Alternative Synthesis of MCM-41 Using Inexpensive Precursors for CO2 Capture

We explore the use of industrial sources of silicon and surfactant for obtaining low-cost MCM-41 materials and evaluate their performances as CO₂ adsorbents. All of them presented a high specific surface area with different structural characteristics and textural properties. Interestingly, the MCM-41 manufactured with the most economical reagents presented a S_BET of 1602 m²·g⁻¹. The template was removed by using thermal treatments in an air atmosphere or a washing process. Preservation of silanol groups proved to be more effective under washing or mild thermal treatment conditions with the advantage of their lower cost and environmental benefit. Surface reactivity against CO₂ was enhanced by anchoring APTS to silanol groups through wet grafting. All amino-functionalized materials showed a performance as CO₂ adsorbents comparable to those reported in the literature, reaching values close to 30 cm³·g⁻¹ at 25 °C and 760 mmHg. Samples with a higher concentration of silanol groups showed better performance. Our studies indicate that adsorbed CO₂ is retained at least up to 50 °C, and the CO₂ is chemisorbed on the silica modified with amine groups. The chemisorbed gas at very low pressures points to the potential use of these materials for CO₂ storage.