Rare Earth Element Adsorption from Water Using Alkali-Activated Waste Fly Ash

Area of Science:

• Environmental Chemistry
• Materials Science
• Waste Management

Background:

• Increasing demand for rare earth elements (REEs) due to new technologies.
• Limited awareness of the environmental and health impacts of REEs.
• Need for effective methods for REE removal from water.

Purpose of the Study:

• To synthesize inorganic aluminosilicate polymers from waste fly ash.
• To investigate the application of these polymers for removing selected REEs (Gd3+, Y3+, Sc3+) from water.
• To explore the potential of modified ash in waste reduction and construction applications.

Main Methods:

• Alkaline activation of waste fly ash to synthesize aluminosilicate polymers.
• Characterization of modified materials using XRD and DRIFT spectroscopy.
• Investigation of REE adsorption using thermodynamic and kinetic parameters.

Main Results:

• Successful synthesis of aluminosilicate polymers with a distinct polymeric network structure.
• Observation of calcite formation, indicating the presence of wood ash.
• High adsorption efficiencies (up to 95%) for Gd3+, Y3+, and Sc3+ in single and mixed solutions.
• Presumed adsorption mechanism involving chemisorption and ion exchange.

Conclusions:

• Alkali-activated fly ash and wood ash mixtures are effective adsorbents for REE removal.
• The study contributes to understanding REE environmental remediation and waste valorization.
• Modified ash shows potential for use as construction additives.