Montmorillonite complexation

Fewer controlled experiments have been carried out for purely aquatic systems. Montmorillonite complexes with benzylamine at concentrations below 200 pg/L decreased the extent of mineralization in lake-water samples, although a similar effect was not noted with benzoate (Snbba-Rao and Alexander 1982). Even in apparently simple systems, general conclusions cannot therefore be drawn even for two structurally similar aromatic compounds, both of which are readily degradable nnder normal circumstances in the dissolved state. 

Saha U.K., Taniguchi S., Sakurai K. Adsorption behavior of cadmium, zinc and lead on hydroxyaluminum- and hydroxyaluminosilicate-montmorillonite complexes. Soil Sc Soc Am J 2001 65 694-703. 

Yamanaka S, Kanamaru F, Koizumi M. 1974. Role of interlayer cations in the formation of acrylonitrile-montmorillonite complexes. J Phys Chem 78 42-44. 

Gianfreda L, Rao MA, Violante A (1992) Adsorption, activity, and kinetic properties of urease on montmorillonite, aluminum hydroxides, and Al(OH)x-montmorillonite complexes. Soil Biol Biochem 24 51-58... 

Al203-montmorillonite complexes were prepared according to the procedure described by Sterte and Otterstedt (19). The samples used in this study were prepared from untreated aluminum chlorohydrate and from aluminum chlorohydrate hydro thermally treated at 120° and l O C (catalyst designations Ml, M2 and M3). The catalysts were air dried and ground in a ball mill. The fraction 0-100 microns was separated and steamed in a muffle furnace at 750°C for 18 hrs. As a reference, a sample containing 20 % REY in a kaolin-binder matrix was prepared and treated in the same manner (catalyst M ). 

Table VIII. Catalytic cracking over alumina-montmorillonite complexes...

The importance of diffusion enhancement to heavy oil cracking is further illustrated by the alumina-montmorillonite complexes which crack heavier feeds, i.e. Wilmington fraction No. 6, more effectively than REY. When used as matrices for REY, the alumina-montmorillonites results in considerably more active catalysts, at the same zeolite content, compared with a catalyst having a kaolin-binder matrix, while the selectivity properties differs very little between the two types of catalysts (Sterte, 3. Otterstedt, 3-E. Submitted to Appl.Catal.). 

BRYD0N (J.E.) and KODAMA (H.), 1966. The nature of aluminum hydroxide-montmorillonite complexes. Amer. Min. 51, 875-89. 

Naidja, A., and Huang, P. M. (1996). Deamination of aspartic acid by aspartase-Ca-montmorillonite complex. J. Mol. Catal. A Chem. 106, 255-265. 

The preparation of hydrothermally treated ACH-solutions used in the preparation of alumina montmorillonite complexes (AMC) is described in references (9,10). The ACH-solution (C i = 0.176 M, AI2O3/CI = 0.93) was hydrothermally treated in an autoclave for 2 hr. at temperatures in the range 120-160OC. After deionization and reacidification (to pH 3.9) the colloidal suspensions formed were used at a concentration corresponding to 6.0 g AI2O3 per 1, for the preparation of AMCs. 

At our laboratory we have studied aluminum-oxide montmorillonite complexes prepared from ACH-solutions hydrothermally treated at temperatures up to 160 0 (9). Hydrothermal treatment of ACH at temperatures above about 120 0 yields positively charged, fibrillar boehmite in colloidal suspension (1 ). The size of the boehmite fibrils increases with increasing temperature and time of hydrothermal treatment. Ion-exchange of montmorillonite with these positively charged fibrils resulted in AMCs with... 

Table II. Catalytic Cracking over Alumina-Montmorillonite Complexes alone...

Saha, U. K., Taniguchim, S., and Sakurai, K. (2002). Simultaneous adsorption of cadmium, zinc, and lead on hydroxyaluminum-and hydroxyaluminosilicate-montmorillonite complexes. Soil Sci. Soc. Am. J. 66. 117-128. 

Sakurai, K., and Huang, P. M. (1995). Cadmium adsorption on the hydroxyalu-minium-montmorillonite complex as influenced by oxalate. In Environmental Impact of Soil Componenet Interactions, Vol. Il, Metals, Other Inorganics and Microbial Activities, ed. Huang, P. M., Berthelin. J., Bollag, J.-M., McGill, W. B., and Page, A. L., Lewis Publishers, Boca Raton. FL, 39-46. 

Zhu, M., Xie, M., and Jiang, X., Interaction of fluoride with hydroxyaluminum-montmorillonite complexes and implications for fluoride-contaminated acidic soils, Appl. Geochem., 21, 675, 2006. 

Pinck et al. (1954) prepared several protein-montmorillonite complexes and studied their rates of decomposition by microorganisms. They observed that in complexes containing about 10% protein and having a c-spacing of near 15 A, the protein was present as a monolayer between the crystal lattice sheets. In such preparations only about. 20% of the protein was decomposed in four weeks. Apparently most of this represents protein that was not inside the interlamellar space that which was inside the lattice was decomposed very slowly, as shown in Fig.9.2. Where two or more layers of proteins were present they decomposed at about the same rate as where protein alone was present without clay. 

Yariv and Lapides [104] demonstrated the utility of thermo-XRD analysis in the study of organo-smectite complexes, such as montmorillonite complexes with anilines, fatty acids, alizarinate, and protonated Congo red, and of complexes of other smectites with acridine orange. The technique is very efficient in determining whether the adsorbed organic species penetrates into the... 

FIGURE 8 Molecular model of I8C6/NH4 -montmorillonite complex showing the cation-ligand interaction (A) and the arrangement in the interlayer space of the silicate (B). (Adapted from Ref. 46. Reproduced by permission of The Royal Society of Chemistry.)... 

Y. Zang, W. Xu, D. Qiu, D. Chen, R. Chen, and S. Su, Synthesis, characterization and thermal stability of different polystyryl quaternary ammonium surfactants and their montmorillonite complexes. Thermochimica Acta, 474 (2008), 1-7. 

The intercalation reaction of organic molecules with montmorillonite has been widely studied [l 3]. Some studies on the thermal behavior of n-alkylammonium-montmorillonite complexes has also been reported [4-5], but no research on the reaction kinetics of desintercalation. 

Fig. 1. X-ray diffraction patterns of Na-(a), Ca-(b), Zn-(c,d) and Cu-(e) montmorillonite complexes with CDen (FeXa radiation). CDen addition levels (mmolg ) 1.0 (a-c), 2.0 (d), 1.4 (e). The data for the Cu-complex are from [1].

The evolved gas of the first step around 300 °C of the montmorillonite complex was identified as n-hexylamine by GC-analysis (Fig. 3), which indicates the simple desintercalation of amines. According to the TG-analysis of the first step, approximately 25% of the total weight decrease was measured, and this indicates that the layer charge originating from the octahedral substitution might be 0.18 per unit cell composition. On the basis of this result, along with that of the layer charge estimation by the n-alkylammonium method, the chemical equation of the first step can be formulated as follows ... 

Fig. 3. G.C. results for the evolved gas from the n-hexylammonium montmorillonite complex at 300 "C.

FIGURE 10 Arrangement of interlayer species in a benozonitrile/Mg-montmorillonite complex. The ions are midway between the layers and coordinated to four benzonitrile molecules (nearly perpendicular to the layers) and two water molecules. (After Ref. 

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