Effect of Kaolin particle size on the removal of Pb(II) from aqueous solutions by Kaolin-supported nanoscale zero-valent iron

Abstract

The removal of Pb(II) from aqueous solutions was investigated using kaolin with two different particle sizes (2.3 and 45 μ m) with and without nanoscale zero-valent iron (nZVI, at a Fe content close to 30%). The experimental results show that 2.3 μ m kaolin loaded with nZVI (K-nZVI) had the best Pb(II) removal performance under various test conditions. After 24 h, it removed 99.5% of Pb(II) ions in the solution, followed by 45 μ m K-nZVI, 2.3 μ m kaolin, and 45 μ m kaolin (89.01%, 68.8%, and 65.8%, respectively). The removal rates by all four kaolin samples increased with increasing pH in the range of 2–6, and with increasing temperature between 30 °C–60 °C. The results show that using finer carrier particles improves the performance of K-nZVI for removing Pb(II) in aqueous solutions.

Keywords

• particle size
• Kaolin
• zero-valent iron
• adsorptive removal