Potassium calcium zeolite

Independently vibrating water molecules were used to explain the INS from a series of A-type zeolites. Sharp transitions appeared at low frequencies in the lithium, 63 cm", and sodium, 29 cm", zeolites but the potassium and calcium zeolites showed no bands at all in this region [14]. The relatively sharp features of the INS spectrum of ZSM-5 with low water content gave way at higher water content to broader, less structured spectra. The spectra resembled ice Ih in form, see below, but had distinctly different librational band frequencies. Whereas, in ice these bands are at about 600 cm , in the ZSM-5-water system they appear about 500 cm and about 400 cm in leucite-water [15]. A similar frequency drop is also seen in the INS of water, ca 3%, on silica gel [16]. This is related to the earlier observation that the more open the structure of bulk water in a material then the lower will be the librational band frequencies [17]. The structural aspects of water in confined geometries has been reviewed recently [18]. 

Sources and Production Potassium is highly reactive and does not occur in nature as a free metal. The abundance of potassium in the 16 km-thick Earths crust - mainly in silicates (feldspars, micas) - is 25.9 g kg k In the frequency list of the elements, potassium occupies seventh place. Its abundance in sea vater is almost as great, due to the veathering of potassium-containing minerals. After veathering of the rocks, potassium is bound by the calcium zeolites of the soils, and only part of it reaches the sea (0.38 g sea water). 

Zeolites are crystalline aluminosilicates of group lA and group llA elements, such as sodium, potassium, magnesium and calcium [2]. Chemically, they are represented by the empirical formula ... 

Zeolite molecular sieves are composed of silicon and aluminum and can be natural or manmade minerals. Molecular sieves are crystalline, hydrated aluminosilicates of (most commonly) sodium, calcium, potassium, and magnesium. The alumininosilicate portion of the structure is a three-dimensional open framework consisting of a network of A104 and Si04 tetrahedra linked to each other by sharing all of the oxygens (Sherman, 1978). Zeolites may be represented by the empirical formula... 

Physicochemical properties of L zeolites and of clinoptilolite were studied by adsorption, chromatographic, spectral, and ther-mogravimetric methods. The sodium form of L zeolite is characterized by better adsorption with respect to water and benzene vapor and by higher retention volumes of C C hydrocarbons and CO than potassium and cesium forms. The activation energy of dehydration determined by the thermogravimetric method decreases on going from the sodium to cesium form of L zeolite. When calcium is replaced by potassium ions in clinoptilolite, the latter shows a decreased adsorption with respect to water vapor. The infrared spectra of the L zeolite at different levels of hydration show the existence of several types of water with different bond characters and arrangements in the lattice. 

The similarity in the adsorption behavior of krypton on the three kinds of mica surfaces suggests that the adsorption here is primarily due to dispersion forces, with very little contribution from ion-induced dipole forces. The results of Barrer and Stuart (1) for the adsorption of argon on various ion-exchanged forms of faujasite are similar. They found that while calcium, strontium, and lithium faujasite—i.e., the materials containing cations with greater polarizing power—did show heat effects correlatable with ion-induced dipole interactions, no such effects were observed with sodium, potassium, or barium zeolites. With the latter materials, they also concluded that the adsorbed argon possessed appreciable mobility. 

Zeolites, also known as molecular sieves, are important alternative builders for powdered laundry detergents and replaced phosphate salts that were banned for legislative reasons. Zeolites exist in the form of calcium, sodium, magnesium, potassium, and barium salts. 

In an attempt to synthesize and capture silver clusters in this way, empty Ag, K-A was exposed to Cs(g) at 250 °C. The structure of the product showed that the potassium ions had all been reduced and were no longer present in the zeolite. The silver ions also had all been reduced to atoms, but most of these were found as hexasilver molecules at the very centers of the large cavities. Each hexasilver molecule was surroxmded by fourteen Cs" " cations. When this reaction was done with Ag, Ca-A and Rb(g) instead, hexasilver molecules each associated with thirteen Rb" " ions were found at the same position. The product calcium atoms had left the structure. 

The behavior of zeolites in biological systems is a bit mysterious. For example, treatment of yeast mitochondria with zeolite A or X in the sodium or potassium cation forms disaggregates the mitochondria and solubilizes cytochrome oxidase in an aqueous system. However, the same zeolites in calcium or magnesium form showed little activity of this type (67). Similarly, zeolite A can disrupt bacterial cells (83). 

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