Nanometer size ammonium titanium phosphate was obtained by grinding Ti(SO4)2 and(NH4)3PO4·3H2O via solid-state reaction at room temperature,then mixture was kept at 80 ℃ for 96 h,washed with water to remove soluble inorganic salts and dried at 80 ℃.

It seems that the dealumination and the silicon substitutionof Y zeolites with ammonium hexafluorosilicate undergoes two steps,andthe dealumination rate is much more rapid than that of silicon substitu-tion.

HMCM-22 zeolite was modified with ammonium hexafluorosilicate and characterized by temperature-programmed desorption of ammonia and pyridine adsorption infrared spectroscopy.

hydrothermal,acid and ammonium hexafluorosilicate(AHFS)treatments were used to treat the nanoscale HZSM-5,and the means of XRD,NH3-TPD,XRF,IR and N2 adsorption were used to characterize these treated samples,in order to investigate the effects of dealumination methods on the structure and properties of nanoscale HZSM-5,such as acidity,molar ratio of Si/Al,surface area and pore volume.