ADSORPTION EQUILIBRIUM AND KINETIC OF DYES ONTO DRIED ACTIVATED SLUDGE
CHEN Chun yun 1, ZHUANG Yuan yi 1,LIU Fei 1,YANG Min 2 (1 Department of Environmental Science, Nankai University, Tianjin 300071,China; 2 Research Center for Eco Environmental Sciences, Chinese Academy of Sciences, Beijing 100085,China)
The present paper aims at testing the kinetic adsorption of dyes on dried activated sludge and their equilibrium on the purpose to find the possible applications of such adsorption in treating dye containing sewage. The author has chosen dye reactive light yellow KD 3G, the direct dark brown M and acid mordant brown RH for representative adsorbates, the adsorbents been prepared by wet removing in the room temperature from the activated sludge and then drying the sludge at 60 ℃. Our experiments are conducted in a flask shaking system in which dyes are absorbed by the sludge. The experiments indicate that the adsorption isotherms of all of the tested dyes fit the Freundlich equation respectively, and that the adsorption isotherm of the dye acid mordant brown RH followed Langmuir equation too. Furthermore, the uptake process of the dyes has proven to follow the second order kinetic model, and can be described by the first order Lagergren equation. The first order absorption rate constants, k 1, in temperature 15 ℃, 20 ℃, 25 ℃, 35 ℃, 45 ℃ for the tested dyes were in the range of direct dark brown M 0.015～0.040 min -1 , with the reactive light yellow KD 3G 0.002～0.003 2 min -1 and acid mordant brown RH 0.007～0.012 min -1 respectively. The second order constants of adsorption, k 2, were in the range of dye reactive light yellow KD 3G 0.000 27～0.000 47 g/(mg·min), direct dark brown M 0.006 5～0.029 g/(mg·min) and acid mordant brown RH 0.003～0.013 2 g/(mg·min) respectively. The errors between qe values calculated from the second order adsorption kinetic model and the experimental qe values are below 7% in the adsorption temperature range mentioned above, which helps to show the applicability of this model for the prediction of equilibrium absorption capacity. The absorption equilibrium capacities qe in the experimental dye concentration of 50 mg/g were in the range of direct dark brown M 14.3～16.0 mg/g, acid mordant brown RH 7.2～9.6 mg/g, reactive light yellow KD 3G 16.5～19.2 mg/g respectively. The absorption rates of studied dyes on dried sludge varied with dye solution temperatures.
【Fund】： 国家自然科学基金项目 (编号 :2 98770 1 4 );; 博士点基金 (编号 :0 0 0 0 551 9);; 环境水化学国家重点实验室开放基金 (编号 :2 0 0 0 2 )
【CateGory Index】： X703
【CateGory Index】： X703