【作者】 于富玲；

【导师】 解明曙； 王毅力；

【作者基本信息】 北京林业大学 ， 生态学， 2005， 硕士

【摘要】 本文研究了颗粒活性炭吸附染料的特征,测定了6种染料的吸附等温线,并探讨了pH值、离子强度、温度、振荡强度和颗粒活性炭用量等因素对吸附的影响。结果表明,pH值、离子强度、振荡强度和颗粒活性炭用量均是影响吸附的主要因素,温度升高使吸附量增加,并且存在固体浓度效应。它们的吸附等温线均符合Frendlich方程。运用Langmuir分形吸附等温线方程模拟了颗粒活性炭对染料的吸附,得到了较好的效果,并且以染料分子作为码尺计算出颗粒活性炭的表面分形维数Ds为2.5902。 对吸附动力学数据的模拟表明,不同温度下6种染料在颗粒活性炭表面的吸附过程符合非线性动力学。吸附速率一般随着温度的升高而增加,反应活化能在0.20～1.75 kJ.mol^-1之间。吸附动力学过程分为快速吸附和慢吸附两个阶段,溶液中剩余的染料浓度变化动力学符合方程:C_out ∝ t^α,表明该过程具有类分形动力学特征,并由指数α计算颗粒活性炭的表面分形维数Ds。 建立了复杂分子吸附反应时指数h与分形子谱维数d_s、分形介质的表面分形维数Ds的关系式。进一步分析表明,吸附反应的逐时速率系数k与反应时间t呈指数关系;相应的分形子谱维数d_s<2。随着染料的初始浓度的增加,d_s也随之增加,而h和k₀值通常会随之降低。更多还原

【Abstract】 In this paper the adsorption properties of six dye compounds onto granular activated charcoal were studied. The results showed that the influences of pH, ion strength , temperature, shake strength and the amount of granular activated charcoal were important for adsorption, the amount absorbed increased with increase of temperature, and actually the solid concentration effect was oberseved in adsorption process. The adsorption of the six dye compounds exhibited Freundlich adsorption behavior. The Langmuir fractal adsorption equation was used to model the adsorption isotherm data between granular activated charcoal and six kinds of dye compounds, and the relative coefficients exceed 90%. Based on that modeling results the calculated surface fractal dimension Ds of granular activated charcoal is 2.5902.The adsorption dynamic processes of six dye compounds onto granular activated charcoal were studied in this paper. Results showed that the adsorption behaviors of these compounds followed experiential non-linear kinetic equations, and higher adsorption rate was observed at higher temperature generally. The calculated apparent activated energy （Ed） values were within the range of 0. 20^l. 75 kJ.mol^-1, demonstrating the adsorption processes were relatively fast. The adsorption dynamic process was divided into a fast adsorption step and a slow one. The residual dye concentration in solution varied with adsorption time according to the following relation: c_out ∝t^-α, showing that the adsorption dynamic process was a fractal-like one, and the surface fractal dimension Ds could be determined through the equation: α =1/（1-1/n）.To elucidate the adsorption kinetics of complex molecules onto fractal surfaces, the relations of reaction exponent h with both fractal spectrum dimension d_s and surface fractal dimension Ds were developed. Further analysis indicated that the adsorption kinetic processes have fractal-like characteristics. The stepwise rate coefficient （k） has a power-law relation with reaction time （t）, and the corresponding spectral dimensions d_s are less than two. It was also noted that increasing the initial concentrations of dye compounds led to increases of d_s values, but decreases of the h and k₀ values.更多还原