Chitosan/agar-agar/TiO2 biopolymer nanocomposite film for solar photocatalysis, antibacterial activity, and food preservation applications

Chitosan/Agar-Agar/TiO 2 ( CS/AA/TiO 2 ) nanocomposite film was synthesized by facile solution casting technique and their formation was validated using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), differential scanning calorimetry (DSC) and UV–visible spectroscopy analysis. The characterization results revealed the thin layers of developed biopolymer nanocomposites and uniform distribution of TiO 2 nanomaterials on the CS/AA surface, and also successful incorporation of TiO 2 materials. The application of CS/AA/TiO 2 nanocomposite film was investigated as a photocatalyst for the degradation of malachite green (MG) dye under direct sunlight, antibacterial activity against gram-positive and gram-negative bacteria and food preservation efficiency. The results demonstrated that the polymeric nanocomposites (CS/AA/TiO 2 ) showed higher MG dye degradation efficiency than the bare polymeric film. The order of photocatalytic activity is CS/AA/TiO 2 (10 mg), 93.10 % > CS/AA/TiO 2 (15 mg), 92 . 50 % > CS/AA/TiO 2 (5 mg), 89.28 % > bare CS/AA (85.71 %) film, respectively. Similarly, the synthesized nanocomposite films demonstrated good antibacterial activity against the E. coli, S. aureus , Pseudomonas sps and Klebsiella sps bacteria. Furthermore, the CS/AA/TiO 2 nanocomposite film showed better food preservation efficiency which significantly increased the shelf life of grapes upto ten days. Hence, it is concluded that the developed biopolymer based nanocomposite films is an efficient solar light responsive photocatalysts, antibacterial and food preservative agents under present experimental conditions. • Chitosan/Agar-Agar/TiO 2 ( CS/AA/TiO 2 ) nanocomposite film was successfully prepared. • CS/AA/TiO 2 nanocomposite film showed effective solar photocatalytic and antibacterial activity. • CS/AA/TiO 2 film exhibited enhanced food preservation, increasing grape shelf life up to 10 days.