PHYSICO-CHEMICAL PROPERTIES OF A COMPOSITE MATERIAL BASED ON CALCIUM HYDROPHOSPHATE AND A SUBSTRATE FROM ASPEN BARK

Abstract

The physicochemical properties of the composite material obtained by sequentially impregnating the substrate from aspen bark with water solutions of KH2PO4 and CaCl2 under certain conditions were studied. Using the method of X-ray phase analysis, it was found that the main products of the interaction of KH2PO4 and CaCl2, which flows from the aspen bark on the substrate surface, are CaHPO4 and KCl. In this case, calcium chloride is present in the obtained composite material in the form of a complex compound CaCl2·Ca(OH)2·H2O. Using IR-spectral analysis, it was revealed that there is no interaction between the functional groups of the aspen bark substrate and mineral compounds during the preparation of the composite material. Based on thermal analysis data, the catalytic effect of the mineral components that make up the developed composite material on the decomposition of hemicellulose, cellulose and lignin that make up the substrate from aspen bark is revealed. It was found that the composite material modified with CaHPO4 is characterized by increased water resistance and after treatment with water at room temperature for 24 hours, 9.85% of phosphates are removed from it (from their initial content). This allows one to use the resulting composite material based on aspen bark as a delayed-action fertilizer.