Poly (Lactic Acid) Grafting of TiO2 Nanoparticles : A Shift in Dye Degradation Performance of TiO2 from UV to Solar Light

Poly lactic acid (PLA) grafting of TiO2 nanoparticles was carried out by in-situ polycondenstion of lactic acid. The synthesized nanocomposite was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), C-13 Nuclear magnetic resonance (NMR), Thermal Gravimetric Analysis (TGA), Xray Photoelectron Spectroscopy (XPS), Transmission Electron Microscope (TEM) etc. Surprisingly, when a chance study of its photocatalytic activity for degradation of two textile dyes viz. methyl orange (MeO) and malachite green (MG) under UV light and solar light, was carried out, it was observed that degradation was faster under sunlight as compared to UV light. In fact, the degradation is fastest reported so far in literature.. Complete decolouration of a 10(-4) M solution of the two dyes under sunlight occurred in 20 and 8 minutes respectively with corresponding first order rate constants of 0.191 and 0.405 min(-1). Further, the photocatalyst showed good recyclabilty and recycled catalyst was also analyzed by FT-IR, XRD, and TEM.