Investigation of wastes wood processing as adsorbents for wastewater treatment from polychlorobiphenyls

Abstract

Annotation. Waste of plant origin (sawdust, bark, peel, etc.) is a promising material for use as sorbents in the purification of aquatic media from pollutants of various nature. Polychlorinated biphenyls (PCBs) are among the most widespread anthropogenic pollutants in natural and industrial facilities. PCBs have toxic properties and pose a high risk to the environment and public health. The aim of the work was to study the possibility of using sorbents based on natural lignocellulose-containing raw materials (sawdust from pine and linden wood) for use as PCB sorbents in the purification of aqueous media. The concentration of PCBs in aqueous solutions before and after sorption was determined by gas chromatography with flame ionization detection. The sorbents studied showed high efficiency in the extraction of a PCB mixture: the maximum sorption capacity at an initial PCB concentration of 50 mg/dm3 for a sorbent based on pine sawdust is 2500 mg/g, for a sorbent based on linden sawdust – 2384 mg/g. It is shown that the highest degree of PCB recovery is achieved by adding 20 g/dm3 of sawdust with a particle size of 0.75-2.00 mm. Complete recovery of PCBs is observed in 4 days when using pine sawdust, while when using sawdust from linden wood, even after 14 days, the recovery rate is only 94%. Sorption kinetics has been studied and it has been established that the kinetic parameters of sorption correspond to the pseudo-second-order model. The adsorption isotherms were processed using the Langmuir, Freundlich, Temkin, and Dubinin-Radradkevich models. It is shown that for both sorbents, the sorption process is best described by the Langmuir model. The parameter values calculated on the basis of the values of the equation constants these models indicated a high degree of adsorbate affinity to the surface of the adsorbents under study, the PCB sorption process is not spontaneous with the formation of a monolayer structure and mainly physical sorption of PCB molecules on the surface of sorbents takes place. © 2025, Voronezh State University. All rights reserved.