High-Efficiency Capture of Indole-3-Acetic Acid (IAA) from Water Using AgNPs-Decorated Silicate-Based Nanocomposites

Area of Science:

• Environmental Science
• Materials Science
• Nanotechnology

Background:

• The widespread use of indole-3-acetic acid (IAA), a plant hormone, in agriculture has resulted in its presence as a water contaminant.
• Efficient technologies are required for the removal of IAA from water sources.

Purpose of the Study:

• To synthesize and characterize novel nanocomposites for enhanced adsorption of IAA.
• To investigate the adsorption mechanism and performance of these materials for environmental remediation.

Main Methods:

• Synthesis of halloysite (Hal), bentonite (Ben), sepiolite (Sep), and diatomaceous earth (DE) functionalized with silver nanoparticles (AgNPs).
• Characterization using XRD, SEM-EDS, HPLC, DLS, and Zeta Potential measurements.
• Kinetic and thermodynamic modeling of IAA adsorption.

Main Results:

• All functionalized nanocomposites showed significantly higher IAA adsorption capacity compared to pristine materials.
• Adsorption followed a biphasic pathway with rapid initial sequestration and diffusion-limited equilibration.
• A surface-confined ligand exchange mechanism involving IAA coordination around AgNPs was identified.

Conclusions:

• Engineered AgNPs@silicate platforms demonstrate high efficiency for removing IAA, a common phytohormone contaminant.
• Material performance is linked to the accessibility of silicate frameworks, not solely surface area.
• These nanocomposites represent sustainable and effective materials for environmental remediation.