TiO2 (rutile) embedded inulin—A versatile bio-nanocomposite for photocatalytic degradation of methylene blue

•A versatile biopolymer–Inulin was extracted from Allium Sativum L. (Garlic) by adopting a simple route.•Reinforcement of the properties of both inulin and TiO2 was achieved by embedding TiO2 onto the extracted inulin.•Enhanced photo catalytic activity was exhibited by Inulin-TiO2 compared to Pristine TiO2.•A simple approach to eco-toxicity minimization through degradation of harmful dyes was proposed. Inulin, a water soluble carbohydrate polymer, was extracted from Allium sativum L. by hot water diffusion method. A novel bio-nanocomposite was prepared by embedding TiO2 (rutile) onto the inulin matrix. The extracted inulin and the prepared bio-nanocomposite were characterized using UV–vis, FT-IR, XRD, SEM, TEM and TGA techniques. The photocatalytic activity of the bio-nanocomposite for the degradation of methylene blue was studied under UV illumination in batch mode experiment and was found to be twice as high as that of pristine TiO2. The kapp for inulin–TiO2 (0.0449min−1) was higher than that for TiO2 (0.0325min−1) which may be due to the synergistic action of inulin and TiO2. The stabilization of photo excited electron suppressed the electron–hole pair recombination thereby inducing the electrons and the holes to participate in the photo reduction and oxidation processes, respectively and enhancing the photocatalytic activity.