Extraction of Copper(II) Ions with a Sorbent Based on Cellulose and Sodium Alginate Modified with Guanidine

Abstract

A new composite sorbent has been developed based on microcrystalline cellulose and sodium alginate modified with guanidine hydrochloride. Modification was performed via the stage of oxidation of polysaccharides with sodium metaperiodate, forming dialdehyde cellulose and sodium dialdehyde alginate, followed by the addition of guanidine amino groups to the aldehyde groups. A comparative analysis of the sorption properties of the modified sorbent containing amino groups with those of microcrystalline cellulose showed that the sorption efficiency of copper ions depends on the nature of sorption sites. When studying the sorption kinetics of Cu(II) cations, it was found that the results of the kinetic experiment are most correctly described within the framework of the pseudo-second-order model. The experimental isotherms of sorption of copper(II) ions from aqueous solutions with the modified sorbent and microcrystalline cellulose are well described by the Langmuir equation. As a result of linearization of isotherms, it was found that the modified sorbent surpasses microcrystalline cellulose in terms of the maximum sorption capacity by approximately an order of magnitude. The changes in the sorption capacity of the developed sorbent compared to the original are due to the appearance of new sorption sites in its structure, which is confirmed by scanning electron microscopy and IR spectroscopy data.