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We report the synthesis of Ag/bentonite, ZnO/bentonite and Ag/ZnO/bentonite nanocomposites (NCs) using Hagenia abyssinica plant extract and their antibacterial study. The synthesized NCs were characterized by using many advanced techniques. The X-ray diffraction and high resolution transmission electron microscopy analysis confirmed the formation of composites with different phases. The average crystallite size (D) values of pure Ag nanoparticles (NPs), ZnO NPs, and activated bentonite (Na-AB) were found to be 8.14, 18.1, and 37.6 nm, respectively. The Ag/bentonite NCs, ZnO/bentonite NCs, and Ag/ZnO/bentonite NCs exhibited the D values of 7.4, 9.4, and 9.4 nm, respectively. The Fourier transform infrared spectral analysis revealed the presence of hydroxyl, carbonyl, and other functional groups on the surface of the synthesized NCs. The transmission electron microscopic analysis revealed the formation of Ag and ZnO NPs with hexagonal, rod-shaped, and spherical structures. HRTEM also revealed the presence of (102) plane of ZnO and (220) plane of Ag in Ag/ZnO/bentonite NCs. The antibacterial activities of the composites suspension were evaluated against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 by the disc diffusion and broth dilution methods. The ternary NC and Ag/ZnO/bentonite exhibited better zone of inhibition of 14.3 ± 0.3 and 17.3 ± 0.2 mm at 10 mg·mL−1 toward E. coli and S. aureus bacterial strains. The minimum inhibitory concentration and minimum bactericidal concentration values of Ag/ZnO/bentonite NCs were found to be 156.25 and 312.5 µg·mL−1 for E. coli. The investigation results revealed that the low temperature bio-synthesized Ag/ZnO/bentonite is a promising bactericide over the binary composites.

The application of flexible polymer nanocomposites for food packaging to inactivate microorganisms associated with foods is the demand of the present-day food industry to assure quality throughout the packaging operation. The utilization of polyvinyl alcohol (PVA) assisted zinc oxide nanocomposite for food stuff packaging has been very attractive in the recent past. Nanostructured ZnO was synthesized at optimized pH (10.5) from different ratios of zinc acetate and Moringa oleifeira leaf extract (1:7, 1:3, 1:1 and 3:1). ZnO coated polyvinyl alcohol (ZnO/PVA) nanocomposites were prepared from 5, 9, 13 and 16% by wt of ZnO and PVA using solution casting method. The thermal stability of ZnO synthesized with 1:1 ratio at pH 10.5 was investigated with TGA/DTA. The analytical techniques such as X-ray diffraction (XRD), ultra-violate visible analysis (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) were used for the characterization of the synthesized ZnO and ZnO/PVA nanocomposites (NCs). The antibacterial activity of the synthesized ZnO and ZnO/PVA NCs were evaluated against gram negative E. coli and gram positive S. aureus bacteria. The electrochemical stability of ZnO/PVA NCs was also investigated by cyclic voltammetric (CV) method. The thermogram of ZnO indicated that the oxide was found to be stable even beyond 500°C. The SEM analysis revealed rod shaped morphology for synthesized ZnO from 1:1 ratio at pH 10.5. But the nanocomposite prepared with 5% of ZnO of (1:1) at the same pH exhibited uniformly dispersed rod-shaped particle on the surface as well as in matrix of polyvinyl alcohol film. According to XRD result, ZnO synthesized with more percentage of plant extract resulted in the small size crystallites while that with low percentage of plant extract resulted in the larger crystallite size. The antibacterial inhibition efficiency of ZnO/PVA NCs was better and found to increase with increase in the amount of ZnO.

A series of MgAl2O4: Sm3+ nanophosphors were synthesized using oxalyl dihydrazide (ODH) as fuel at low temperature. The X-ray diffraction studies revealed a crystallite size of 20 nm for the nanophosphors. The energy band gap values were found to be in the range from 4.86 to 5.42 eV. Because of distinct f–f transitions from 4F7/2 ⟶ 6P3/2 of Sm3+ ions in the host stimulated at 406 nm, the PL characteristic emission peaks of Sm3+ ions were observed between 406 and 605 nm. The optimized MgAl2O4: Sm3+ phosphors exhibited 97% colour purity and lie in the orange red to yellow area of the CIE diagram. With MgAl2O4: Sm3+ nanophosphors, novel photocatalysts for the elimination of the dye Fast orange red (FOR) have been proved to function at an excited wavelength of 493 nm in UV light. The experiment showed 97.46% dye decolorization, respectively, after 120 min irradiation. Using the carbon paste electrode in the cyclic voltammetry (CV) technique, lead was detected in 0.1N HCl solution (MCPE). The MgAl2O4: Sm3+ nanophosphors are useful sensing material for an element like lead. Finally, we conclude that the synthesized MgAl2O4: Sm3+ nanophosphors are potential candidates for multifunctional applications. [ABSTRACT FROM AUTHOR]

This present research aimed to investigate the novel applications of synthesized La doped CuFe2O4 nanomaterial (LCF NMs) using renewable bio-fuel (Aegle Marmelos extract) by combustion process. The sensor applications were accomplished by modified electrode using LCF NMs with graphite powder and examined its excellent sensing action towards heavy metal (Lead content) and drug chemical (Paracetamol) substances. The thermodynamics of redox potential and super-capacitor behavior of LCF NMs were investigated through Cyclic Voltametric (CV) and Electrochemical Impedance Spectral (EIS) methods under specific conditions at scan rate of 1 to 5 mV/s. The heterogeneous photo-catalytic process of prepared NMs on Fast orange Red (FOR) dye-decolouration was investigated and noted its excellent degradation (91.7%) at 90 min using 20 ppm of dye solution and 40 mg of synthesized samples under Sun-light irradiation. Further, the antibacterial activity of synthesized NMs is investigated against various strains of gram positive (Bacillus subtillis) and gram negative bacteria (Pseudomonas aeruginosa), which confirms that the LCF NMs have higher activity towards gram positive bacteria with an average inhibition zone of 19 mm. This synthesized LCF NMs is a multi-functional material with stable and eco-friendly materials. [ABSTRACT FROM AUTHOR]