Control of Al2O3/TiO2 sorbent synthesis parameters to enhance fluoride remediation of impaired water resources
Year: 2025
Type: article
Abstract: Alumina is widely used for fluoride ion removal due to its high affinity but is limited by low uptake capacity and structural instability. To overcome these issues, innovative alumina-titania sorbents were developed using co-precipitation. These sorbents maintained a surface area of ∼260 m 2 /g and pore volume of ∼0.21 cm 3 /g regardless of feed flow rate. However, low NaOH molarity significantly increased surface area, peaking at 343 m 2 /g with 1 M NaOH. Aging also enhanced surface area, reaching ∼315 m 2 /g. Equilibrium isotherms showed that a feed flow rate of 25 mL/min achieved the highest fluoride uptake (0.19 meq/g). NaOH concentrations ≤4 M produced favourable isotherm profiles, while ≥4 M resulted in unfavourable outcomes. Aging the synthesis mixture for 1–2 h was optimal, as extended aging reduced isotherm performance. The Al 2 O 3 /TiO 2 sorbents also removed calcium, magnesium, barium, strontium, potassium, and silica from groundwater. Optimal synthesis conditions were identified as a 25 mL/min feed flow rate, 2 M NaOH concentration, and a 2-h aging time. The sorption mechanism combined electrostatic attraction and ligand exchange, highlighting the potential of these materials for multifunctional water treatment. • Fluoride uptake increased by controlling synthesis parameters. • Aging promoted sorbent surface areas up to ca. 315 m 2 /g. • NaOH molarity ≤4 M resulted in favourable equilibrium isotherm profiles. • Sorption via a combination of electrostatic attraction and ligand exchange. • Silicates are also removed from solution by the alumina/titania materials.
Institution: Queensland University of Technology
Language: English
Topic: Fluoride Effects and Removal
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,640
OpenAlex ID: W4414217303