Effective Removal of Methylene Blue by Surface Alteration of TiO2 with Ficus Carica Leaf Extract under Visible Light

Abstract

The present study describes the use of a leaf extract from Ficus carica as a source of natural antioxidants for the surface alteration of bulk titanium dioxide (TiO2) in two steps. First, the hydro-thermal treatment of the bulk TiO2 material was carried out and followed by thermal annealing at 300 °C for 3 h in air. The role of the leaf extract of Ficus carica on the performance of the bulk TiO2 material for the removal of methylene blue (MB) was also studied. Various analytical techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were used to explore the crystalline structure, morphology, and composition. The bulk TiO2 material after the leaf-extract treatment exhibited mixed anatase and rutile phases, a flower-like morphology, and Ti, O, and C were its main elements. The average crystallite size was also calculated, and the obtained values for the bulk TiO2 material, 18.11 nm, and the treated bulk TiO2 material with various amounts, 5, 10, and 15 mL, of leaf extract were 16.4, 13.16, and 10.29 nm respectively. Moreover, Fourier-transform infrared spectroscopy validated the typical metal–oxygen bonds and strengthened the XRD results. The bulk TiO2 material chemically treated with Ficus carica has shown outstanding activity towards the degradation of MB under sunlight. The 15 mL of Ficus carica extract significantly enhanced the photocatalytic activity of the bulk TiO2 material towards the degradation of MB. The dye degradation efficiency was found to be 98.8%, which was experimentally proven by the Fourier Transform Infrared spectroscopoyy (FTIR) analysis. The obtained performance of the bulk TiO2 material with Ficus carica revealed excellent surface modifying properties for poorly-performing photocatalysts towards the degradation of synthetic dyes when used in their pristine form. The presented approach suggests that Ficus carica could be of great interest for tuning the surface properties of materials, either in the form of nano-size or bulk-phase in a particular application.