Adsorption of uranium from aqueous solution using chitosan-tripolyphosphate (CTPP) beads

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Uranium contamination in water poses significant environmental and health risks.
• Developing efficient and cost-effective adsorbents for uranium removal is crucial.

Purpose of the Study:

• To synthesize and characterize chitosan-tripolyphosphate (CTPP) beads for uranium adsorption.
• To investigate the factors influencing uranium adsorption and determine the adsorption mechanism.

Main Methods:

• CTPP beads were prepared using an in-liquid curing method with varying cross-linking densities.
• Fourier-transform infrared (FTIR) spectroscopy was used for characterization.
• Batch adsorption experiments were conducted to study the effects of pH, contact time, and initial concentration.
• Adsorption isotherms (Langmuir, Freundlich) and kinetic models (pseudo-first order, pseudo-second order, intraparticle diffusion) were applied.

Main Results:

• Higher cross-linking density of CTPP beads led to improved uranium adsorption capacity.
• The maximum adsorption capacity was estimated to be 236.9 mg/g based on the Langmuir model.
• Adsorption followed pseudo-second order kinetics, indicating chemisorption.
• FTIR analysis suggested that phosphate groups are primarily responsible for uranium adsorption.

Conclusions:

• CTPP beads are a promising adsorbent for uranium removal from aqueous solutions.
• The adsorption process is influenced by cross-linking density, pH, contact time, and initial uranium concentration.
• Phosphate groups within the CTPP structure are key functional groups for uranium binding.