Abstract
Natural zeolite clinoptilolite has long been successfully used for water purification from heavy metals and ammonia, but phillipsite has a higher ion-exchange capacity and is more promising to use in this area. This paper considers the chemical composition, structure and properties of natural Georgian phillipsites and their modification by the ion exchange. X-ray diffraction patterns and infrared spectra confirm the preservation of the zeolite structure during ion- exchange reactions carried out in solutions and in the solid state. The ion exchange capacity of phillipsites in relation to different ions is in the range of 1.5-3.3 meq/g, they have high selectivity towards ammonia, but the selectivity series depend on zeolite origin: K+>NH4+ for phillipsites from the Akhaltsikhe deposit, and NH4+ >K+ for phillipsites from the Shukhuti manifestation characterized by high content of potassium. The degree of substitution with heavy metal (Cu, Co, Pb) ions in the reactions in solutions is about 80%; by means of reactions in the solid state, phillipsites enriched with biocidal metals (Ag, Cu, Zn), exhibiting bacteriostatic activity against Escherichia coli, have been prepared. The results obtained allow us to conclude that Georgian natural phillipsites, in particular the samples from Shukhuti, can be successfully used for water purification as filtering materials with a surface protected from bacterial contamination.