Biochar-Supported Titanium Oxide for the Photocatalytic Treatment of Orange II Sodium Salt

Recent improvements in advanced technology for toxic chemical remediation have involved the application of titanium oxide nanoparticles as a photocatalyst. However, the large energy bandgap associated with titanium oxide nanoparticles (3.0–3.20 eV) is a limitation for their application as a photocatalyst within the solar spectrum. Various structural modification methods have led to significant reductions in the energy bandgap but not without their disadvantages, such as electron recombination. In the current investigation, biochar was made from the leaves of an invasive plant (Acacia saligna) and subsequently applied as a support in the synthesis of titanium oxide nanoparticles. The characterization of biochar-supported titanium oxide nanoparticles was performed using scanning electron microscopy, Fourier transformer infrared, X-ray diffraction, and Brunauer–Emmett–Teller analyses. The results showed that the titanium oxide was successfully immobilized on the biochar’s external surface. The synthesized biochar-supported titanium oxide nanoparticles exhibited the phenomenon of small hysteresis, which represents the typical type IV isotherm attributed to mesoporous materials with low porosity. Meanwhile, X-ray diffraction analysis revealed the presence of a mixture of rutile and anatase crystalline phase titanium oxide. The synthesis of biochar-supported titanium oxide nanoparticles was highly efficient in the degradation of Orange II Sodium dye under solar irradiation. Moreover, 83.5% degradation was achieved when the biochar-supported titanium oxide nanoparticles were used as photocatalysts in comparison with the reference titanium oxide, which only achieved 20% degradation.