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Electrochemical (EC) and photoelectrochemical (PEC) water treatment systems are gaining popularity, necessitating new electrode materials that offer reliable performance across diverse application platforms. For applications specifically targeting dilute chemical pollutants ( i.e. , parts-per-million concentrations or less), beneficial electrode properties include high surface area to overcome kinetic overpotential losses, low electrode areal electrical resistance, and high water permeability with sufficient mechanical strength for use in electroactive membrane-based treatment systems. Here, we used electrospinning to fabricate (photo)electrodes from carbon nanofibers (CNFs) containing titanium dioxide (TiO 2 ) nanoparticles. Optimal CNF/TiO 2 composites were electrochemically and photochemically active with a surface area of ∼50 m 2 g −1 and electrode areal resistance of 2.66 Ω cm 2 , values comparable to commercial carbon-based electrode materials ( e.g. , Kynol Activated Carbon Cloth). Transformation experiments with carbamazepine (CBZ), a recalcitrant organic contaminant, suggest CNF/TiO 2 electrodes function dually as sorbents, first binding CBZ prior to oxidation at positive applied potentials. Complete CBZ transformation was observed in both EC (dark) and PEC (UV light; 280 mW cm −2 ) systems over 90 minutes, with PEC systems exhibiting 1.5-fold higher transformation rates ( k obs ∼ 0.18 min −1 ) at +1.00 V ( vs. Ag/AgCl). Composite electrodes also exhibited stability across repeated use, yielding consistent current densities over five experimental cycles (120 min each) of CBZ transformation (0.25 ± 0.03 mA cm −2 ). Because of their high surface area, electrical conductivity, photoactivity, and electrochemical stability, these electrospun CNF/TiO 2 composites represent promising (photo)electrode alternatives for diverse EC and PEC applications.
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This content will become publicly available on December 1, 2025
Detection of Diclofenac and Carbamazepine using Voltammetry and Flow Injection Analysis at Boron‐Doped Diamond Thin‐Film Electrodes
Abstract The electrochemical detection of two pharmaceuticals, diclofenac (DCF) and carbamazepine (CBZ), was investigated as an oxidation current using boron‐doped nanocrystalline diamond (BDD) thin‐film electrodes. Both voltammetry and flow injection analysis with amperometric detection (FIA‐EC) were used to measure the drugs in standard solutions and a urine simulant. The oxidation potential for DCF wasca. 0.7 V vs. Ag/AgCl (3 M KCl) in 0.1 M phosphate buffer (pH 7.2) and wasca. 1.2 V for CBZ in 0.1 M perchloric acid. The DCF oxidation reaction was diffusion controlled at the detection potential with evidence of some surface fouling by reaction products. The CBZ oxidation reaction was also controlled by diffusion at the detection potential, but with no surface fouling. The voltammetric peak currents for both drugs increased linearly with the concentration in the micromolar range (r2≥0.994). FIA‐EC analysis of DCF and CBZ revealed a linear dynamic range from at least 0.1 to 100 μM with the actual minimum concentration detectable (S/N=3) being less than the lowest concentration measured. The recovery percentage for DCF in the urine simulant ranged from 94–108% and from 97–100% for CBZ, both assessed using square wave voltammetry. FIA‐EC data revealed that the BDD electrodes offer excellent intra and inter‐electrode repeatability with an RSD for DCF and CBZ of 4.90% and 3.81%, respectively. The BDD electrode provided good reproducibility and response stability over eight days of continuous use detecting both DCF and CBZ. Overall, BDD electrodes are a viable material for the sensitive, selective, and reproducible electrochemical detection of these two pharmaceuticals.
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- Award ID(s):
- 2150173
- PAR ID:
- 10611645
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Electroanalysis
- Volume:
- 36
- Issue:
- 12
- ISSN:
- 1040-0397
- Subject(s) / Keyword(s):
- diamond electrodes, pharmaceutical detection, electrochemical methods, flow injection analysis
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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