Theoretical and Experimental Assessment of Azo Functionalized Iron Oxide Nanoparticles as Semiconductor Material for Adsorbent Interest

Abstract

The application of magnetic nanoparticles as one of the remedies to remove pollutants in water resources has become very alluring due to their adsorption capacity, magnetic property, and biocompatibility. However, one of the drawbacks is the stabilization of nanoparticles will undergo agglomeration and oxidation by air, which results in the loss the magnetism and limits their applicability. In conjunction with the matters stated, this present study focuses on the conjugated π-systems of azo moiety (-N=N-) as a coating agent to be incorporated in magnetite nanoparticle (MNP) linkage namely azo functionalized magnetic nanoparticles (MNP@Azo). By considering its hydrophobic properties and conjugated π-system, it can be examined as ideal functionalization material. The assessment of MNP@Azo adsorbent has been physicochemically characterized via selected spectroscopic and analytical methods namely infrared (IR), UV-visible (UV-vis), 1D Nuclear Magnetic Resonance (NMR), and thermogravimetric (TGA) analysis. The experimental and simulated UV-Vis absorption spectra were compared using Gaussian 09 software employing the density functional theory (DFT) approach with a set of basis functions B3LYP/6-31G (d,p). According to the findings, DFT calculation proved that the value of energy separation between HOMO and LUMO exhibits semiconductor properties at 3.64 eV. Furthermore, SEM analysis revealed that MNP@Azo is spherical in shape. From the preliminary test, the synthesized azo functionalized nanoparticle (MNP@Azo) was utilized as the adsorbent for the adsorption of polycyclic aromatic hydrocarbon (PAH), mainly pyrene from aqueous solution. According to the results, synthesized MNP@Azo could remove 89.49% of pyrene from the water sample. In conclusion, this newly fabricated adsorbent is applicable to act as an adsorbent for water treatment.