Industrially compatible synthesis of MCM-41 with spatial organization at the macro-mesoscale

• Published in: Microporous and mesoporous materials 2024-09, Vol.377, p.113225, Article 113225
• Main Authors: Aquino, Guillermo D., Moreno, M. Sergio, Benedictto, Germán P., Pereyra, Andrea M.
• Format: Article
• Language: English
• Subjects: CO2 adsorption; Industrial sodium silicate; Inexpensive industrial surfactant; Macro-mesostructure; MCM-41
• ISSN: 1387-1811
• DOI: 10.1016/j.micromeso.2024.113225

Nowadays industrial requirements point to high-performance processes but cost-effective materials to maximize their benefit/cost balance. This paper describes the properties of a macro-mesoporous MCM-41 silica with very high surface area obtained from inexpensive reagents —industrial sodium silicate as a source of silicon and industrial CTAC as template— with potential use in an environmental application such as CO2 capture. The MCM-41 silica exhibits an aperiodic 3D hierarchical spatial organization at the macro-mesoscale, formed by well-ordered MCM-41 particles with bowl-like mesopores. These particles are interconnected in three dimensions, creating a web-like structure that imparts macroporosity. This organization can be rationalized in terms of the nature and interaction of the reactants. Thus, the conjunction of poly (N-silicate) and features in CTAC, such as the weakly bonding counterion (Cl−), ethanol and unreacted amine, gave rise to different morphologies and variable channel lengths, porosity at different length scales producing meso/macro arrangements, and a spongy structure as a disordered minority phase. The hierarchical organization enhances the potential of the material for uniform APTS loading, thereby improving CO2 capture. Then the use of industrial reactants offers two important advantages: (i) The presence of macro-mesocavities, enabling applications requiring greater porosity than that intrinsic to MCM-41; (ii) A reduction in production costs by at least 80 % compared to traditional synthesis methods using alkoxysilanes and CTAB, and negligible costs compared to synthesis with analytical grade CTAC. In summary, this study demonstrates the synthesis of a hierarchically structured MCM-41 silica using cost-effective industrial reagents, offering a promising and economical solution for different applications. [Display omitted] •Cost-effective meso/macro MCM-41 silica was synthesized.•Industrial surfactant and silicate solutions produced a distinctive 3D macro-mesostructure.•Particular interactions among components affected growth and assembly.•Production costs were significantly decreased.•APTS/MCM-41 showed high CO2 adsorption and storage capacity.