STUDY OF FORMALDEHYDE ADSORPTION BY COMPOSITE SORBENTS BASED ON LIGNITE AND MANGANESE OXIDE
The relevance of the work is determined by the fact that the adsorption of various organic compounds is an important task associated with the purification of drinking water, as well as industrial wastewater. The aim of this work is devoted to the study of the formaldehyde sorption process from aqueous solutions by the composite sorbent based on lignite with manganese oxide particles deposited on the surface. The set of the obtained analytical data shows that, the sorbent prepared in this work was more efficient than a high-porous carbon sorbent obtained by alkaline activation of grade D coal despite relatively small values of textural characteristics. The adsorption isotherm of formaldehyde by the carbon sorbent with manganese oxide located on the surface can be described by the Freundlich equation (R<sup>2</sup> ≈ 0.997). The sorption of formaldehyde in the investigated range of equilibrium concentrations on the prepared sorbent presumably occurs at low degrees of surface coverage. Analyzing the porous structure of the prepared sorbents and the analytical data of the formaldehyde adsorption from water, it can be assumed that these sorbents can be used for the purification of waste water from formaldehyde