Mercury Ion Selective Adsorption from Aqueous Solution Using Amino-Functionalized Magnetic Fe₂O₃/SiO₂ Nanocomposite

Area of Science:

• Materials Science
• Environmental Science
• Nanotechnology

Background:

• Mercury (Hg2+) contamination in water poses significant environmental and health risks.
• Developing efficient and cost-effective methods for mercury removal is crucial for environmental remediation.
• Magnetic nanocomposites offer advantages in separation and recovery processes.

Purpose of the Study:

• To synthesize and characterize amino-functionalized magnetic Fe2O3/SiO2 nanocomposites.
• To evaluate the efficiency of these nanocomposites in removing Hg2+ ions from aqueous solutions.
• To investigate the adsorption mechanism, kinetics, and thermodynamics of Hg2+ removal.

Main Methods:

• Synthesis of Fe2O3/SiO2-NH2 nanocomposites with varying silicate ratios.
• Characterization using FT-IR, XRD, SEM, BET, TGA, zeta-potential, and particle size analysis.
• Adsorption experiments to determine optimal pH, dosage, and contact time, followed by kinetic, isotherm, and thermodynamic studies.

Main Results:

• The Fe2O3/SiO2-NH2 adsorbent with a 1:2 silicate ratio showed the highest adsorption capacity (152.03 mg g-1) due to a large surface area (100.1 m2 g-1).
• Adsorption followed pseudo-second-order kinetics and the Langmuir model, indicating chemisorption and monolayer formation.
• The process was spontaneous, endothermic, and selective for mercury ions, with easy magnetic recovery and regeneration.

Conclusions:

• Amino-functionalized Fe2O3/SiO2 magnetic nanocomposites are highly effective for Hg2+ removal.
• The magnetic properties facilitate easy separation and reuse, making them suitable for wastewater treatment.
• These nanomaterials present a sustainable and efficient solution for mercury remediation.