ION EXCHANGE his symposium might well be considered a centennial celebration of the discovery and recognition of the phenomenon of ion exchange; for it was almost exactly 100 years ago that J. Thomas Way, consulting chemist to the Royal Agricultural Society of England, discovered that the apparent bodily removal of ammonia from aqueous liquids on passing through certain soils was really an exchange with the calcium of a particular type of silicate occurring in those soils. Furthermore, Way synthesized siliceous base-exchange materials from the same starting compounds that are still used for the purpose; and he developed much of the theory and practice which have furnished the principal guides to industrial applications of ion exchange up to the recent past. Way's prime interest in ion exchange was in its possible application to agriculture. The first attempt, an unsuccessful one, a t industrial application was in sugar technology, the same field which is being explored much more extensively today and, at least in some applications, successfully. I t required some 50 years after Way's discovery for ion exchange to assume any industrial importance. The first decade of the twentieth century marked the beginning of zeolite water softening, a n industry which has grown to such large
of what might be d i e d the modern era of ion exchange came with vent of the sulfonated coal cation exchange materials in the early thirties, t i m d u s was given in 1935 when Adams and Holmes published their [J. Soc. Chern. Ind. (London), 54 (1935)l on purely synthetic organic
(194'01. As a result
