Study of heteroaggregation and properties of sol-gel AlOOH–Fe(3)O(4) composites

In this work, AlOOH–Fe(3)O(4) powder nanocomposites for Cr(VI) adsorption were obtained for the first time using oppositely charged boehmite and citric acid modified magnetite sols. The process of heteroaggregation of oppositely charged AlOOH and Fe(3)O(4) nanoparticles was also studied as one of the stages in the preparation of adsorption active material. Сomposition, surface area, porous structure, thermal and surface properties, adsorption efficiency, and regenerability of nanocomposites were investigated using a wide range of analytical methods. It is noted that a low content of magnetite (2 wt.%) in the AlOOH–Fe(3)O(4) composite promotes an increase in the surface area, weakly affects the Cr(VI) adsorption capacity, and imparts magnetic properties to the composite. Low cost, simplicity of preparation, high Cr(VI) adsorption capacity (up to 21 mg/g), and stability in cyclic use are the advantages of the obtained nanocomposites in comparison with similar systems. They can easily be separated from the purified liquid using a permanent magnet due to their magnetic properties.