PREPARATION OF SILVER-CONTAINING NATURAL ZEOLITES WITH IMPROVED POROUS CHARACTERISTICS AS SORBENTS FOR WATER PURIFICATION

The widespread application of Ukrainian natural zeolites in sorption and catalysis is limited by the shortcomings of their porous structure. Chemical modification of zeolites permits significant changes in their properties. The purpose of this work was to obtain silver-containing natural zeolites of the clinoptilolite type with improved porous characteristics by acid treatment and to study their antibacterial properties. Mild dealumination of the rock was carried out using ethylenediaminetetraacetic acid for 15 hours at 90 °C, which significantly increased the specific surface area of the clinoptilolite sample to 90 m2/g, and the volume of micropores to 0.037 cm3/g, determined by low-temperature nitrogen adsorption/desorption. An establishment of a change in the chemical composition of the sample during processing by X-ray fluorescence analysis was made. Additional modification with silver in the amount of 1 wt % was carried out by impregnation with a solution of silver nitrate. The water of three lakes in Kyiv was studied for the total viable count by means of  sowing in nutrient agar. The results were analyzed and a sample of water was selected to evaluate the effectiveness of the synthesized sorbent. The antibacterial properties of zeolite were confirmed with the worst of the water samples, the quality of which, in terms of the total viable count, was improved not only to the norms of surface water but also to the indicators for drinking water.