![]() Pore size modifications can significantly improve the sorption capacity ( Palomba and Frazzica, 2019). Their pore size can vary from micro- to mesopores, depending on the chose synthesis conditions, and a specific surface area can be obtained in the range of ~ 100–1000 m 2 g − 1 ( Zhang and Wang, 2020). Silica gel is a well-studied and widely used adsorbent for various applications because of its high affinity with water vapor, its considerable adsorption capacity at low humidity, low cost, and easy regeneration (it can be easily employed with heat sources at temperatures lower than 120 ☌). Silica gels are amorphous forms of silica with chemical composition SiO 2 Kévyn Johannes, in Encyclopedia of Energy Storage, 2022 Silica gel ![]() It is also possible to use sol–gel processing to modify the interior of a fused silica capillary column with a porous organically modified silica gel prepared from TMOS and methyltrimethoxysilane. The resulting monolithic silica gel was surface functionalized, wrapped with a Teflon cladding and used as a HPLC column. More recently the column packing has been prepared as a continuous monolithic structure through sol–gel processing and subsequent calcining at 600 ☌ of a silica-polyethylene oxide nanocomposite. ![]() Silica gels can be used directly as a chromatographic material or after the surface of the particles are chemically modified. Most of these involve the preparation of powders, such as Stöber spheres. Silica gels have long been used for chromatographic applications including flash chromatography in organic synthesis, thin-layer chromatography, and packings for columns used in liquid and gas chromatography. Loy, in Encyclopedia of Physical Science and Technology (Third Edition), 2003 VII.B.1 Sol–Gel Preparation of Bulk Phases for Chromatography ![]()
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