Вісник Черкаського державного технологічного університету (Jan 2020)
MODIFICATION OF THERMALLY ACTIVATED NATURAL CLINOPTILOLITHE WITH SILVER IONS
Abstract
The analysis of the areas of application of natural zeolite – clinoptilolite is carried out. In particular, it is used as a sorbent with cation-exchange properties in the purification of natural and waste waters from non-ferrous and heavy metals, radionuclides and other harmful components of water. The prospects of modifying clinoptilolite with silver ions are shown. These ions give it antibacterial properties, which significantly expands the scope of its application. The scheme, as well as a description of laboratory unit and the methodology for carrying out studies related to dehydration as thermal activation and modification of natural clinoptilolite with silver ions, are presented. The results of zeolite dehydration in the temperature range of 100 ... 400 °C, as well as due to the action of electromagnetic radiation of the microwave range, are presented and analyzed. The speed of the process and the degree of thermal and electromagnetic dehydration of clinoptilolite are determined. It is shown that, under the influence of electromagnetic oscillations, the degree of dehydration corresponds to thermal activation at a temperature of 120 °C, however, the temperature of the mineral rises at this by no more than 2 degrees. It is found that thermal activation contributes to an increase in the sorption capacity of clinoptilolite relative to silver ions. An increase in the activation temperature leads to an increase in the rate of ion exchange, however, in the range of dehydration temperatures of 150 ... 400 °C, the equilibrium capacity of zeolite with respect to silver ions is almost the same. An increase in the temperature of modification has little effect on the rate and degree of substitution of the exchange zeolite cations with silver ions. This indicates that the modification process takes place in the intradiffusion region. The features of ion exchange in the case of initial and thermally activated samples of clinoptilolite are analyzed.
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