Sodium Alginate/UiO-66-NH₂ Nanocomposite for Phosphate Removal

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Phosphorus pollution is a growing environmental concern, driving the need for efficient phosphate removal from water to combat eutrophication.
• Modified metal-organic framework (MOF) materials, specifically UiO-66-NH2, show potential as adsorbents due to their structural properties.
• Alginate-based composites offer a promising matrix for developing advanced adsorbent materials.

Purpose of the Study:

• To synthesize and characterize a novel alginate/UiO-66-NH2 composite hydrogel modified with polyethyleneimine (UiO-66-NH2/SA@PEI).
• To evaluate the phosphate adsorption performance of the UiO-66-NH2/SA@PEI composite under various conditions.
• To assess the reusability and stability of the developed adsorbent material for wastewater treatment.

Main Methods:

• Preparation of millimeter-sized alginate/UiO-66-NH2 composite hydrogel modified by polyethyleneimine (UiO-66-NH2/SA@PEI).
• Characterization of the composite material using SEM, FTIR, XRD, and BET techniques.
• Conducting static, dynamic, and cyclic adsorption experiments to determine optimal adsorption conditions (pH, temperature, dosage, concentration) and assess performance.

Main Results:

• The UiO-66-NH2/SA@PEI composite exhibited excellent phosphate adsorption capacity, reaching 68.75 mg/g under optimal conditions (65 °C, pH = 2).
• The adsorbent demonstrated high efficiency, maintaining a 99% adsorption rate even after five adsorption-desorption cycles.
• Characterization confirmed the successful integration of UiO-66-NH2 within the alginate matrix and modification by PEI, enhancing separation and adsorption properties.

Conclusions:

• The UiO-66-NH2/SA@PEI composite hydrogel is a highly effective and stable adsorbent for phosphate removal from aqueous environments.
• The material's design facilitates easy separation and demonstrates robust performance, making it suitable for practical wastewater treatment applications.
• This study highlights the potential of modified MOF-based composite hydrogels in addressing environmental phosphorus pollution.