Dehydration of Amorphous Calcium Monodiphosphate at Room Temperature

This article presents the results of a study of the dehydration of precipitated amorphous calcium monodiphosphate in air at room temperature. A compound with a molar ratio of diphosphate to monophosphate of about ۳:۷, an atomic ratio of P/Ca of about ۰.۵, and a water content of about ۸۰% was obtained. The high rate of water absorption by phosphate proves that most of the pores in the substance are open. Dehydration leads to a change in the state of chemical bonds in phosphate anions and, apparently, in H۲O molecules. During dehydration, the state of the P-O and O-H chemical bonds changes noticeably. Obviously, in the final stages of dehydration, conditions are created in the substance that favor the entry of gases and vapors from the air, and this is possible if pores are formed there. Dehydration occurs in four stages with the formation of intermediate phases containing different amounts of water and differing in the state of the P-O chemical bonds. The remaining moisture is lost by the substance upon heating in three stages. In this case, the phosphate also changes at the level of chemical bonds. The scientific novelty of the study lies in the fact that the patterns of dehydration of amorphous calcium monodiphosphate at room temperature have been established, and the relationship between the change in chemical bonds and the formation of an open porous structure has been revealed. The practical significance of the obtained results lies in the fact that the formed material can be considered a promising sorbent and carrier for biologically active substances, as well as a model for studying the processes occurring in phosphate biominerals.

کلیدواژه ها:

Amorphous phosphates ، Amorphous Calcium Monodiphosphate ، Dehydration ، Thermal Analysis ، Sorbents