The process of delumination and the mechanisms of formation of acid centers in clinoptylolite.

Research work consists in studying methods for obtaining highly effective and high-quality sorbents as a result of changing the chemical composition, physico-chemical properties of the mineral by modifying the clinoptilolite mineral by various chemical methods. Study of the mechanisms of formation of two types of strong Bronsted and three types of Lewis acid sites on the surface of clinoptilolite simultaneously with the process of dehydration as a result of acid modification of clinoptilolite. The mechanisms of the stages of dealumination occurring in the crystal lattice of the mineral clinoptilolite are presented, the main structural changes occurring in the process are shown. The energy effect of the clinoptilolite lattice on the separation process shows that the L1 center formed at the first stage of separation corresponds to the L center of aluminum oxide, and the electron-donating ability of the aluminum cation located in the coordination sphere to the second level is much higher than that of the Si +4 cation, due to to this mechanism, the L-centers (L1 and L2) will have to wait for some time until it is generated. The presence of formed L centers indicates that the probability of formation of L centers with the L3 structure is very low. there may be fourth and fifth centers in the system, but the probability of the formation of a fifth type Lewis center is high, and the energy of its formation will have a significantly negative value compared to the fourth type. An increase in the concentration of hydrochloric acid from 3 N to 6 N during the modification of clinoptilolite leads to a significant increase in dealumination, i.e. from 20 to 50%. However, as the acid concentration increases, the crystal lattices of the dealuminated clinoptilolite are sharply distorted. The purpose of this work is to study the mechanisms of the stages of the dealumination process occurring in the crystal lattice of the clinoptilolite mineral and to determine the main structural changes that occur in this process. [ABSTRACT FROM AUTHOR]