The Influence of the Temperature of Calcination on the Surface Fractal Dimensions of Ca(OH)2-Derived Sorbents

✍ Scribed by A. Venkatraman; L.T. Fan; W.P. Walawender

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 150 KB
• Volume: 182
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0503

✦ Synopsis

Recent investigations have revealed that the surfaces of An investigation was carried out on the surface morphological many materials frequently serving as catalyst supports or features of two types of mesoporous sorbents derived from fine adsorbents exhibit the property of self-similarity over certain hydrated lime powder, termed H-CaO and C-CaO. Specifically, ranges of length scales, and hence, can be described in terms the surface fractal dimensions, d SF 's, of the sorbents obtained at of their surface fractal dimensions, d SF 's (5, 6). The magnivarious temperatures of calcination have been determined from tude of d SF , a relative measure of how well a surface fills their respective adsorption-desorption isotherms of nitrogen meathree-dimensional space, takes on values between 2.0 and sured at 77 K, by a recently proposed thermodynamic method of 3.0, depending on the degree of irregularity. Smooth surfaces analysis. A definite trend in the variation of d SF with the temperaare associated with a value of 2.0, while surfaces that are ture of calcination has been discerned for both sorbents. Moreover, the d SF for each sorbent attained a maximum at 1273 K. The extremely convoluted, i.e., volume-filling, have values apresults of the present work may facilitate our understanding of proaching 3.0 (3, 8, 9). The value of d SF , therefore, offers various phenomena occurring on the irregular interfaces of heteroa scale-independent, quantitative measure for the degree of geneous systems at elevated temperatures.