PRODUCTION OF ACTIVATED CARBONS FROM DIFFERENT TYPES OF CELLULOSE-CONTAINING RAW MATERIALS USING ORTHOPHOSPHORIC ACID

Abstract

Currently, the search for relatively inexpensive raw materials from renewable plant resources to obtain activated carbons based on them remains relevant. The thermochemical destruction of various cellulose-containing plant materials has been studied: pine bark and sawdust, flax tow and cereal straw. The conditions for obtaining activated carbons from them using orthophosphoric acid as an activator have been determined. 68 % concentration of the orthophosphoric acid has been established to be the most optimal for obtaining activated carbons from plant materials by thermochemical activation. It has been shown that under the same conditions of thermochemical synthesis, the characteristics of activated carbons are determined by the chemical composition of the feedstock. According to low-temperature nitrogen adsorptiondesorption data, all the obtained activated carbons have a high specific surface area (1 290–1 380 m2/g) and at the same time contain at least 70 % mesopores with sizes greater than 2 nm and the adsorption capacity relative to methylene blue of 420–610 mg/g. The results obtained allow us to conclude that the method of thermochemical activation of plant materials by orthophosphoric acid makes it possible to obtain mesoporous carbons, which are essentially new sorbents exhibiting high efficiency in adsorption processes.