https://doi.org/10.1093/ce/zkac020
“Hexagonal mesoporous silica MCM-41 was synthesized by dissolving 2 g of pore-generating agent, CTAB, with 120 mL of deionized water under constant agitation. After the CTAB was completely dissolved, 7.5 mL of ammonia solution was slowly added and the mixture was stirred for 1 hour. Then, 10 mL of TEOS, which was the precursor of silica to obtain the suspension solution, was added to the well-mixed solution. The suspension was stirred at room temperature for 12 hours. Later it was filtered using Whatman® filter paper grade 4, washed with deionized water until neutral and then dried at 100°C in an oven for 12 hours. Synthesized MCM-41 was ground to a fine powder before calcination at 550°C in a furnace with a heating rate of 10°C/minute for 5 hours. The procedure of MCM-41 synthesis was similar to the previous work [68], which was adopted from Loganathan and Ghoshal [58]. For use as adsorbents for CO2 capture, the synthesized MCM-41 was further modified with amines via the wet impregnation method [69]. It was done by mixing a certain amount of amine with 50 mL of methanol. The weight concentration of amines was varied at 30, 50 and 60 wt%. Then, 1 g of synthesized MCM-41 powder was added to the amine–methanol solution. The reaction was refluxed at 70°C for 6 hours and the suspension sample was dried in a rotary evaporator to remove the methanol. The amine-impregnated MCM-41 was kept in a desiccator before use.”