Fe(III) cross-linked cellulose-agar hydrogel beads for efficient phosphate removal from aqueous solutions

Area of Science:

• Materials Science
• Environmental Chemistry
• Water Treatment

Background:

• Phosphate pollution is a significant environmental concern, leading to eutrophication in aquatic ecosystems.
• Effective and sustainable methods for phosphate removal from wastewater are crucial.

Purpose of the Study:

• To synthesize and characterize Fe(III) cross-linked cellulose agar beads (Fe-CLCAB) for phosphate ion adsorption.
• To investigate the adsorption capacity, kinetics, and desorption efficiency of Fe-CLCAB.

Main Methods:

• Sol-gel synthesis of Fe-CLCAB.
• Characterization using FTIR, SEM, and UV-Vis spectroscopy.
• Batch adsorption studies to determine optimal conditions and kinetic/isotherm models.
• Cyclic adsorption-desorption tests.

Main Results:

• Fe-CLCAB demonstrated high phosphate adsorption efficiency (94%) at pH 5.
• The maximum adsorption capacity was 73.13 mg/g, fitting Langmuir and Freundlich isotherms.
• A two-step elution with NaCl enabled complete phosphate desorption.
• Regenerated beads retained 42% efficiency after six cycles, indicating good reusability.

Conclusions:

• Fe-CLCAB is a stable and effective adsorbent for phosphate removal.
• Ion exchange is the primary mechanism for phosphate adsorption and desorption.
• The developed hydrogel beads show promise for practical water treatment applications.