Effective adsorptive removal of azo dyes over spherical ZnO nanoparticles

In this study, we describe a nanostructured ZnO adsorbent, which displays remarkable efficiency toward the removal of widely used azo dyes, methyl orange (MO) and amaranth (AM), from aqueous systems. The ZnO nanoparticles (ZnO-NPs) were prepared by simple co-precipitation method, and the structural morphology of the as-prepared NPs was revealed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform IR (FTIR) and Brunauer–Emmett–Teller (BET). After complementary characterization, as-prepared ZnO-NPs were further used as adsorbent for the removal of toxic azo dyes (MO and AM) from water. The results revealed that an amount of 0.3 g ZnO-NPs showed maximum removal efficiency of each dye (40 ppm) at pH 6. It was further confirmed that the adsorption of both dyes on ZnO-NPs strongly followed the Langmuir model whereas the kinetics studies revealed that each adsorption process was pseudo second order. Moreover, the findings suggested that R-SO3– groups were active sites and the electrostatic attraction between the dyes (MO–, AM–) and ZnO-NPs+ may be the prime adsorption mechanism of designated removal systems.Graphical abstract
Source: Journal of Materials Research and Technology - Category: Materials Science Source Type: research