Synthesis Of Mesoporous Aluminosilicates Using P123/SDS/CS Triple Template Method

Mesoporous aluminosilicates(MAs)with excellent hydrothermally stability is emerging as the most important materials in catalytic cracking of heavy oil molecules(FCC).In our previous investigation,the hydrothermal stability of MAs was greatly improved by introduced Y precursor into the wall of MAs.This technology was successfully employed in industrial production of MAs for the first time,and hydrothermally stability of the obtained MAs is comparable to that of USY.However,this progeress still suffer from low utilization efficiency of P123 and H2O.In order to resolve the above problems,the method of mother liquor recycling,crystal seed method and composite template method was employed to synthesize MAs,which greatly improved the utilization efficiency of P123 and H2O:(1)The mother liquor cycling method can reuse the unreactive substances in the mother liquor(e.g.Si,Al,P123 and H2O).Therefore,the utilization efficiency of the template and water can be improved.(2)In the seed-assisted method,the MAs were partly dissolved in the mixture as a crystal seed(CS),which can provide a growth surface for the crystallization of Y zeolite precursor.Due to the templating role of CS,the utilization efficiency of P123 was increased greatly.In order to ensure the dispersity of CS,the water content of the system is higher,leads to the low utilization efficiency of the CS and water.(3)In the composite template method,anionic surfactants SDMBS(dodecyl dimethyl benzene sulfonate)are dissolved in the P123 micellars core and mixed micelles will be formed,the addition of SDMBS cause enhancement of micelles hydration and lead to increased dispersity of P123 micelles,so that the utilization efficiency of the P123 and water iccreased.In order to prepare high hydrothermal stability of MAs with a increase of utilization efficiency of P123 and water,the following research is conducted by combining the advantages of above methods.1.In the composite template mother liquor recycling:An anionic surfactant SDS(Sodium dodecyl sulfate)was added in a high concentration synthesis,composite micelles would be formed due to the interaction of hydrophobic chains in SDS and PPO chains of P123.As a direct consequence,the dispersity of micelles would be enhanced.As a result of this,mesostructured ordering would be improved with greatly increased utilization efficiency of P123 and water.The utilization efficiency of P123 and H2O are 0.80 g/g MAs and 15.89 g/g MAs,the total specific surface area and the total volume are 611.1 m2·g-1 and 0.72 cm3·-1,after hydrothermal treatment,the total specific surface area and the total volume retaining ratio are 36.3%and 59.7%.2.In the triple template of P123/SDS/CS synthesis method:active crystal seeds would be formed due to the interaction of hydrophobic chains in SDS and hydrophobic surface of CS,as a direct consequence,the dispersity of CS would be enhanced.As a result of this,mesostructured ordering would be improved with greatly increased utilization efficiency of P123,CS and water.The utilization efficiency of P123 is 0.73 g/g MAs,the utilization efficiency of CS is 0.26 g/g MAs and the utilization efficiency of H2O is 20.10 g/g MAs,the total specific surface area and the total volume are 625.5 m2·g-1 and 0.77 cm3·g-1,after hydrothermal treatment,the retaining ratio of total specific surface area and the total volume are 37.2%and 55.8%.