Incorporation Phytic acid-modified chitosan/sodium alginate melamine sponge composite for highly efficient uranium...

Area of Science:

• Materials Science
• Environmental Chemistry
• Adsorption Science

Background:

• Developing effective adsorbents for uranium removal is crucial for environmental remediation.
• Composite materials offer potential for enhanced adsorption properties but face challenges in fabrication and efficiency.
• Phytic acid modification of biopolymers presents a strategy to improve metal ion binding.

Purpose of the Study:

• To fabricate a novel composite material, phytic acid-modified chitosan/sodium alginate@melamine sponge (PCSS@MS), for uranium adsorption.
• To evaluate the adsorption capacity, efficiency, and reusability of PCSS@MS for uranium (U(VI)) from aqueous solutions.
• To elucidate the adsorption mechanism and identify key functional groups involved in uranium binding.

Main Methods:

• Fabrication of PCSS@MS composite via a cross-linking approach.
• Characterization using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) to confirm structure.
• Adsorption experiments conducted across a broad pH range, varying adsorbent dosage, temperature, and initial uranium concentration.
• Adsorption kinetics and isotherms analyzed using pseudo-second-order and Temkin models.
• Surface chemistry investigated using Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS).

Main Results:

• PCSS@MS exhibited a stable 3D porous architecture.
• Maximum uranium adsorption capacity reached 297.86 mg/g at 318 K.
• Achieved >95% U(VI) removal efficiency under optimal conditions (pH 5, 298.15 K, 80 mg adsorbent).
• Adsorbent maintained 70.8% removal efficiency after four adsorption-desorption cycles.
• Adsorption followed pseudo-second-order kinetics and Temkin isotherm, indicating chemisorption.
• Phosphate groups, along with amino, carboxyl, and hydroxyl groups, were key to U(VI) binding.

Conclusions:

• PCSS@MS is a highly efficient and reusable adsorbent for uranium extraction from aqueous solutions.
• The composite material demonstrates excellent adsorption capacity and stability across various conditions.
• Synergistic interactions of multiple functional groups, particularly phosphate, drive the enhanced uranium adsorption.