D. E. Smalchenko, E. N. Titov, O. E. Lebedeva
Belgorod State National Research University (NRU “BelSU”), ul. Pobedy, 85, Belgorod, 308015, Russian Federation
Abstract. The development of new sorption materials based on agricultural waste is a new scientific area. The purpose of the study was to obtain sorption materials from the processing waste (empty calathia) of oilseed sunflower (Helianthus annuus L.), by chemical activation of the feedstock with solutions of nitric, sulfuric, hydrochloric, and orthophosphoric acids at concentrations of 1 M, 3 M, and 10 M, followed by heat treatment in sealed reactors (carbonization) at temperatures varying from 200 C to 650 C. The selected processing method allowed materials to be obtained with a high sorption capacity. The patterns of influence on raw materials of all studied acids were homogenous. The content of total and water-soluble ash in the sorption materials increased with carbonization temperature. Moreover, this tendency persisted when the concentration of the modifier acid varied in the range from 1M to 10 M. The bulk density of the sorption materials increased by 1.5 times with an increase in the carbonization temperature from 200 C to 650 C. The texture of the materials depended on the carbonization temperature – at 350– 500 C we registered the development of internal cavities of the feedstock; at 650 C we registered the destruction of the cellular structure of the plant frame. The pH of the aqueous extract tended to increase with an increase in the concentration of the activator and carbonization temperature. The sorption capacity of the materials was assessed using methylene blue and benzene as sorbates. All the samples obtained were characterized by a developed surface (from 11 m2/g to 110 m2/g for methylene blue and from 306 m2/g to 1,000 m2/g for benzene) and a porous structure providing adsorption in a mixed diffusion mode. The adsorption of methylene blue was described using the most common models (Henry, Langmuir, Freundlich, Dubinin-Astakhov, and Dubinin-Radushkevich models). The most adequate was the Dubinin-Astakhov model.
Keywords: sunflower (Helianthus annuus L.); sorbent; coal; processing; carbonization; agro-industrial complex waste; bulk density; acidity; adsorption.
Author Details: D. E. Smalchenko, assistant (е-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); E. N. Titov, post graduate student; O. E. Lebedeva, D. Sc. (Chem.), prof.
For citation: Smalchenko DE, Titov EN, Lebedeva OE [Obtaining and study of carbon sorbents from oilseed sunflower waste] Dostizheniya nauki i tekhniki APK. 2021;35(8):46-50. Russian. doi: 10.53859/02352451_2021_35_8_46.