To investigate the effects of nano-TiO2 on the adsorption and desorption of Hg2+ in soil of the drawdown area of the Three Gorges Reservoir

nano-TiO2 particles of different crystal structures (anatase and rutile) were selected

and were added to soil to preparade four concentrations (0

2

4

and 8 g/kg) samples. Meanwhile

Hg2+ solutions with different Hg2+ concentrations were preparade to conduct the Hg2+ adsorption and desorption experiments. The results showed that nano-TiO2 particles increased Hg2+adsorption capacity of soil

but it was affected by the crystal form and concentration of nano-TiO2 particles. The adsorption capacity of anatase particles was stronger than that of rutile particles

and adsorbed Hg2+ was difficult to be desorbed. In anatase particles treatments

when the concentration of nano-TiO2 particles was 4 g/kg

its Hg2+adsorption capacity was the largest

which was 32.65% higher than that of the control group

and its desorption rate was lower than that of the control group. In the treatments with rutile particles

the amount of adsorbed Hg2+ increased with increasing of particle concentration

however Hg2+ was easily desorbed. When the particles concentration was 8 g/kg

its adsorption capacity was the maximum and was 18.18% higher than that of the control group

but its desorption rate was the largest. Nano-TiO2 particles

especially anatase particles

enhance the Hg2+ adsorption capacity of soil

and this may impact the migration and transformation of Hg2+ in the environment.