| Autor: |
Nohman, A.K.H., Zaki, M.I. |
| Zdroj: |
Adsorption Science & Technology; March 1994, Vol. 11 Issue: 1 p1-14, 14p |
| Abstrakt: |
Nitrogen sorption isotherms have been determined at 77 K on pre-characterised MnOxbulk samples obtained by calcination at 423–873 K of K+-contaminated NH4MnO4. The isotherms have been analysed for estimating the surface area and pore structure of the test samples adopting the αs-method and standard adsorption data determined on a local reference material (calcination product of the permanganate at 1273 K for 20 h). The most prominent result of the present investigation is that the presence of K+leads to the formation of a channel-structured KMn8O16bulk phase at 573 K and the following consequent textural modifications: (i) a considerable increase in the surface area to 205 m2/g, (ii) the construction of a uniform pore system consisting of slit-shaped pores with narrow entrances, and (iii) the evolution of energetically uniform internal surfaces of considerable area (= 92 m2/g). The results also reveal that the test surfaces generally exhibit a low heat towards N2adsorption. |
| Databáze: |
Supplemental Index |
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