Constituting fully integrated colorimetric analysis system for Fe(III) on multifunctional nitrogen-doped...

Area of Science:

• Materials Science
• Analytical Chemistry
• Environmental Science

Background:

• Traditional colorimetric methods for iron(III) determination suffer from interference from colored organic matter and require complex equipment.
• Developing sensitive and selective methods for iron(III) detection in natural water is crucial for environmental monitoring.
• Nanocomposite materials offer potential for integrated analytical systems due to their unique properties.

Purpose of the Study:

• To develop a multifunctional nanocomposite material for the preconcentration, transformation, and colorimetric determination of iron(III).
• To create a solid-phase adsorbent and photocatalyst for efficient iron(III) analysis.
• To establish a simple, visual field detection system for iron(III) in natural water samples.

Main Methods:

• One-step synthesis of nitrogen-doped MoO3 (NMCP) via carbonization of ammonium molybdate and thiourea, fixed onto cellulose filter paper with acrylic resin.
• Utilizing NMCP as a solid-phase adsorbent for Fe(III) preconcentration and as a photocatalyst for humic substance degradation.
• Employing a combination of photoreduction and hydroxylamine treatment for Fe(II) generation, followed by smartphone-based grayscale analysis for colorimetric determination.

Main Results:

• Nitrogen doping enhanced the photodegradation activity of MoO3 by 2.02 times compared to undoped MoO3 and 5.11 times compared to P25-TiO2.
• The NMCP material selectively enriched Fe(III) in the presence of interfering metal ions (Co(II), Cd(II)).
• A visual analysis system based on NMCP achieved a detection limit of 15 μg/L for Fe(III) in the range of 0.05-5 mg/L with R² = 0.976.

Conclusions:

• The developed multifunctional NMCP serves as an effective adsorbent, photocatalyst, and colorimetric sensor for Fe(III) determination.
• The integrated visual analysis system offers a simple, portable, and sensitive method for on-site Fe(III) detection in natural water.
• This approach overcomes the limitations of conventional methods, providing a promising tool for environmental water quality monitoring.