AbstractsChemistry

[...] Within recent years silica gel has received considerable attention because of its use as a sorbent, catalyst and catalyst support. The sorption of about fifty materials on silica has been recorded (2). There is an analogy between gelation of silica sols and many physiological functions; such as, deposition of bone and cartilage, formation of mucus, etc. (3). The reverse of gelation, i.e., the peptization of silica gel, is involved in the disease known as silicosis. Gelation is also involved in the setting of concrete and cements, solidification of many minerals, rubber, plastics and foods (e.g. jellies). The structure of a gel when formed might, by analogy, give an insight into the structure of many of these substances. [...] The study of bound water in silica gels should contribute information on the structure of not only silica but other gels. Little is known about the factors governing bound water in gels in general and less is known about bound water in silica gels in particular. A survey of the literature will show some of the factors governing the gelation process and will give an insight into some of the factors that may affect bound water in silica gels. There are no satisfactory theories of gelation and gel structure because of the lack of adequate knowledge in this field. Theories of silica gel structure will not be discussed here as the information is available elsewhere (1). [...]