Structural, magnetic and adsorption characteristics of magnetically susceptible carbon sorbents based on natural raw materials
Christina Soloviy, Мyroslav Malovanyy, Ihor Bordun, Fedir Іvashchyshyn, Anatoliy Borysiuk, Yuriy Kulyk
Abstract
The article comprises synthesis of magnetically susceptible carbon sorbents based on bio raw materials – beet pulp. The synthesis was performed by one- and two-step methodology using FeCl3 as an activating agent. X-ray diffraction methods showed an increase in the distance between graphene layers to 3.7 Å in biocarbon synthesized by a two-step tech-nique and a slight decrease in inter-graphene distance to 3.55 Å for biocarbon synthesized by an one-step technique. In both magnetically susceptible samples, the Fe3O4 magnetite phase was identified. Biocarbon synthesized by a two-step technique is characterized by a microporous structure in which a significant volume fraction (about 35%) is made by pores of 2.2 and 5 nm radius. In the sample after a one-step synthesis, a significant increase in the fraction of pores with radii from 5 to 30 nm and a decrease in the proportion of pores with radii greater than 30 nm can be detected. Based on the analysis of low-angle X-ray scattering data, it is established that carbon without magnetic activation has the smallest specific area of 212 m2∙сm–3, carbon after one-stage synthesis has a slightly larger area of 280 m2∙сm–3, and after two-stage synthesis has the largest specific surface area in 480 m2∙сm–3. The adsorption isotherms of blue methylene have been studied. Biocarbon ob-tained by two-step synthesis has been shown to have significantly better adsorption properties than other synthesized bio-carbons. Isotherms have been analysed based on the Langmuir model.