Multifunctionality of Oxide/Hydroxide Systems Based on Magnesium
Доклады на конференциях
Nowadays, magnesium oxide and hydroxide systems obtained by sol-gel (aerogel) method attract more and more attention. These nanosized materials are known to possess unique physicochemical, structural and adsorptive properties different from those of bulk analogues. For example, the reactivity of oxides substantially increases when the dimensions of their particles is decreased down to several nanometers due to the increased ratio of their surface area to the bulk volume and high concentration of various active sites on the surface. At room temperature, these materials are capable of adsorbing acid gases and destroying spores and bacteria. At elevated temperatures nanocrystalline metal oxide aerogels can be used as destructive sorbents for detoxification of halogenated and organophosphorus compounds and as catalysts or catalyst supports. At the same time, magnesium hydroxide is considered as an efficient heat-storage material which is able to store large amounts of heat by reversible chemical reaction. All mentioned above properties can be successfully and controllably varied by doping the pristine MgO or Mg(OH)2 with second component. Sol-gel technique was found to provide uniform distribution of additive in a lattice of magnesia. Concentration of additive can be varied in a wide range starting from ppm level and up to few tens of percent. A simplified method of preparation of two-component systems based on magnesium oxide or hydroxide as well as a progress in their application will be presented and discussed.