Magnetically separable Co_0.6Fe_2.4O₄/MIL-101-NH₂ adsorbent for Congo red efficient removal

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Developing efficient adsorbents for pollutant removal is crucial.
• Magnetic composites offer advantages in separation and reusability.
• Metal-organic frameworks (MOFs) show potential in adsorption applications.

Purpose of the Study:

• To synthesize and characterize a novel magnetically separable composite, Co0.6Fe2.4O4/MIL-101-NH2.
• To evaluate the adsorbent's efficiency for Congo red (CR) removal from aqueous solutions.
• To investigate the adsorption mechanisms and influencing parameters.

Main Methods:

• In-situ growth of MIL-101-NH2 on magnetic nanoparticles (Co0.6Fe2.4O4).
• Systematic study of adsorption parameters: adsorbent dosage, pH, time, temperature, and interfering ions.
• Kinetic, isotherm, and thermodynamic analyses of CR adsorption.
• Evaluation of adsorbent reusability and selectivity for CR over other dyes.

Main Results:

• The composite exhibited a high BET surface area and rapid magnetic separation (<30 s).
• CR adsorption followed pseudo-second-order kinetics and Langmuir isotherm models.
• Maximum adsorption capacity reached 1756.19 mg/g at 298.15 K.
• Adsorbent retained 78% capacity after 5 cycles.
• Adsorption mechanisms involved π-π interactions, electrostatic forces, hydrogen bonding, and metal coordination.

Conclusions:

• The Co0.6Fe2.4O4/MIL-101-NH2 composite is a highly effective adsorbent for CR removal.
• The adsorbent demonstrates excellent capacity, selectivity, and reusability.
• This MOF-based magnetic composite shows significant potential for water treatment and environmental remediation.