Synthesis of KIT-6 & SBA-15-S mesoporous silica based functionalized mixed matrix membranes for the separation of CO2/CH4

Abstract

The main idea of this dissertation is to synthesize the meso porous materials KIT-6 & SBA-15-S utilize this mesoporous silica based materials in MMMs for the separation purposes. Synthesis methods for mesoporous silica based membranes are developed to get better the transportation, permeability, surface area of membranes and pore volume of membranes. These membranes were tested under different conditions for the separations. The collected studies of mesoporous silica based materials and polyimide membranes showed that appropriate functionalization on newly synthesized novel membranes leads to promising structural and permeation properties. The carbon dioxide emission is the severe environmental issues. It is the fact that its concentration has been increased in last fifty years and considerably in 15 years. Intergovernmental Panel reports have been published on the issue of climate change. In his report, there is boost in atmospheric CO2 concentration by an amount of 100 ppm since last 250 years up shown that. The concentration of CO2 was previously 275-285 ppm and now it has reached to 379 ppm in 2005. The amount of CO2 can be lessened by replacing fossil fuels by environment friendly green fuels, by amine absorption, cryogenic distillation and absorbent liquid absorption through membrane contactor. In this present work mesoporous, silica materials have been prepared and utilized them as filler in Polymer membranes for the separation purposes for CO2 from CH4& N2. For this, KIT-6 is synthesized by mixing 6 g of P123 &217 g of distilled water along with 11.8 g of concentrated HCl. When the above mentioned solution is formed add 6 g of 1-butanol under constant stirring at 35 ◦C. After 1 h, when homogenized solution is formed add 12.9 g of Tetra Ethyl Orthosilcate drop wise at 35 ◦C. This mixture is kept at constant stirring for 24 h at the temperature of 35 ◦C. Then this solution is moved to Teflon made bottle and placed in Oven at 100 ◦C for 24 h. The obtained product from the oven is hydrothermally treated. After this, it is filtered to obtain the precipitate, dried by rotameter at 60-70°Cand done calcination at 550 ◦C for 5 h to utilize as filler in membranes. SBA-15-Spherical is prepared by 1Tetra Ethyl Ortho silicate: 0.017P123:0.6 mesitylene: xKCl: 5.85 HCl: 165 H2O. First 4 g of P123 and a definite amount of KCl (x = 2) is dissolved in 120 g of H2O along with 23.6 g of concentrated HCl at 25°C till the complete dissolution. Then 3 g of mesitylene is added in the solution, kept it under constant stirring for 2 h. Add 8.5 g of Tetra Ethyl 2 | P a g e ortho silicate drop wise, and stirred for 10-20 min. This mixture is then shifted to Teflon bottle and kept static at 35◦C for 24 h followed by in Oven at 100 ◦C for 24 h. The obtained product from the oven is hydrothermally treated. After this, it is filtered and cleaned to obtain the precipitate. Then it is dried in rota meter at 60°C and done calcination at 550 ◦C for 5 h so that it could be used as filler. These SBA-15-Spherical& KIT-6 were characterized by SEM-EDS, XRD and BET analysis for their conformity. The potential of these mesoporous materials is to utilize into PI membranes for the separation purposes for CO2 from CH4 and N2 under different conditions. These PI membranes were synthesized by dissolving P84 into NMP by evaporation technique and impregnate mesoporous materials in it with different loadings (10%, 20% and 30%). After the impregnation of these calcined mesoporous materials KIT-6 and SBA-15-S into mixed matrix membranes, the permeation results are improved as compared to MCM-41 mesoporous materials mixed membranes. While selectivities slightly decreased due to less interaction of filler particles with CO2. This Interaction is increased by the functionalization of these membranes with some group like sulphonic group or amine group. The interaction between Polymer and filler is increased after the impregnation of mesoporous materials as Tg of the PI membranes increases. If we compare the SBA-15-S and KIT-6, permeation results with each other than it is clearly shown that SBA-15-S has shown better permeation results due to its large pore volume. As SBA-15-S has large pore volume, so it may capture greater molecules than that of KIT-6.