Periodic mesoporous organic–inorganic hybrid materials: Applications in membrane separations and adsorption

This review discusses the state of the art on the synthesis, functionalization and emerging applications of mesoporous silica materials. Mesoporous silica materials can be synthesized as membranes or powders with controlled pore size and geometry depending on the synthesis conditions. Mesoporous membranes are generally grown on porous supports by solvent evaporation or hydrothermal synthesis techniques. Synthesis of powdered mesoporous silica materials with controlled pore sizes in the range 2–30 nm and various different pore geometries has been an active area of research over last 15 years. Functionalization of the pore channels of ordered mesoporous silica with organic groups provides new opportunities for fine-tuning the chemical, physical, mechanical, and dielectric properties of these intriguing materials. This has led to an interest in application of these materials as separation membranes for the removal of environmental pollutants, e.g. greenhouse CO2 emissions, and the separation of bioethanol from water; heterogeneous catalysts; adsorbents for removal of environmental pollutants, such as Hg; as well as other advanced nanotechnological applications.