【摘要】 采用图象法、染料吸附和N2吸附-脱附实验分别确定颗粒活性炭的表面分形维数,探讨不同尺度下颗粒活性炭的表面分形特征,为描述环境污染物在颗粒活性炭介质微界面上的传质、反应的非线性规律提供支撑。结果表明,颗粒活性炭的表面从分子尺度(几个A)到微观尺度(几个微米)之间一般都具有多分形特征,且不同尺度范围内的表面分形维数差异较大．在研究尺度的范围内．图象分辨率的增大,相应的Ds一般呈变小的趋势,但图象法确定的纳米尺度下的Ds值远小于吸附法确定的A尺度下的Ds值。SEM图象计算出的Ds为2．04-2．39,AFM图象计算出的Ds为2．00-2．43。N2吸附-脱附法确定颗粒活性炭孔表面分形维数Ds为2．97以上,比分形吸附等温线确定的外表面和部分孔表面综合的表面分形维数值Ds=2．59高出许多。另外,图象法确定的表面分形特征的尺度变化范围约为100-102量级之间,确定的表面分形维数是纯粹几何意义上的表面粗糙特征的描述,可能需要多角度的大量代表性图片来综合分析;而吸附法是描述颗粒特定尺度下整个表面的粗糙程度。它们在同一尺度下的分形维数值是否相关或相等,依然是需要我们进一步的探讨。更多还原

【Abstract】 The surface fractal properties and surface fractal dimensions of granular activated charcoal on different scales were studied by image-method, dye adsorption-method and N2 adsorption-desorption-method, which could provide some proofs on the non-linear law about pollutants mass-transfer and reaction on the micro-interface between granular activated charcoal and environmental medium. In general, the multifractal properties of granular activated charcoal surface existed from molecule scale (A) to micro-scale (μm), and much difference had been found in surface fractal dimensions(Ds) among different scale ranges. In the range of images, the surface fractal dimensions(Ds) calculated from the.images decreased with the increase of their resolution, but the surface fractal dimensions (Ds) of nano-scale by image methods were much less than ones of molecule scale(A) by adsorption methods. The Ds values of SEM images were 2. 04 - 2. 39, and those of AFM images were 2. 00 - 2. 43. The pore surface fractal dimensions (Ds) of granular activated charcoal by N2 adsorption-desorption method were more than 2. 97, and much higher than the Ds value of 2. 59 by fractal adsorption isotherm method, which depicted the average roughness of exterior surface and part pore surface of granular activated charcoal. The scale range for surface fractal dimensions was 100 - 102 by images method, which determined the surface rugosity on the pure geometry meaning, and should be comprehensively analyzed from many symbolic images, especially for the surface with multifractal properties. For absorption method, the molecular yardstick could contact total particle surface in special scale. It should be further discussed that the relations between the surface fractal dimensions (Ds) from this two methods.更多还原