Process Intensification of Mesoporous Material’s Synthesis by Microwave-Assisted Surfactant Removal

Mesoporous materials are of vital importance for use in separation, adsorption, and catalysis. The first step in their preparation consists of synthesizing an organic–inorganic hybrid in which a structuring directing agent (SDA, normally a surfactant) is used to provide the desired porosity. The most common method to eliminate the SDA, and generate the porosity, is high-temperature calcination. Such a process is energy-intensive and slow. In this study, we investigated alternative nonthermal surfactant removal methods on a soft MCM-41 material, aiming at reducing the processing time and temperature, while maximizing the material’s properties. The choice of a soft MCM-41 is critical since it is hydrothermally unstable, whereas the SDA removal is troublesome. Microwave processing yielded outstanding performance in terms of surfactant removal, structural preservation, and textural features; the surfactant was fully removed, the hexagonal structure was preserved, and the surface was highly rich in Si–OH groups. It is suggested that H2O2 is the dominant oxidant. In terms of the process features, the processing time is significantly reduced, 14 h (calcination) versus 5 min (microwaves), and the applied temperature is much lower. The energy savings were estimated to be 72% lower as compared to calcination; therefore, this approach contributes to the process intensification of a very relevant material’s production.