Development of porosity in brown-coal chars on activation with carbon dioxide

✍ Scribed by Jerzy Berger; Teresa Siemieniewska; Kazimierz Tomków

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 765 KB
• Volume: 55
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(76)90063-6

✦ Synopsis

Two petrographic types of Tertiary brown coals, xylitic and earthy, were carbonized, and activated with carbon dioxide between 1123 and 1273 K. The development of porosity in the activated chars was studied by adsorption of benzene and carbon dioxide at 298 K and by mercury porosimetry.

The type of brown coal exerts a dominant influence on the properties of the activated chars. The xylitic brown-coal, when compared with the earthy brown-coal, yields products with a higher pore volume and better sorptive properties. Activated chars from the xylitic brown-coal reach a surface area of 800 m* g-t, contained principally in micropores and very narrow mesopores (radius below 3.0 nm). Dimensions of pores in the activated chars from the earthy brown-coal are less uniform, the mesopores are broader (an important part of them has a radius between 5.0 and 100.0 nm), and micropores are present to a smaller extent; the surface area of these products is between 200 and 350 m* g-l.

Activated chars from both types of brown coals have a well developed system of macropores.