Nanocomposite Based on Natural Zeolite Containing Hydrated Iron (III) Oxide for Removal of Heavy Metal Ions from Water

Abstract

The theoretical approach, which allows us to control the formation of aggregates incorporated into porous matrixes has been developed and verified. The important parameter is the pH of a precipitator: the higher this value, the larger aggregates are formed. Based on the approach, a method of obtaining the composite based on natural clinoptilolite-based zeolite containing nanoparticles of hydrated iron oxide has been developed. The sorbents were investigated using XRD, TEM, SEM and porometric methods. Weakly basic precipitator has been recommended in order to obtain the nanosized aggregates of the modifier. During the synthesis, porous structure of the zeolite substrate is transformed: highly ordered pores, a radius of which is 1–2 nm are unblocked. This is due to dissolution of the additions of clay minerals, which are different from clinoptilolite, Sorption of di- and trivalent cations from multicomponent solution was studied. The zeolite modifying improves sorption of metals, which are not related to d-elements. As found, the removal degree of Pb <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions reaches 97%. The isotherm of Pb <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> sorption are fitted with Freundlich model. In addition to the lead extraction from aqueous solutions, the sorbent could be also recommended for water softening.