Effects of substitution of Mg for Zn IN the composition of layered double aluminum hydroxides on their physico-chemical properties

Abstract

Samples of Mg–Zn–Al layered double hydroxide (LDH) have been synthesized by solid-phase interaction of Mg, Zn, and Al crystalline hydrates with (NH4)2CO3, and then studied by chemical, X-ray phase analysis, as well as by Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) methods. The paper presents results of studies of structural and surface properties (specific surface area and volume of pores, distribution of pores by their diameter). It was found that an increase in the degree of substitution of Mg by Zn leads to an increase in the specific surface area and the specific volume of samples. At the same time, the distribution of mesopores has a polymodal character with a predominance of pores having dpor = 3–4 and 25–50 nm. It was found that the substitution of Mg for Zn in the composition of layered double hydroxides leads not only to an increase in the specific capacity of the monomolecular layer of LDH, but also to a stronger interaction of adsorbate (nitrogen) with their surface.