Enhanced Phosphate Capture by Thermally Modified Calcium Aluminate Decahydrate: Optimization, Performance and...

Area of Science:

• Environmental Chemistry
• Materials Science

Background:

• Eutrophication caused by phosphate pollution necessitates efficient removal technologies.
• Calcium aluminate decahydrate (CAH10) serves as a precursor for developing novel adsorbents.

Purpose of the Study:

• To synthesize and characterize thermally modified calcium aluminate decahydrate (TCAH) as a high-performance phosphate adsorbent.
• To evaluate the adsorption capacity, kinetics, and mechanism of TCAH for phosphate removal.

Main Methods:

• Low-temperature thermal treatment of CAH10 at 120 °C to produce TCAH.
• Batch adsorption experiments to determine adsorption capacity, kinetics, and isotherm models.
• Characterization using SEM-EDS, XRD, FTIR, and XPS to elucidate the adsorption mechanism.

Main Results:

• TCAH demonstrated a maximum phosphate adsorption capacity of 199.80 mg P/g at 25 °C.
• Adsorption followed pseudo-second-order kinetics and Redlich-Peterson isotherms.
• TCAH exhibited high removal efficiency across a wide pH range (3.0-11.0) and selectivity against coexisting anions.
• Phosphate removal involved synergistic amorphous precipitation and inner-sphere complexation.

Conclusions:

• TCAH is a cost-effective and efficient adsorbent for phosphate removal, prepared via low-temperature modification.
• The material shows excellent performance in both synthetic and real wastewater, indicating its potential for eutrophication control.
• TCAH offers a promising solution for phosphate capture and recovery from wastewater.