Influence of textural and structural properties of Mgsingle bondAl and Mgsingle bondZnsingle bondAl containing hydrotalcite derived oxides on Cr(VI) adsorption capacity

A series of hydrotalcite-like materials containing Mg2+/Zn2+ and Al3+ cations in the brucite-like sheets and carbonate or benzoate anions in the interlayer gallery was prepared by the coprecipitation method. The difference in the chemical composition of the synthesized layered double hydroxides resulted in obtaining mixed metal oxides with various phase composition (caused by different cations) as well as various crystallinity and textural parameters (caused by different anions). The Mgsingle bondZnsingle bondAl oxide systems obtained from the benzoate-intercalated precursors had significantly higher crystallinity and narrower pore size distribution compared to the carbonate-modified samples. The structural and textural properties of the calcined materials influenced their sorption capacities in the chromate removal from an aqueous solution at the optimal pH of 6.0. The most efficient adsorbent was obtained from the calcined magnesium–zinc–aluminum hydrotalcite-like precursor containing interlayer CO32− anions. This material exhibited high efficiency in the chromate elimination even in the presence of competitive anions (Cl− or SO42−).