Sorbents based on mesoporous silicas modified with hydrazide functional groups

Abstract

The silica-based sorbents characterized by MCM-41 pore structure and modified with hydrazide groups were synthesized. The low-temperature nitrogen sorption method, X-ray phase analysis, FT-IR spectroscopy and scanning electron microscopy were used to determine textural-structural properties of the silica sorbents under investigation. The presence of modifier reduces values of specific surface area. The impregnation method enhances adsorption capacity to a larger extent as compared with the direct synthesis method. The sorption of copper (II), nickel (II), and cobalt (II) from aqueous solutions by the obtained reagents was studied. The study of non-ferrous cations’ adsorption evinced that, depending on pH value of the medium, both conjoint extraction and separation of cations were possible. The sorbents can be used to quantitatively separate copper (II) ions from nickel (II) ions. The sorption capacity of the reagents as dependent on the method for modification of the silica base and on the monomer concentration was explored under condition of conjoint metal sorption. The effect of temperature on the sorption of metals by the obtained modified silica at different pH values and the method of their interaction with the surface of the MCM were determined.