Τίτλος:
Extra-framework cation release from heulandite-type rich tuffs on exchange with NH4+
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
The outgoing cations of Greek heulandite-rich tuff samples (heulandite type-III, 91wt.%, mica 4wt.%, feldspar 5wt. %, CEC 2.22meq/g) were analysed upon exchange with ammonium acetate using atomic absorption spectrometry (AAS). The kinetic curves of each cation were investigated over a total time of contact of 720h with sampling at frequent intervals. The materials were examined by powder X-ray diffraction, SEM-EDS, and AAS. The sorption ability was measured using the ammonium acetate saturation method. It was found that Ca2+ presents an unexpected extra-framework release and a surprisingly high degree of exchange (90%). The exchange of Mg (57%) is also worthy of note whereas the behavior of K+ showed an expected rapid initial release. The behavior of Na+ must be similar. However, its lower concentration in the zeolitic material minimizes its overall significance somewhat. On the other hand, Ca2+ and Mg2+ release is kinetically much slower, compared to that of alkali metal ions, and this phenomenon indicates that different exchange energies are needed till final equilibrium. © 2011 Elsevier Ltd.
Συγγραφείς:
Kantiranis, N.
Sikalidis, K.
Godelitsas, A.
Squires, C.
Papastergios, G.
Filippidis, A.
Περιοδικό:
Australasian Journal of Environmental Management
Λέξεις-κλειδιά:
alkali metal; ammonia; ammonium acetate; calcium ion; heulandite; magnesium ion; metal ion; potassium ion; sodium ion; unclassified drug; zeolite, ammonium; atomic absorption spectroscopy; calcium; cation; heulandite; ion exchange; scanning electron microscopy; sorption; tuff; X-ray diffraction, absorption; adsorption kinetics; article; atomic absorption spectrometry; calcium transport; cation transport; magnesium transport; potassium transport; scanning electron microscopy; sodium transport; transport kinetics; X ray powder diffraction, Acetates; Calcium; Cations; Kinetics; Microscopy, Electron, Scanning; Sodium; Spectrophotometry, Atomic; Time Factors; Volcanic Eruptions; X-Ray Diffraction; Zeolites
DOI:
10.1016/j.jenvman.2011.01.013
