Removal of aqueous toxic Hg(II) by synthesized TiO sub(2) nanoparticles and TiO sub(2)/montmorillonite

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2011-01, Vol.166 (2), p.631-638
• Main Authors: Dou, Binlin, Dupont, Valerie, Pan, Weiguo, Chen, Bingbing
• Format: Article
• Language: English
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2010.11.035

The adsorption and photocatalytic reduction of toxic Hg(II) in aqueous solutions were investigated at different temperatures using synthesized TiO sub(2) nanoparticles and TiO sub(2)/montmorillonite. The synthesized materials were tested by TGA, BET, TEM and XRD methods. High-purity anatase TiO sub(2) nanoparticles with an average diameter of 9.10 nm were produced by the acid catalyzed sol-gel method at 500 degree C, and the specific surface area of synthesized TiO sub(2) nanoparticles was in excess of 200 m super(2) g super(-1). TiO sub(2)/montmorillonite was prepared by slurry reactions, resulting in average pore size of 3.10 nm with TiO sub(2) nanoparticles on the montmorillonite surface. TiO sub(2)/montmorillonite with a 22 wt% TiO sub(2) load exhibited a specific surface area of 239 m super(2) g super(-1). Removal of Hg(II) in aqueous solutions at 25, 35 and 45 degree C in darkness and under UV illumination showed that the photocatalytic reduction of Hg(II) increased with increasing temperature, and a decline in adsorption was observed for a rise in temperature from 25 to 45 degree C, following the exothermicity of the adsorption process. The adsorption behavior of Hg(II) on TiO sub(2) nanoparticles was well described by the Langmuir isotherm model, and the rates were simulated by the Elovich equation. A first-order reaction model was used to simulate the photocatalytic reduction reaction of Hg(II) in aqueous solutions, and a good fit was obtained with the experimental data.