Application of bimetallic Al-doped ZnO nano-assembly for heavy metal removal and decontamination of wastewater.

Abstract

In the present study, bimetallic aluminium doped zinc oxide (AZO) nano-assemblies were synthesized for heavy metal removal and disinfection of wastewater. These bimetallic nanoparticles (NPs) were prepared by a simple co-precipitation method and characterized using field emission transmission electron microscopy (FETEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), a Litesizer, and energy dispersive X-ray spectroscopy (EDS). The AZO NPs was tested for lead removal at various environmental conditions and optimized at pH 4 and 25 °C. The kinetic data were well fitted to the pseudo-second-order model and the process consisted of both surface adsorption and intraparticle diffusion. Al doping enhanced the surface charge of AZO NPs four fold as compared to ZnO, which improved colloidal stability and contributed towards its reusability. AZO NPs exhibited excellent removal efficiency of 86% over three adsorption-desorption cycles. The adsorption was found to be an exothermic and physicochemical process. The prepared AZO NPs were also used to treat a real wastewater sample and found to effectively remove Pb(II) and kill all the bacteria present.