The impact of temperature (298 K, 313 K, and 333 K) on the sorption of selenium(VI) onto anatase was investigated for the first time. At a macroscopic level, batch experiments showed a decrease of selenium(VI) retention with both increasing pH (3.5-7.0) and temperature. The thermodynamic parameters of the sorption reaction, i.e. the enthalpy Delta H-R, entropy Delta S-R, and the Gibbs free energy Delta(R)G, were determined from the temperature dependence sorption data using the van't Hoff equation. The sorption process was found to be exothermic. Neither significant phase transformation nor a significant increase of anatase solubility could be detected with increasing temperature by XRD and ICP-MS. However, electrophoretic mobility measurements showed that both the zeta potential as well as the isoelectric point (pH(IEP)) of anatase were shifted to lower values with increasing temperature, leading to a decreased selenium(VI) sorption. At a microscopic level, the sorption mechanism of selenium(VI) onto anatase was elucidated at the three investigated temperatures by means of in situ Attenuated Total Reflection Fourier-Transform Infrared spectroscopy (AIR FT-IR). Results evidenced the formation of outer-sphere surface complexes, with no significant structural changes within the investigated temperature range. (C) 2012 Elsevier Inc. All rights reserved.