Synthesis & characterization of Aluminium doped lanthanum oxide nanoparticles for adsorptive removal of Congo red from aqueous solution

Abstract

Aluminium-doped nano lanthanum oxide (ALO NPs) were synthesized using sol–gel method. The structural characterization of the as-prepared nanoparticles were carried out using XRD, FT-IR, SEM-EDAX, HR-TEM, and XPS methods to study the effect of Al doping on the structural properties of lanthanum oxide. XRD analysis confirms the formation of hexagonal ALO NPs with an average crystallite size of 15–20 nm.The FTIR analysis gives an idea about the hygroscopic nature of the Aluminium doped La2O3 and its affinity towards carbon dioxide. SEM images reveal the agglomeration of nanoparticles. HR TEM -SAED characterization provides a deeper understanding of the material's polycrystalline nature. The presence of La in the 3d orbital, O in the 1 s orbital, and Al in the 2p orbital is explained by XPS spectra. The as-prepared ALO-NPs were used as an adsorbent for the removal of the toxic azo dye Congo red from water. The uptake of Congo red was found to increase with an increasing initial dye concentration. A maximum adsorption of 70.03 mgg−1 was obtained for 100 ppm Congo red concentration.