An ion-exchange is an established unit operation and is an important supplement to procedures such as filtration, distillation and adsorption. In the laboratories, ion-exchangers are used as an aid in analytical and preparative chemistry. However, the most important application is still the purification and demineralization of water, a perennial challenge since the time of Aristotle and Moses and a task which the growth of population and industries has made even more pressing than ever before. The inorganic ion-exchangers exhibit high selectivities for specific ions resulting in the...