Magnesiumoxide nanostructures were synthesized via a sol-gel combustion method using urea, oxalic acid, and
citric acid fuels. The effect of the fuel type on the products was studied. The as-prepared products were characterized
by means of FE-SEM, HR-TEM, XRD, and FT-IR analyses. The results exhibited that the used fuels gave
MgO products with different morphologies, and the oxalic acid fuel produced pure MgO nanoparticles with the
smallest crystallite size (ca. 12 nm). The adsorption properties of the MgO products for the removal of Reactive
Red 195 (RR195) and Orange G (OG) anionic dyeswere examined. Using a batch method, various parameters affecting
the adsorption properties were studied. The results revealed that MgO nanostructure generated fromthe
oxalic acid fuel had the highest adsorption capacities (207 and 21.5 mg/g for RR195 and OG dyes, respectively).
Additionally, the adsorption data followed the pseudo-second-order kineticmodel and Langmuir adsorption isotherm
model. And the adsorption process was controlled by intra-particle diffusion, bulk diffusion, and film diffusion
mechanisms. Besides, the thermodynamic study showed that the adsorption of the textile dyes of interest
on the as-prepared MgO nanostructures was an exothermic, physisorption and spontaneous process. |
