Abstract: In this study, β-FeOOH-Mt was prepared by montmorillonite modified with beta hdroxy iron oxide. N₂TPD was used to identify the structure of β-FeOOH-Mt. The adsorption of copper ions in acidic mine drainage by β-FeOOH-Mt (3.5) was examined. It was found that the specific surface area and the pore volume of montmorillonite increased after modification. β-FeOOH-Mt (3.5) had strong adsorption capacity for Cu²⁺. When the initial concentration of Cu²⁺ was 5-25 mg·L^-1, the application amount of β-FeOOH-Mt (3.5) was 2-9 g·L^-1, and the concentration of Cu²⁺ was lower than 0.5 mg·L^-1 after 20 min. The Langmuir isotherm model better fitted with the experimental data than Freundlich isotherm model. The adsorption process is in accordance with the single molecule adsorption model. The kinetic study showed that the adsorption followed the quasi second adsorption kinetic equation with a good correlation.

Key words: soil water movement, hydrogen and oxygen stable isotopes, loess area, land use change