Fig. 1. XRD pattern of surrounding rock and SRM colloid in the repository (color online)

Fig. 2. FT-IR spectra of surrounding rock and SRM colloid in the repository (color online)

Fig. 3. SEM images of surrounding rock powder (a, b) and SRM colloid (c, d)

Fig. 4. Variations of Cs⁺ adsorption capacity by SRM colloid and K_d with contact time (T=293 K, C₀=10 mg·L^-1, pH=7)

Fig. 5. (a) Change of Zeta potential and particle size of SRM colloid with temperature, (b) Curves of Cs⁺ adsorption capacity by SRM colloid and K_d changing with temperature (t=720 min, C₀=10 mg·L^-1, pH=7)

Fig. 6. Isotherm fitting curves of Cs⁺ adsorption capacity by SRM colloid (t=720 min, T=293 K, pH=7) (color online)

Fig. 7. Changes of Zeta potential and particle size of SRM colloid with pH value (a), curves of Cs⁺ adsorption capacity by SRM colloid and K_d changing with pH value (b) (t=720 min, T=293 K, C₀=10 mg·L^-1)

Fig. 8. Effects of co-existing ions on Zeta potential (a) and particle size of SRM colloid (b) (t=720 min, T=293 K, C₀=10 mg·L^-1, pH=7)

Fig. 9. Effect of coexisting cations on Cs⁺ adsorption by SRM colloid (t=720 min, T=293 K, C₀=10 mg·L^-1, pH=7) (color online)