Scale-up	Large Format PCD Wafers	PCD plates/wafers available up to 125 mm diameter for pilot-scale reactors and industrial applications.
Surface Quality	Electrochemical Grade Polishing	Polishing capability for PCD surfaces to Ra < 5 nm (inch-size) ensures optimal mass transfer and longevity.

Customization Potential

The experiment utilized a specific 3.8 cm² circular electrode. 6CCVD specializes in providing custom geometries and integrated contacts essential for complex electrochemical cells.

Custom Dimensions and Geometry: 6CCVD offers custom laser cutting and shaping services to produce BDD electrodes in any required geometry (circular, rectangular, or complex shapes) and size, up to 125 mm.
Integrated Metalization: For robust electrical connections and long-term stability in corrosive EAOP environments, 6CCVD provides internal metalization capabilities (Au, Pt, Pd, Ti, W, Cu) to create custom contacts directly on the BDD surface.
Substrate Engineering: We can tailor the BDD deposition substrate (e.g., Si, Nb, Ta) and film thickness to meet specific conductivity and mechanical stability requirements for high-current density applications like the 20 mA cm^-2 used in this study.

Engineering Support

The successful implementation of this combined electro-Fenton/BDD system relies heavily on precise material selection and process optimization (e.g., managing pH decay, selecting optimal co-catalysts like Cu²⁺).

Application Expertise: 6CCVD’s in-house PhD team specializes in diamond material science and electrochemical applications. We provide consultation on material selection, doping levels, and surface termination necessary to maximize •OH radical generation efficiency for similar pesticide degradation and water remediation projects.
Global Supply Chain: We offer reliable global shipping (DDU default, DDP available) to ensure researchers and engineers worldwide receive high-specification BDD materials promptly.

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

View Original Abstract

Abstract The electro-Fenton process combined with a boron-doped diamond-positive electrode in a one-compartment cell has shown efficient degradation of Cartap (95% in Padan 95SP) by hydroxyl radicals (•OH) generated in the electro-Fenton and the electrochemical oxidation processes. The influence of added NaOCl in a pretreatment step, effects of H 2 O 2 concentration, Fe 2+ -ion addition, presence of further metals acting as co-catalysts, and solution pH on the efficiency of Cartap degradation were studied. The concentration of Cartap was determined by UV-vis spectroscopy according to the 5,5-dithiobis-(2-nitrobenzoic acid) procedure. The efficiency reaches approximately 80% when measured as total carbon concentration decrease, even with increased concentrations of H 2 O 2 , Fe 2+ , or metal ions added as co-catalyst. This limitation is presumably due to recalcitrant intermediates, which cannot be destroyed by •OH.

Tech Support

Original Source

DOI: https://doi.org/10.1007/s10008-020-04581-7