Efficient removal of arsenic(V) from water using iron-containing nanocomposites based on kaolinite

Abstract

We studied the main physicochemical features of removing of arsenate from contaminated waters utilizing stabilized nanoscale iron. An inorganic kaolinite matrix was used for stabilization. The structure of adsorbents was studied using some physicochemical methods (X-ray powder diffraction and the low-temperature N2 adsorption-desorption method). It was found that the efficiency of the removal of arsenic (V) ions depends on the weight ratio of iron nanopowder to kaolinite, whereas it does not depend on the pH of the water systems in a wide range. Kinetics data were analyzed using pseudo-first-order and pseudo-second-order models. It was stated that the removal of arsenic by iron-containing composites based on kaolinite occurs relatively rapid. The adsorption kinetic was appropriately described by the pseudo-second-order model, indicating the high affinity of arsenates with the surface of the iron-containing nanocomposite. The results demonstrated that the obtained materials have a much higher sorption capacity to As(V) ions than natural silicates. The Langmuir and Freundlich isotherm equations provided good fittings for the experimental sorption data. It was shown that the sorbents based on stabilized nanoscale iron effectively remove toxic arsenic ions from contaminated water.

Synthesis and characterization of kaolinite-based granular adsorbents for the removal of Cu(II), Cd(II), Co(II), Zn(II), and Cr(VI) from contaminated water

“…Most often, in the synthesis of oxidation-resistant iron-containing adsorbents, such available aluminosilicates as montmorillonite and kaolinite are used. With their help, wastewater is purified, both from cationic forms of metals and anions [11]. It should be noted that in the cited scientific works the authors investigated the effectiveness of composite adsorbents to remove inorganic toxicants from solutions that contained any one metal ion.…”