Abstract:modified sorption materials based on acacia sawdust (Acacia Auriculiformis) were obtained by treating their surface with low-concentration sulfuric acid solutions with concentrations of 1%, 2% and 3%. According to IR spectra, diffractograms, micrographs and histograms of the distribution of surface roughness of native and sulfuric acid-modified acacia sawdust, it was found that surface treatment of the sawdust with acid solutions leads to a change in the structure of the sorption material, namely, leaching of low molecular weight components from the composition of acacia wood. The regularities of the processes of adsorption of Cu2+ ions by native and sulfuric acid modified acacia filings under static conditions were studied. Using the obtained values of the initial and equilibrium concentrations of copper (II) ions in solutions, the sorption capacities of the materials were calculated and the adsorption isotherms of Cu2+ ions were constructed using native and modified acacia filings. Processing acacia sawdust with sulfuric acid solutions leads to an increase in the sorption capacity for copper ions, while the greatest sorption capacity is observed in the case of acacia sawdust treated with a 3% sulfuric acid solution. By processing the obtained sorption isotherms in the framework of the monomolecular models of Langmuir, Freindlich, Dubinin-Radushkevich, Temkin, the regression equations and approximation coefficients are determined. It was revealed that the processes of adsorption of Cu2+ ions by native and modified acacia sawdust with a 3% sulfuric acid solution are best described by the Langmuir model, and the processes of copper ion adsorption by acacia sawdust modified by 1% and 2% sulfuric acid solutions are described by the Freindlich model. The thermodynamic constants of the adsorption processes are calculated, from the values of which it is determined that all the studied processes belong to the processes of physical adsorption. By processing the kinetic dependences of the processes within the framework of the diffusion adsorption model, we calculated the Bio coefficients for the sorption processes of Cu2+ ions by native and modified acacia filings, the values of which determined the limiting stages of the processes (mixed diffusion).

Keywords: modification, copper (II) ions, Acacia auriculiformis filings, adsorption models, thermodynamics, kinetics, adsorption