Functionalized Ordered Mesoporous MCM-48 Silica: Synthesis, Characterization and Adsorbent for CO2 Capture

• Published in: International journal of molecular sciences Vol. 24; no. 12; p. 10345
• Main Authors: Borcănescu, Silvana, Popa, Alexandru, Verdeș, Orsina, Suba, Mariana
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19.06.2023; MDPI
• Subjects: Adsorbents; Adsorption; adsorption–desorption cycles; amination reagents; Amino groups; Carbon dioxide; CO2 adsorption; Desorption; Diamines; Diethylene triamine; Efficiency; functionalized MCM-48 molecular sieve; Infrared spectroscopy; Investigations; Molecular sieves; Pore size; Porous materials; Reagents; Silica; Silicon dioxide; Structural analysis; Temperature; temperature influence; X ray powder diffraction; X-ray diffraction
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms241210345

The ordered mesoporous silica MCM-48 with cubic Ia3d structure was synthesized using the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) as a template agent and tetraethylorthosilicate (TEOS) as a silica source. The obtained material was first functionalized with (3-glycidyloxypropyl)trimethoxysilane (KH560); further, two types of amination reagents were used: ethylene diamine (N2) and diethylene triamine (N3). The modified amino-functionalized materials were characterized by powder X-ray diffraction (XRD) at low angles, infrared spectroscopy (FT-IR) and nitrogen adsorption–desorption experiments at 77 K. Characterization from a structural point of view reveals that the ordered MCM-48 mesoporous silica has a highly ordered structure and a large surface area (1466.059 m2/g) and pore volume (0.802 cm3/g). The amino-functionalized MCM-48 molecular sieves were tested for CO2 adsorption–desorption properties at different temperatures using thermal program desorption (TPD). Promising results for CO2 adsorption capacities were achieved for MCM-48 sil KH560-N3 at 30 °C. At 30 °C, the MCM-48 sil KH560-N3 sample has an adsorption capacity of 3.17 mmol CO2/g SiO2, and an efficiency of amino groups of 0.58 mmol CO2/mmolNH2. After nine adsorption–desorption cycles, the results suggest that the performance of the MCM-48 sil KH N2 and MCM-48 sil KH N3 adsorbents is relatively stable, presenting a low decrease in the adsorption capacity. The results reported in this paper for the investigated amino-functionalized molecular sieves as absorbents for CO2 can be considered as promising.