NANOPOROSITY STRUCTURE OF NATURAL ZEOLITE FROM THE BIGADIC/BALIKESIR DEPOSIT (TURKEY)
In order to identify phases presented in the studied zeolite, the analysis of X-ray diffractograms was carried out. The presence of clinoptilolite, aluminosilicate, and in smaller amounts of quartz was observed in the zeolite samples. Thermogravimetric studies showed that relative weight losses of samples correspond to desorption of the physical adsorbed water from grain surface and from macropores, to desorption of the weakly bound zeolite water from mesopores, and to desorption of strongly bound (firmly bound) zeolite water. The samples were investigated by low-temperature nitrogen adsorption. Nitrogen adsorption-desorption isotherms (77.4 K) were obtained, from which numerical values of the specific adsorption surface (SBET) were determined by the Brunauer-Emmet-Teller (BET) method. The average pore size has been calculated by the Barrett-Joiner-Halenda (BJH) method. It has been established that the samples contain a porous system consisting almost exclusively of mesopores. The presence of a small number of macro pores with a pore size of about 300 nm was also shown. The average pore size in the texture of the studied samples is 19.6 nm. It is concluded that the insignificant porosity of the material and the large size of mesopores restricts its use as a carrier sorbent as part of an immobilized preparation for the production of organomineral fertilizers.