| Montmorillonite, the primary constituent of bentonite, is a clay mineral with expandable layer structure. Isomorphous substitution of montmorillonite results in a net permanent charge, therefore it has the reversible cation exchange capability and very plastic properties. Mesoporous pillared montmorillonite can be prepared by introducing gallery templates, such as simple metal cations, quaternary ammonium cations, long chain amines, and hydroxyed inorganic metal ions. Thus formed pillared-montmorillonites have improved capabilities to adsorb hydrophobic contaminants and are widely used as sorbents to treat industrial wastewaters. They also have a lot of applications in other various areas.This dissertation first gives a comprehensive review, which is on the recent progress in the research and development on the pillaring and applications of montmorillonites. Special attention is paid to the pillaring of montmorillonites with hydrated polymeric inorganic cations, such as OH-A1. With greatly improved sorption property, surface acidity and thermal stability, pillared montmorillonites possess great promise to be used as catalysts and adsorbents, especially for environmental protection and pollution control applications.Because the montmorillonite content of natural bentonite clay is usually low, the methods of purification and ion exchanging of raw bentonite with NaCl into Na-montmorinollite are described and investigated. The procedure and conditions are optimized. It is found that (NaPO3)6 solution is the best dispersing agent for the purification of montmorillonite. The optimum concentration of (NaPO3)6 solution is about 0.15 wt% with the pH value of 7.0. When the raw bentonite is ion exchanged with NaCl, the optimum concentration of NaCl is about 1.0 mol/dm3 with the pH value of 5.0-6.0. The data of XRD, F-XRD and other chemical analysis shows that the content of montmorillonite in the above-treated bentonite increased to more than 90%. The spacing distance (d(001)) value of Na-montmorinollite reduces to 12.73 A,indicating that Ca-montmorillonite has been successfully converted to Na-form.Fe3+-, A13+-, Na-organo-, Fe-organo, Al-organo- and OH-Al-pillared montmorillonite have been synthesized, characterized and studied by various analysis techniques, such as IR, XRD, F-XRD, BET analysis. (1) The chemical compositions results from F-XRD show that content of Na2O decreased obviously. (2) The IR spectra of organic-montmorillonites indicate that the long chain quaternary ammonium cation has been intercalated to the inner space of montmorinollite. The IR spectrum of OH-Al-montmorillonite suggests that hydroxy-Al polymers form complexes in the interlayer space of montmorillonites. (3) The data of XRD show that d(001) of the OH-Al-montmorillonie sample is 18.67 A, which indicated that Alo7+ Keggin ions had been exchanged between the layers. (4) BET and pore distribution analysis show that the surface area of OH-A1- montmorillonite sample was 229.6 m2/g, over 9 times that of Na-montmorillonites. (5) The shape of mesopores of these pillared montmorillonites have also been suggested, according to the nitrogen adsorption-desorption isotherms.Recent research pay great attention to organo- and simple metal- motmorillonite, therefore, one of the most important parts of this dissertation is about hydroxy-metal. Based on former work, a new method has been used to prepare OH-Fe-(m=OH7Fe=1.0)andOH-Fe-Al (m=1.0, Fe/(Fe+Al)=0.5) -montmorillonite and other OH-Fe-pillared montmorillonite. The above-made montmorillonites have also been characterized. The major results are summarized as follows: (1) According to F-XRD analysis, the content of Fe as Fe2O3 increased dramatically, from 2.27% in Na-montmorillonite to 33.07% in OH-Fe-montmorillonite(m=1.0), and to 35.37% in OH-Fe- montmorillonite (m=2.0) , over 15 times higher than before. (2) The IR spectra of OH-Fe- and OH-Al-Fe-montmorillonites suggest that hydroxy-Fe polymers form complexes in the inner space of montmorillonites. (3) The d(001) value of the pure OH-Fe-montmor...
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