关键词:

活性炭, 六价铬, 超声波, 吸附, 脱附

Abstract:

Effects of ultrasound on the adsorption and desorption of chromium (Ⅵ) on activated carbon were studied. Results showed that within the range of experiment concerned, the adsorption ratio of chromium(Ⅵ) decreases with pH increasing regardless ultrasound application. However, with ultrasound, the equilibrium of the system moves to the direction in the decrease of adsorption, which becomes severe with the increase in pH. With ultrasound, as the initial Cr(Ⅵ) concentration increases from 20 mg·L^-1 to 110 mg·L^-1, the removal efficiency of Cr(Ⅵ) drops from 99.9% to 79.8%, while the equilibrium adsorption capacity increases from 3. 3 mg·g^-1 to 15. 0 mg·g^-1, which is similar to that without ultrasound. The adsorption ratio continuously increases until to an equilibrium without ultrasound,while, it appears a slight decrease after being quickly to the equilibrium, and then gradually increases to the equilibrium again in case with ultrasound. The desorption ratio of Cr(Ⅵ) is very small in distilled water regardless ultrasound application. While, the desorption can be greatly improved by the addition of NaOH, and this promotion effect is remarkable for the ultrasonic system.

Key words:

活性炭, 六价铬, 超声波, 吸附, 脱附