Biogenic synthesis of multi-applicative silver nanoparticles by using Ziziphus Jujuba leaf extract.

Herein, we are reporting for the first time one step biogenic synthesis of silver nanoparticles (AgNPs) at room temperature by using Ziziphus Jujuba leaf extract as a reducing and stabilizing agent. The process of nanoparticles preparation is green, rapid, environmentally benign and cost effective. The synthesized AgNPs were characterized by means of UV-Vis., XRD, FT-IR, TEM, DLS and Zeta potential. The absorption band centered at λmax 434 nm in UV-Vis. reflects surface plasmon resonance (SPR) of AgNPs. XRD analysis revealed, that biosynthesized AgNPs are crystalline in nature with the face centered cubic structure. FT-IR analysis indicates that nanoparticles were capped with the leaf extract. TEM images shows the synthesized nanoparticles are having different shapes with 20-30 nm size. The data obtained from DLS that support the hydrodynamic size of 28 nm. Zeta potential of -26.4 mV indicates that the nanoparticles were highly stable in colloidal state. The effect of pH, quantity of leaf extract and concentrations of AgNO3 were also studied to attend control over the particle size and stability. The synthesized AgNPs shows highly efficient catalytic activity towards the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) and Methylene Blue (MB) for environmental protection. Synthesized AgNPs also exhibited good antimicrobial activity against Escherichia coli.

Preparation of N doped TiO2 via microwave-assisted method and its photocatalytic activity for degradation of Malathion.

We report herein, nitrogen doped TiO2 nanostructure synthesized by simple microwave assisted method, where ammonia was used as hydrolyzing agent. The synthesized nanomaterials were characterized by means of X-ray diffraction (XRD) which demonstrated that N-doped TiO2 is in anatase phase with average crystallite size of 10nm. Doping of N into the lattice of TiO2 was supported by X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared spectroscopy (FT-IR), CHNS analysis, energy dispersive spectroscopy (EDS). The diffuse reflectance spectroscopy (DRS) showed shifting of absorption edge toward the visible region. Thermogravimetric-differential thermal analysis (TGA-DTA) points out N-doped TiO2 nanoparticles are thermally stable. In order to achieve maximum degradation efficiency, the effect of catalyst loading, pH and light sources (UV and sunlight) were studied. A maximum 97% degradation efficiency was achieved under optimized conditions. A 80% reduction in the chemical oxygen demand (COD) was observed after 150min that indicated mineralization of Malathion. The cytotoxicological studies indicate that photocatalytically degraded products were less toxic as compared to Malathion.

Highly active lanthanum doped ZnO nanorods for photodegradation of metasystox.

La-doped ZnO nanorods with different La contents were synthesized by microwave assisted method and characterized by various sophisticated techniques such as XRD, UV-Vis., EDS, XPS, SEM and TEM. The XRD patterns of the La-doped ZnO indicate hexagonal crystal structure with an average crystallite size of 30nm. It was found that the crystallite size of La-doped ZnO is much smaller as compared to pure ZnO and decreases with increasing La content. The photocatalytic activity of 0.5mol% La-doped ZnO in the degradation of metasystox was studied. It was observed that degradation efficiency of metasystox over La-doped ZnO increases up to 0.5mol% doping then decreases for higher doping levels. Among the catalyst studied, the 0.5mol% La-doped ZnO was the most active, showing high photocatalytic activity for the degradation of metasystox. The maximum reduction of concentration of metasystox was observed under static condition at pH 8. Reduction in the Chemical Oxygen Demand (COD) of metasystox was observed after 150min. The cytotoxicological studies of meristematic root tip cells of Allium cepa were studied. The results obtained indicate that photocatalytically degraded products of metasystox were less toxic as compared to metasystox.