• 关键词：沉积物  表面分形维数(D_s)  分形吸附等温线  FHH方程  热力学模型

• 基金项目：国家自然科学基金资助项目(50178009;20407004);霍英东青年教师基金资助项目(91078)~~

• 王毅力
• 北京林业大学资源与环境学院环境科学学科, 省部共建森林培育与保护教育部重点实验室, 北京 100083

• 芦家娟
• 北京林业大学资源与环境学院环境科学学科, 省部共建森林培育与保护教育部重点实验室, 北京 100083

• 周岩梅
• 1. 北京交通大学土建学院市政与环境工程系, 北京 100044; 2. 中国科学院生态环境研究中心环境水质学国家重点实验室, 北京 100085

• 石宝友
• 中国科学院生态环境研究中心环境水质学国家重点实验室, 北京 100085

• 王东升
• 中国科学院生态环境研究中心环境水质学国家重点实验室, 北京 100085

• 摘要：通过一阶分子连接性指数¹χ与分子表面积TSA之间的相关性计算出吸附分子的尺度,采用分形吸附等温线法计算出妫河沉积物的D_s为2.379,官厅沉积物的D_s为2.836.基于沉积物对N₂的吸附脱附等温线数据,采用FHH(Frenkel-Halsey-Hill)方程计算出两种沉积物的表面分形维数D_s,发现官厅沉积物与妫河沉积物的D_s相差不大;温度影响D_s主要是由于升温改变了沉积物的组成与结构.在本实验中采用热力学模型(thermodynamicmodel)计算出的D_s值大都超过3.此外,沉积物的D_s与其比表面积、矿物含量、CEC、有机质的相关性差.以萘、菲、芘作为码尺计算出的D_s并不完全是表面空间填充能力的客观表现,而是表面吸附过程的一个重要的综合性特征参数.

• Abstract：The surface fractal dimensions (D_s) of two natural sediments were determined by using different models. Fractal Freundlich isotherm equation was used to fit the adsorption data of three polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene and pyrene. Based on the relations of the molecular cross-section areas (a₀), the first molecular connective indexes (¹χ) and the molecular surface areas (TSA) of the three PAHs, the D_s values of 2.836 and 2.379 were obtained for the two sediments from Guanting reservoir and Guihe river, respectively.Based on the nitrogen adsorption-desorption data, the D_s values of the same sediments were also calculated by using FHHand thermodynamic models separately. The results showed that the D_s values of these two sediments had little differences when FHHmodel was applied. The D_s variation of the Guanting reservoir sediments at different temperature could be explained by their composition and structure changes with temperature. And most of D_s values are greater than 3 in this thermodynamic model. Furthermore surface fractal dimension D_s of sediments had weak correlation with the specific surface area (SSA), ion exchange capacity (CEC) and the amount of organic component in particles. It was postulated that the surface fractal dimension D_s of particles calculated by using the three PAHs was an important integrated feature parameter related to the surface adsorption process, rather than a parameter of fully characterizing the space occupation capacity of particle irregular surface.

• Key words：sediments  surface fractal dimensions D_s  fractal adsorption isotherm  FHH equation  thermodynamic model

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