Mesoporous aluminosilicates (MAs) with excellent hydrothermal stability have been a growing interest because of their potential application in face-centered cubic. The process of improving the P123 utilization efficiency and reducing the water consumption is an important issue for the synthesis and application of MAs. In this study, trace amounts of alcohol ether sulphate (AES) being the co-template were introduced into high P123 concentration to synthesize MAs. The water consumption is reduced 77.3%, and P123 utilization efficiency is increased 1.2 times in comparison to that of the conventional method. In high P123 concentration solution, micelle aggregates were formed without AES, resulting in the formation of less ordered MAs. However, well-dispersed micelles were formed in the presence of AES, which is beneficial for the subsequent assembling process. In addition, the micellar state corresponding to different AES contents and the influence on physicochemical properties of MAs were discussed.
Recent
advances in the synthesis of hydrothermally stable mesoporous
aluminosilicates (MAs) by assembling precursors shed light on their
applications in residue fluid catalytic cracking. Reducing the n(H2O)/n(SiO2) ratio
and thus reducing waste discharge is the key for practical applications
of MAs. In this study, the synthesis of hydrothermally stable MAs
with a decreased n(H2O)/n(SiO2) ratio has been developed based on seed-assisted
crystallization. Crystal seeds were partly dissolved to microcrystallites
on which a large amount of zeolite precursors are assembled and crystallized.
As a direct result of the assembly priority of crystal seeds, the
concentration and viscosity of the liquid phase in the synthesis system
will be decreased greatly. Afterward, the remaining precursors with
proper concentration and viscosity can be assembled with the surfactant
micelles. Therefore, the H2O amount could be largely decreased
by the introduction of crystal seeds.
The degree of damage to heritage structures in arid areas can be particularly serious due to long-term exposure to a harsh arid climate. In this paper, the characteristics of evaporation and cracking of soil taken from heritage structures with different NaCl concentrations are experimentally investigated by subjecting saturated soil samples taken from the Wang-Jing tower in Weihui City, Henan Province. Making soil sample of water content of 110% is used to test the rate of evaporation at a constant temperature and humidity, through which the changes in the evaporation rate, water content, fracture development, and fracture fractal dimension are obtained. The results show that, (1) with higher water content, NaCl can affect the evaporation process by increasing the matrix suction of the soil of the Wang-Jing tower and then affect the cracking process of soil. When 0%, 1%, 2%, and 4% NaCl are added, the residual water content of the samples is 3.15%, 4.23%, 4.82%, and 5.89%, respectively, which show an obvious trend of increasing water content; (2) the period with a stable fracture fractal dimension of the samples is shortened with an increase in NaCl concentration, and its maximum fractal dimension is reduced in turn; and (3) at a lower water content, NaCl crystallizes and precipitates in the pores of the soil, which provide a cementitious effect among the soil particles, thus inhibiting crack development.
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