MONTMORILLONITE AND PILLARED MONTMORILLONITE — SURFACE CHARACTERISTICS

Rok, strany: 1992, 113 - 116

Hydroxy-aluminium and hydroxy-chromium — pillared montmorillonite were prepared by intercalation and subsequent calcination of Ca montmorillonite (MMf) from Jelsovy Potok (Czecho-Slovakia). The cation exchange capacity (CEC) and thermal stability of these materials have been determined using titration methods, X-ray diffraction and DTA measurements. From adsorption-desorption isotherms of nitrogen, which were measured at nitrogen boiling point, surface characteristics of investigated materials such as specific surface area (BET isotherm), micropore volume and specific mesopore surface (t-curve), pore distribution (desorption isotherm), were determined. The results confirmed, that a thermally more stable material with higher specific surface area can be obtained by conversion of the original MMT to pillared form. The CEC decreased from 0.99 meq.g^-1 to 0.66 (Al-pillared MMT) and 0.69 meq.g^-1 (Cr-pillared MMT), thus the total amount of cations, which are able to take part in ion exchange, dropped by about one third. The specific surface area was increased by pillaring from 43 m².g^-1 to more than 270 m².g^-1 , the specific mesopore surface increased more than 2.5 times, while the specific micropore volume was increased more than 10 times. The measurements showed that pillaring opens internal surface (increase of specific micropore volumee), what may be important from the point of view of catalysis, but the MMT structure itself remains preserved (X-ray diffraction measurements, pores distribution calculation).

ISO 690:

Krajcovic, J., Grejtak, F., Hlozek, P., Hudec, P. 1992. MONTMORILLONITE AND PILLARED MONTMORILLONITE — SURFACE CHARACTERISTICS. In Geologica Carpathica Clays, vol. 1, no.2, pp. 113-116.

APA:

Krajcovic, J., Grejtak, F., Hlozek, P., Hudec, P. (1992). MONTMORILLONITE AND PILLARED MONTMORILLONITE — SURFACE CHARACTERISTICS. Geologica Carpathica Clays, 1(2), 113-116.