Adsorptive Removal of Iron Using SiO₂ Nanoparticles Extracted from Rice Husk Ash

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Silica (SiO2) nanoparticles offer potential for environmental remediation.
• Rice husk ash (RHA) is a sustainable source of silica.
• Iron (Fe2+) contamination in water requires effective removal methods.

Purpose of the Study:

• To synthesize SiO2 nanoparticles from RHA using the sol-gel method.
• To investigate the adsorption capacity of SiO2 nanoparticles for Fe2+ ions.
• To determine optimal conditions for Fe2+ removal using synthesized SiO2.

Main Methods:

• Sodium silicate extraction from RHA followed by sol-gel synthesis of SiO2 nanoparticles.
• Morphological and chemical characterization of SiO2 nanoparticles (surface area, pore size).
• Batch adsorption experiments to study the effect of pH, contact time, and adsorbent dose on Fe2+ removal.

Main Results:

• SiO2 nanoparticles exhibited a surface area of 78 m²/g and uniform pores (2.71 nm).
• Optimal adsorption conditions were identified as pH 5, 20 min contact time, and 0.5 g adsorbent dose.
• The synthesized SiO2 demonstrated a loading adsorption capacity of 9 mg Fe2+/g SiO2 in the concentration range of 0.1-1.0 mg/L.

Conclusions:

• SiO2 nanoparticles derived from RHA are effective adsorbents for Fe2+ removal from aqueous solutions.
• The synthesized nanoparticles show promise for water treatment applications.
• Modified SiO2 nanoparticles could be utilized for heavy metal removal and drug delivery.