New morphological, chemical, and structural data of woolly erionite-Na from Durkee, Oregon, U.S.A.

Abstract

A detailed morphological, crystal-chemical, and structural characterization of erionite from the type locality of Durkee, Oregon, has been carried out by combining field emission scanning electron microscopy (FESEM) and laboratory parallel-beam transmission X-ray powder diffraction (XRPD). According to the crystal-chemical formula (Na5.38K1.99Mg 0.24)[Al7.66Si28.34O72.09] ·29.83H2O, the sample has been classified as erionite-Na. The Rietveld refinement has indicated that the extraframework cations are located at three Ca1, Ca2, and Ca3 sites, the first one containing all available Mg. Moreover, the absence of the additional K2 site found in both dehydrated erionite and erionite-K has been demonstrated for this erionite sample. Furthermore, our results revealed the absence of Fe and Ca although previous investigations have reported the presence of a variable content of both these elements in erionite samples from Durkee. This is relevant information because it is well known from amphibole asbestos that Fe2+ has been claimed to be one of the causes of carcinogenesis by participating in Fenton chemistry and producing free radicals

Crystal chemical and structural modifications of erionite fibers leached with simulated lung fluids

“…Operating conditions were: 15 kV accelerating voltage, 11 mm working distance, 0° tilt angle. Chemical analyses were collected by dispersing a small aliquot of fibers in distilled water in a beaker and subsequently pipetting and depositing a few droplets of the dispersion onto a stub (Cametti et al 2013). This procedure was carried out to avoid the contribution to the chemical data of impurities still persisting despite the enrichment procedure (Cametti et al 2013).…”

“…Chemical analyses were collected by dispersing a small aliquot of fibers in distilled water in a beaker and subsequently pipetting and depositing a few droplets of the dispersion onto a stub (Cametti et al 2013). This procedure was carried out to avoid the contribution to the chemical data of impurities still persisting despite the enrichment procedure (Cametti et al 2013). Final crystal chemical formulas were calculated, after renormalization of the chemical analyses hypothesizing a water content of 18.5 wt% (corresponding to ca.…”

“…The chemical analyses of several erionite samples revealed the presence of iron, although this zeolite is a nominally Fe-free phase (Eberly 1964;Dogan et al 2006). However, it has been shown that iron was located at the zeolite surface as iron oxide nanoparticles ) or as a thin coating of iron-bearing silicates (Cametti et al 2013). Five mechanistic hypotheses for asbestos carcinogenicity have been proposed (Kane et al 1996): (1) generation of free radicals damaging DNA; (2) physical interference with mitosis;…”

Prismatic to Asbestiform Offretite from Northern Italy: Occurrence, Morphology and Crystal-Chemistry of a New Potentially Hazardous Zeolite

“…As previously suggested [62,63], to minimize the alkali metal migration, chemical data were acquired using a low counting time and a raster scan mode to reduce the temperature increase. The reliability of the chemical analysis used to classify the offretite samples was evaluated by using the charge balance error formula (E% within ±10%; [51,64]), the Mg-content [65] and the K-content tests, similarly to erionite [66].…”

Thermal Stability of Woolly Erionite-K and Considerations about the Heat-Induced Behaviour of the Erionite Group

“…No restraints on bond distances and angles were imposed. Owing to the peculiar habit of the fibres, we applied the ellipsoid-model of [27] describing the diffraction-vector dependent broadening of diffraction maxima as successfully done by Cametti et al [28] in the case of woolly erionite-Na from Durkee, OR, USA. The shape ellipsoid parameters b ij were constrained as b 11 = b 22 = 2b 12 ; b 13 = b 23 = 0, and the orientation of the ellipsoid has the principal radii r a ⊥ c and r c c.…”