PROCESS FOR FABRICATION OF MULTIFUNCTIONAL COMPOSITE MATERIALS BASED ON BIOCARCOAL, HYDROCYAPATITE, AND NITROGEN-DOPPENED TITANIUM DIOXIDE, AND MATERIALS OBTAINED FROM THIS PROCESS

Abstract

The invention proposes a process for the fabrication of a multifunctional composite material, comprising the following steps: (i) the fabrication of biochar from plant biomass, such as from agriculture and / or forestry, by pyrolysis in an inert atmosphere at temperatures between 550°C and 650°C, where the source biomass may include sugarcane bagasse as a preferred option; (ii) the synthesis of hydroxyapatite by dissolving calcium phosphate and / or apatite ore in an inorganic acid solution, filtering out insoluble residue; (iii) the preparation of nitrogen-doped titanium dioxide sol solutions by a controlled sol-gel method at low temperatures between 0°C and 4°C;and (iv) synthesize a multifunctional composite material by mixing biochar and a hydroxyapatite-containing solution, then adjusting the pH of the mixture to a value between 9 and 10 to create a hydroxyapatite matrix on biochar, then impregnating this matrix with a nitrogen-doped titanium dioxide sol solution, drying and heat-treating the resulting mixture in an inert atmosphere at a temperature between 400°C and 500°C for 1 to 3 hours to form a crystalline nitrogen-doped titanium dioxide phase on the biochar / hydroxyapatite matrix, obtaining a finished multifunctional composite material. In addition, the invention proposes a multifunctional composite material, superior to that obtained from the above process, in which the material has a porous, multiphase heterostructure with the constituent phases in surface contact with each other.