In this work, the effect of various environmental factors on U(VI) sorption to illite was investigated,such as pH, ionic strength, humic acid (HA) and temperature. U(VI) sorption to illite strongly depended on pH values, ionic strength and temperature. At pH < 6.0, the presence of HA obviously improved U(VI) sorption on illite, because of the strong complexation between HA and U(VI) on illite surface. However, a slight inhibiting effect appeared at pH > 6.0. The thermodynamic parameters (Delta HA degrees, Delta SA degrees and Delta GA degrees) calculated from the temperature dependent sorption...