An overall experimental analysis: Effects of synthetic parameters on the degree of order of mesochannels in nano-sized Al-MCM-41

Abstract

In an experimental and statistical study, the effects of five synthesis parameters on the degree of order of nano-sized Al-MCM-41 were basically investigated. In a series of designed experiments, hydrothermal conditions (temperature and time), Si/Al, NaOH/Si, and cetyltrimethylammonium bromide/Si molar ratios were studied each at three levels. Degree of order of mesoporous channels was evaluated using small angle XRD. Nitrogen adsorption-desorption technique, scanning and transmission electron microscopy (SEM-TEM), and field-emission SEM were also applied to detect the textural properties and the morphology of prepared nanoparticles. Energy-dispersive X-ray spectroscopy and mapping (EDS-Map), inductively coupled plasma-optical emission spectroscopy, and small angle X-ray scattering were provided as complementary analyses. An accurate reduced quadratic equation was proposed as a function of effective terms in good agreement with the experimental results. Based on the analysis of variance, the amount of aluminum incorporated, sodium hydroxide, and the hydrothermal treatment duration was found to possess more dramatic effects on the degree of order than the other factors. The optimum conditions for the synthesis of a well-ordered Al-MCM-41 were also obtained with the lowest template and the minimum hydrothermal duration verified by two validation tests.