Synthesis and Characterization of Titanium Dioxide (TiO₂) and Zinc Oxide (ZnO) Nanoparticles to Encapsulated Soda Lignin Polymer

This study investigated the lignin utilization as a natural substance to develop environmentally friendly polymeric composites. The soda-pulping technique was used to extract the lignin (called soda lignin (SL)) by employing the NaOH solution to separate the lignin phase from the other biomass. The extracted SL was encapsulated with two different synthesized nanoparticles: titanium dioxide (TiO2) nanoparticles and zinc oxide (ZnO) nanoparticles to form the nanocomposite materials. The structural and morphological properties of prepared SL-ZnO and SL-TiO2 nanocomposites were characterized at room temperature using field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance (1H-NMR). The results revealed that the lignin extraction was easy, safe, and economical as a three-dimensional polymeric aromatic structure. Zinc oxide (ZnO) nanoparticles and a mixture of two phases (Aantase and rutile) of titanium oxide (TiO2) nanoparticles were successfully synthesized by sol-gel and chemical co-precipitation methods, respectively. Finally, the lignin nanocomposites (SL-ZnO and SL-TiO2) were easily and effectively prepared, these nanocomposites were characterized by homogeneous nature and contained compounds with nano-dimensions (i.e. large surface area), the obtained nanocomposites considered an effective candidate as water purification nanocatalysts and environmentally friendly polymer composites.