Design and synthesis of polyvinyl alcohol derived conjugated polyene modified TiO2 for visible-light degradation of chloramphenicol

Visible-light active conjugated polyene modified TiO2 (CPE-TiO2) nanocomposite was prepared by a facile homogenized sol-gel procedure. After synthesis, the materials were appropriately characterized and used in visible light photodegradation of chloramphenicol (CAP) using LED-light as a source of irradiation. The results indicated that the UV-vis DRS spectra of the CPE-TiO2 with a lower band-gap showed a better absorption ability in the wavelength range of 400 - 800 nm. This result was further confirmed by photoluminescence analysis, which indicated a less recombination rate of electron/hole pairs. Notably, CPE-TiO2 nanocomposite exhibited higher photocatalytic properties as compared to pure TiO2 under visible light. For the photocatalytic degradation of CAP using CPE-TiO2, the results showed a significant improvement in degradation efficiency (80.47 %) as compared to pure TiO2 (36.12 %) at the optimum pH of 7 and most of this antibiotic was degraded within 210 min of visible light irradiation. Co-existence of multiple bonds in poly-conjugated carbon chain with a reduced band gap in CPE-TiO2 composite was able to enhance charge separation and migration as well as improve photocatalytic efficiency.