Montmorillonite system

A very interesting beginning has been made in experimental determinations of the behavior of fatty acids in a water-montmorillonite system at one atmosphere pressure (Johns and Shimoyama, 1972). The basis of the study is the transformation of a long chain molecule to smaller units by breaking specific carbon-carbon bonds. The energy necessary to do this is estimated to be about 46 Kcal/mole in a montmorillonite system, whereas calculations put the value at 56-58 Kcal in a uniquely hydrocarbon... 

However, the effect of temperature is well marked since at 150° C no noticeable transformation is observed while at 250° C the conversion is pronounced. Chromatograms comparable with those obtained for the montmorillonite systems and showing the transalkylation processes are shown in Figure 1. 

Present data illustrate the technique for an in situ determination of surface areas. Related methods had been applied primarily to the study of site distributions in clay minerals, particularly by Russian workers (66), and they were used by Bergmann and O Konski in a detailed investigation of the methylene blue-montmorillonite system (3). In fact, changes in electronic spectra arising from surface interactions received sufficient attention in the past to warrant their review by A. Terenin (65). Most of these investigations involved transmittance spectra but new techniques in reflection spectrophotometry and applications of the Kubelka-Munk relation have facilitated the quantitative evaluation of spectra in highly turbid media (35, 69, 77). Thus, in agreement with the work of Kortiim on powders and anhydrous dispersions (31, 32, 33), our results demonstrate the applicability of the Kubelka-Munk function... 

Logarithm of Stability Constants of the Species Formed in the Solution Phase of the Manganese(ll) lon/EDTA/ Calcium-Montmorillonite System... 

The precipitation and colloid formation of different metal oxide hydroxides is known in soils when the concentration of the ions reaches the value of stability products. In this case, the precipitation can be explained by the thermodynamic properties of the bulk solution. In the lead ion/calcium-montmorillonite system, however, the production of lead enrichments cannot be explained by the... 

Akelah et al. [64] reported the expansion of the d,J0 spacing in MMT in the amine terminated butadiene/acrylonitrile-montmorillonite system (ATBN-MMT) to 14 A (Fig. 3) and of the span between the lamella surface to 5 A, implying horizontal packing of the polymer molecule as shown in Fig. 3. In their patent work, which covered every possible class of polymers, a Toyota group of re-... 

R. Keren and I. Shainberg, Water vapor isotherms and heat of immersion of Na/Ca-montmorillonite systems. II Mixed systems. Clays and Clay Minerals 27 145 (1979). 

Figure 3 shows the kinetics of Ni sorption on pyrophyllite, kaolinite, gibbsite, and montmorillonite from a 3 mMNi solution at pH = 7.5 (16). For kaolinite and pyrophyllite relative Ni removal from solution follows a similar sorption trend with -90% Ni sorbed within the first 24 hours. At the end of the experiments, relative Ni removal from solution was almost complete (Ni/kaolinite system, 97% sorbed after 70 hours Ni/pyrophyllite system, 98% sorbed after 200 hours). Nickel sorption on gibbsite and montmorillonite exhibited a fast initial step. Thereafter, relative Ni removal from solution distinctively slowed down. Relative Ni sorption increased from 42-58% for the Ni/montmorillonite system (time range 0.5-7Q hours) and from 15-41% for the Ni/gibbsite system (time range... 

Figure 7 illustrates the kinetics of Ni sorption on pyrophyllite, along with dissolved Si data from the Ni-treated pyrophyllite and from an untreated pyrophyllite (16). The release of Si into solution shows a similar kinetic behavior as Ni sorption on pyrophyllite. When one compares the Si release rate with the dissolution rate of the clay alone, the Si release rate in the Ni-treated system is strongly enhanced as long as Ni removal from solution is pronounced (Figure 7). Although not shown, a similar correlation between Ni sorption and Si release was observed for the Ni/kaolinite system but not for the Ni/montmorillonite system. The dissolution rate of the Ni/gibbsite system was not determined since the [Al] in solution was too low (<50 ppb) to produce reliable ICP measurements.

Tournassat, C., Y. Chapron, P. Leroy, M. Bizi, and F. Boulahya. 2009. Comparison of molecular dynamics simulations with triple layer and modified Gouy-Chapman models in a 0.1 M NaCl-montmorillonite system. Journal of Colloid and Interface Science 339, no. 2 533-541. doi 10.1016/j.jcis.2009.06.051. 

In contrast, a preferential adsorption as SP was observed when Ci63CiN+ was coadsorbed with Py+-SP, H-SP, and NO2-SP, and normal photochromism has been observed in these systems. Single first-order kinetics has been observed for the Py -SP-CieSCiN -montmorillonite system. The effects of coadsorbing CieSCiN" on the photochromic behavior showed that the CieSCiN" surrounds Py -SP to create a hydrophobic environment. 

Several authors have recently reported on the preparation and characterization of biodegradable polymer-based nanocomposites. Paul et al reported the preparation of PLA/montmorillonite systems by melt intercalation using a... 

Bmardic, M. Ivankovic, H. Ivankovic, and H. J. Mercer. Isothermal and nonisothermal cure kinetics of an epoxy/poly(oxypropylene)diamine/octadecyl-ammonium modified montmorillonite system. Journal of Applied Polymer Science, 100 (2006), 1765 1771. 

Whittig LD, Page AL. Iron adsorption by montmorillonite systems preliminary studies. Soil Sei Soe Proc 1961 25 278-281. 

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