Ca-montmorillonite

Names bentonite, clay, montmorillonite, Na-montmorillonite, Ca-montmorillonite, hydrated sodium calcium aluminum magnesium silicate hydroxide... 

Chem. Descrip. Montmorillonite CAS 1318-93-0 EINECS/ELINCS 215-288-5 Uses Thixotrope, suspension stabilizer, vise, control agent, syneresis reducer for aq. systems, personal care, home care Features Rec. where whiteness is desired Properties Wh. fine powd. 75% min. thru 200 mesh odortess vise. 500 cps min. (5% slurry) brightness 82 pH 9.5-10.5 (2% sluny) 8% max. moisture... 

Our recent interest is, however, on the in-situ intercalative polymerization of pyridine substituted acetylenic monomer (2-ethynylpyridine (2EPy)) within the galleries of Ca -montmorillonite (Ca -MMT) (5). In this process, it is believed that monomer first intercalates into the galleries of montmorillonite, and then the interaction with clay surface initiates the polymerization (5). The X-ray... 

Materials Ca -Montmorillonite (Ca-MMT) was purchased from Clay Minerals Repository with cation exchange capacity of 1.20 mequiv/g. 2-ethynylpyridine (2EPy) was purchased from Farchan Laboratory and used as received. 

Some may use the combined latex compounding and melt mixing approach to produce natural rubber nanocomposites. For instance, natural rubber/Ca-montmorillonite (Ca-MMT) nanocomposites with well exfoliated Ca-MMT were prepared by a combination of latex compounding and melt mixing. Firstly, a high Ca-MMT content masterbatch was co-coagulated by natural... 

Clay-catalyzed asymmetric Diels-Alder reactions were investigated by using chiral acrylates [10]. Zn(II)- and Ti(IV)-K-10 montmorillonite, calcined at 55 °C, did not efficiently catalyze the cycloadditions of cyclopentadiene (1) with acrylates that incorporate large-size chiral auxiliaries such as cA-3-neopentoxyisobornyl acrylate (2) and (-)-menthyl acrylate (3, R = H) (Figure 4.1). This result was probably due to diffusion problems. 

For example. Date et al. (1983) recognized the following alteration zones in the Fukazawa Kuroko mine area of Hokuroku district from the centre (near the orebody) to the margin (1) sericite-chlorite zone (zone 111 in Figs. 1.20-1.22) characterized by quartz + sericite Mg-rich chlorite (2) montmorillonite zone (zone 11 in Fig. 1.20) characterized by Mg-Ca-type montmorillonite + quartz kaolinite calcite sericite Fe-rich chlorite and (3) zeolite zone (zone 1 in Fig. 1.20) characterized by clinoptilolite + mordenite + Mg-Na-type montmorillonite cristobalite calcite or analcime + Mg-Na-type montmorillonite + quartz calcite sericite Fe-rich chlorite (Fig. 1.20). 

This equation shows that activity of Ca + is related to pH, concentration of H2CO3 and temperature. Because pH is related to the concentration of Cl for the equilibrium curves 1 and 2 in Fig. 2.14, the relationship between the concentrations of Ca " " and Cl" can be derived for calcite-albite-sericite-K-feldspar-quartz equilibrium (curves 4 and 7 in Fig. 2.14) and calcite-albite-sericite-Na-montmorillonite-quartz equilibrium (curves 5 and 8 in Fig. 2.14) with constant w2h2C03- The range of zh2C03 in the solution in equilibrium with calcite is assumed to be 10 to 10 . The other equilibrium curves for the assemblage including Ca minerals are also drawn (Fig. 2.14). These assemblages are wairakite-albite-sericite-K-feldspar-quartz (curve 3), Ca-montmotillonite-albite-sericite-Na-montmorillonite-quartz (curve 6), Ca-montmorillonite-albite-sericite-K-feldspar-quartz (curve 9) and anhydrite (curve 10). The effect of solid solution on the equilibrium curves is not considered because of the lack of thermochemical data of solid solution. 

Fig. 2.14. The variation of concentration of with concentration of CP in aqueous solution in equilibrium with a given mineral assemblage at 250°C. I Equilibrium curve based on albite-sericite-Na-montmorillonite-quartz-aqueous solution equilibrium and Na-K-Ca relationship obtained by Fournier and Truesdell (1973). 2 Equilibrium curve based on albite-K-feldspar-aqueous solution equilibrium and Na-K-Ca relationship obtained by Fournier and Truesdell (1973). 3 Wairakite-albite-sericite-K-feldspar-quartz. 4 Calcite-albite-sericite-K-feldspar-quartz (/jjhjCO, = 10 ). 5 Calcite-albite-sericite-Na-montmorillonite-quartz (mH2C03 = 10 ). 6 Ca-montmorillonite-albite-sericite-Na-montmorillonite-quartz. 7 Calcite-albite-sericite-K-feld-spar-quartz (mnjCOj = 10 ). 8 Calcite-albite-sericite-Na-montmorillonite-quartz (mHjCOj = 10 ). 9 Ca-montmorillonite-albite-sericite-K-feldspar-quartz. 10 Anhydrite = 10 ). (Shikazono, 1976)...

Four billion years ago, the Earth s thin crust consisted of geochemicals (i.e., compounds containing the elements Si, O, Al, Fe, Mg, Ca, K and Na, as well as traces of other elements). Thus, some biogenesis researchers believed that the first replicating material consisted of geochemical material rather than substances containing carbon and other bioelements. Clay minerals in particular were included in experimental and theoretical studies. The most important are kaolinite and montmorillonite the latter was, and still is, used in many experiments carried out to simulate prebiotic reactions. 

Although both methods are thermodynamically equivalent it appears that K. remains independent of surface composition for ex anges of Na versu a, Ca (11-12), versus Co, Cu, Ni, Cd (13) and versus Cu (14) in montmorillonites. In contrast Kg values increase with occupancy in all these equilibria. 

The exchange of Ca-ethylenediammonium in a series of montmorillonites (26) shows AGfix values which increase with charge... 

Fig. 7 shows the progressive transformation of montmorillonite to iliite/smectite interlayers by the gradual development of both the characteristic Cs and Rb high selectivity profiles observed for pure illite and the high Cs-Rb selectivity at+ race fadings. The data can be simulated (see table VI for the Ca - Cs case) using a consistent set of intrinsic selectivity coefficients and identical site group capacities for the Ca-Cs and... 

Berteau montmorillonite subjected to 2 (i), 5 ( ) and 10 ( ) wetting-drying cycles (101). Jurves re a simulation. Table VI shows these data for the (Ca - Cs ) equilibrium. Reproduced with permission from Ref. 101. Copyright 1985, The Clay Minerals Society. 

TABLE VI. InK values and site group capacities (meq 100/g) for simulating the Cs Ca equilibria at 25°6 of potassium-exchanged Camp Berteau montmorillonite subjected to alternate wettingdrying cycles... 

Selectivity decreased through the weathering sequence mica > i 11 ite = vermicul ite > montmorillonite. Selectivity for K over Ca has been ascribed to the low hydration number and polarizability of K (19), to wedge sites at the weathered edge of clay... 

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