Experimental and statistical investigation of adsorption mechanism of toxic chromium on Al-Fe-Zn oxide nanocomposite and successful application on industrial wastewater.

Present work described the synthesis of Al-Fe-Zn oxide nanocomposite and surface properties determinations by spectrophotometric method. Homogeneous mixing of metals, size range 9–13 nm, and rough surface determined from TEM and FESEM images are discussed. The specific surface area (121.3 m2/g), crystalline nature and elemental composition were deduced from XRD and EDAX analysis. The presence of surface hydroxyl group as identified by FTIR was found responsible for complex formation with chromate ion. The batch adsorption of chromium at different experimental variables revealed an optimised condition for chromium adsorption. Adsorption data followed second-order kinetics, Langmuir, and Freundlich isotherms. The pore diffusion and complex formation for chromium adsorption mechanism were predicted on the basis of kinetic and isotherm studies. The statistical data reveal that the double-layer model best explains the adsorption behaviour and mechanism. The unique surface properties, excellent reuse efficiency signify the application of nanocomposite. [ABSTRACT FROM AUTHOR]