ISSN:
1573-4854
Keywords:
saponite
;
acid treatment
;
surface area
;
porosity
;
acid centres
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract A new deposit of saponite, Vicálvaro (Madrid, Spain), has recently been described in the Madrid Basin (provinces of Madrid and Toledo, Central Spain). The acid treatment of such material and the characterization of the solids obtained are reported in the present paper. The surface area of the natural saponite is rather high, 197 m2/g, related to the very small size of the clay particles due to the sedimentary origin of the deposit. The treatment of the saponitic material at room temperature with 0.62 wt% HCl for times of between 2 and 48 h or with 1.25 wt% HCl solutions for times of up to 6 h produces a partial dissolution of the saponite structure, resulting in the formation of mixtures of unattacked saponite and free silica, with a high development of the textural properties of the solids. The treatment with 1.25 wt% HCl solutions for times of over 6 h results in an almost total dissolution of the structure of the clay, the obtained solids being mainly formed by some delaminated saponite sheets, free silica and insoluble impurities. Solids with a maximum surface area of 462 m2/g and a maximum number of acid centres of 0.98 mmol H+/g are obtained.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009657312123
Permalink
