Papers by Keyword: Al-Pillared Montmorillonite

Abstract: Al-pillared montmorillonite (Al-PILM) prepared with Keggin ions was studied by means of XRD, SEM-EDS and N₂ adsorption-desorption isotherms.The rusults show that, compared to unpillared Na-montmorillonite (Na-M), the interlayer spacing d₍₀₀₁₎ value, BET specific surface area, surface fractal dimension and the proportion of microporous specific surface area of Al-PILM are larger and the surface is relatively rough. The BJH porous volume distribution of Al-PILM is the most probable distribution, and the most probable pore size is about 2 nm, belonging to mesopore. The porous structure of Al-PILM is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. Besides, the results of elemental distribution show that the ions exchange action between Na⁺ and hydroxy-Al cations in pillaring solution occurs in the formation of Al-PILM.

Abstract: Al3+/clay ratio is one of the important factors influencing microstructure of Al-pillared montmorillonite. Microstructure variation laws of Al-pillared montmorillonite prepared under the condition of different Al3+/clay ratio are systematically studied by XRD, FTIR, specific surface area and pore size analysis. The results show that the interlayer spacing and BET specific surface area of Al-pillared montmorillonite are remarkably affected by the Al3+/clay ratio. The interlayer spacing d(001) value and BET specific surface area of Al-pillared montmorillonite increase firstly and then decrease with the increases of the Al3+/clay ratio, and they reach to maximum when the Al3+/clay ratio is 10mmol/g. Besides, the BJH porous volume distribution of Al-pillared montmorillonite is the most probable distribution, and the most probable pore size is about 2 nm, which is attributed to mesopore. The porous structure of hydroxy-Al pillared montmorillonite is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. With the increase of the Al3+/clay ratio, BJH total porous volume and mesoporous volume of hydroxy-Al pillared montmorillonite decreases, while the proportion of microporous volume in the total porous volume increases. The proportion of microporous specific surface area of all the hydroxy-Al pillared montmorillonite samples is about 62% and is much larger than that of Na-M and those of mesopore and macropore, indicating the main action of intercalation of hydroxy-Al pillaring solution into montmorillonite interlayer is to increase the micropore amount.

Abstract: It was shown that chitosan and hydroxy-aluminum pillared montmorillonites were excellent materials for the removal of dyes and metal ions from effluent of dying and finishing. Chitosan/ hydroxy-aluminum pillared montmorillonite nanocomposites are expected to play a multiplex role in the treating process. In this study, the nanocomposite was prepared by incorporating hydroxy-aluminum pillared montmorillonite into chitosan solution that diluted acetic acid was used as solvent for dissolving the chitosan. The ratio of chitosan to the cationic exchange capacity of the montmorillonite was about 1:1, 2:1, 3:1, 4:1 and 6:1, respectively. The nanocomposites were characterized by XRD (X-ray diffraction), SEM (Scanning Electron Microscopy). The experimental results indicated that the presence of hydroxy-aluminum cation was in favor of the chitosan intercalation and the interlayers of MMT was intercalated with the bilayers of chitosan sheets. and they can be used in absorption of organic and metal ions for dying and finishing effluent.