Examining dye degradation and antibacterial properties of organically induced α-MoO3 nanoparticles, their uptake and phytotoxicity in rice seedlings

Abstract A thermodynamically stable, organically induced α-MoO3 nanoparticles (NPs) consisting of orthorhombic units were synthesized and investigated for its photocatalytic activity in presence of visible light and for antibacterial properties. The XRD studies confirmed the formation of crystalline α-MoO3-NPs. HRTEM revealed its sheet morphology with 21.34 nm of crystallite size. The α-MoO3-NPs had dual optical band gap of 1.67 eV and 2.22 eV in UV Diffuse Reflectance Spectra (UV-DRS). In presence of LED light (12 W) and absence of an oxidizing agent the exhibits strong photocatalytic degradation of both cationic (Methylene Blue) and anionic (Eosin Yellow) dyes with 99% and 94% removal efficiency, respectively. The α-MoO3-NPs exhibit antibacterial activity towards microorganisms of health importance viz. Gram positive (B. cereus) and Gram negative (E. coli) at low concentration of 100 mg/l. Uptake, translocation and bioaccumulation of α-MoO3-NPs when studied in rice seedling cv HUR3022 at 15 days of growth revealed the uptake of Mo be 7.3 ppm in roots and 4.5 ppm in shoots under 100 mg/l α-MoO3-NPs treatment. More translocation of Mo from root to shoot upon application of organically induced α-MoO3-NPs were noted however, the translocation factor was 0.6, almost similar to that in controls. The translocation and bioaccumulation factor both were below 1.0 suggesting novel α-MoO3-NPs to be non-phytotoxic and environmentally safe. The synthesized α-MoO3-NPs via simple steps and their remarkable photocatalytic properties, reusability, antibacterial activity and safe for environment makes them a promising nanomaterial for varied applications including membrane technology, water treatment, control of bacterial infections and in agriculture.