Biosynthesizing of silver nanoparticles using microorganisms or various plant parts have proven more environmental friendly, cost-effective, energy saving and reproducible when compared to chemical and physical methods. This investigation demonstrated the plant-mediated synthesis of silver nanoparticles using the aqueous leaf extract of Thevetia peruviana. UV-Visible spectrophotometer was used to measure the surface plasmon resonance of the nanoparticles at 460 nm. Fourier Transform Infrared showed that the glycosidic -OH and carbonyl functional group present in extract were responsible for the reduction and stabilization of the silver nanoparticles. X ray diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy and Selected Area Electron Diffraction analyses were used to confirm the nature, morphology and shape of the nanoparticles. The silver nanoparticles are spherical in shape with average size of 18.1 nm. The synthesized silver nanoparticles showed activity against fungal pathogens and bacteria. The zone of inhibition observed in the antimicrobial study ranged between 10 and 20 mm.

In this report, synthesis, growth and formation kinetics of silver nanoparticles mediated by various plant extracts in their biodiversity have been monitored using UV-Vis spectrophotometer by sampling at time intervals during bioreduction process. Plasmon band resonance of the silver nanoparticles was observed as the reaction progresses indicating nucleation and particle formation. There were cases of red shifting indicating particle size increase. In the bioreduction process, onset of nanoparticle nucleation and growth were observed within 2, 5, 10 or 30 min and eventual formation of spherical or quazi-spherical amidst twinned morphology as determined by transmission electron microscope (TEM). The nanosilver growth kinetics mechanism has been probed using a time-resolved UV-Vis in conjunction with TEM following existing Lifshitz-Slyozov-Wagner theory. For some biological extractmediated synthesis, a single-stage mechanism that is diffusion controlled following Ostwald ripening (OR) is proposed. Whereas, for other bioreduction process, a double stage involving (1) initial OR followed by (2) surface adsorption-oriented attachment is proposed for temporal evolution of the nanosilver in green environment.

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A coordination polymer with the composition C 12 H 20 O 16 Zn 2 (ZnBTC) (BTC = benzene-1,3,5-tricarboxylate) was synthesized under hydrothermal conditions at 120 °C, and its crystal structure was determined using single-crystal X-ray crystallography. Firstprinciples electronic structure investigation of the compound was carried out using the density functional theory computational approach. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, the energy gap, and the global reactivity descriptors of ZnBTC were investigated in both the gas phase and the solvent phase using the implicit solvation model, while the donor−acceptor interactions were studied using natural bond orbital analyses. The results revealed that ZnBTC is more stable but less reactive in solvent medium. The larger stabilization energy E (2) indicates a greater interaction of ZnBTC in the solvent than in the gas phase. Orange peel activated carbon and banana peel activated carbon chemically treated with ZnCl 2 and/or KOH were used to modify the synthesis of ZnBTC to obtain nanocomposites. ZnBTC and the nanocomposites were characterized by powder Xray diffraction (PXRD), thermogravimetric analysis, and Fourier transform infrared. The specific surface area (S BET ) and the average pore diameter of the materials were determined by nitrogen sorption measurements using the Brunauer−Emmett−Teller (BET) method, while scanning electron microscopy and transmission electron microscopy were used to observe their morphology and particle size, respectively. The PXRD of all the activated carbon materials exhibited peaks at 2θ values of 12.7 and 13.9°corresponding to a d-spacing of 6.94 and 6.32 Å, respectively. The N 2 adsorption−desorption isotherm of the materials are of type II with nanocomposites showing enhanced S BET compared to the pristine ZnBTC. The results also revealed that activated carbons from the banana peel and the derived nanocomposites exhibited better porous structure parameters than those obtained from orange peel. The degradation efficiency of methyl orange in aqueous solutions using ZnBTC as a photocatalyst was found to be 52 %, while that of the nanocomposites were enhanced up to 79 %.