Recycling of surfactant template in mesoporous MCM-41 synthesis

29th Symposium of Malaysian Chemical Engineers 2016

Lai, J.Y.^1 ; Twaiq, F.^1 ; Ngu, L.H.^1

Faculty of Engineering, Computing and Science, Swinburne University of Technology, Sarawak Campus, Jalan Simpang Tiga, Sarawak, Kuching

93350, Malaysia^1

关键词: Critical micelle concentration (cmc);    Hexadecyltrimethylammonium bromide solutions;    Mesoporous MCM-41;    Silicate anions;    Surfactant template;    Synthesis procedure;    Synthesis process;    Tetraethyl orthosilicates;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/206/1/012044/pdf
DOI  :  10.1088/1757-899X/206/1/012044

来源: IOP

【 摘 要 】

The recycling of surfactant template is investigated through the reuse of the surfactant template in the mesoporous MCM-41 synthesis process. In the synthesis of MCM-41, tetraethylorthosilicate (TEOS) solution in water was utilized as the silica source while hexadecyltrimethylammonium bromide (CTAB) solution in ethyl alcohol was used as a surfactant template. The synthesized gel is formed thoroughly by mixing the two solutions under acid conditions with a pH value of 0.5 for 1 hour and kept for crystallization for 48 hours. The as-synthesized MCM-41 powder is recovered by filtration while the filtrate (mother liquor) was then reused for the second synthesis cycle. The synthesis procedure was repeated till no further solid product was formed. The synthesized gel was not produced in the unifying solution in the fifth cycle of MCM-41 synthesis. The quality of the calcined MCM-41 powder produced in each synthesis cycle was evaluated by calculating the amount of MCM-41 produced and the surface area of the powder product. The result showed that 1.28, 0.37, 1.64, 1.90 and 0.037 g were obtained in the 1st, 2nd, 3rd, 4thand 5thsynthesis cycle, respectively. The surface area of the powder produced was found to be 1170, 916, 728, and 508 m2/g for 1st, 2nd, 3rdand 4threspectively. The concentration of the surfactant template has reached value lower than the critical micelle concentration (CMC) and remained constant after the 4thcycle. There was no further formation of gel due to low availability in the interaction between silicate anions and surfactant cations when the amount of TEOS was fixed for every synthesis cycle.