T. Peter Amaladhas; M. Usha; S. Naveen
Abstract
Sunlight induced strategy for the rapid green synthesis of silver nanoparticles (AgNPs) is reported for the first time using aqueous leaf extract of Achyranthes aspera. On exposing a mixture of silver nitrate solution and aqueous leaf extract of A. aspera to sunlight, stable silver nanoparticles were ...
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Sunlight induced strategy for the rapid green synthesis of silver nanoparticles (AgNPs) is reported for the first time using aqueous leaf extract of Achyranthes aspera. On exposing a mixture of silver nitrate solution and aqueous leaf extract of A. aspera to sunlight, stable silver nanoparticles were obtained within few seconds. The water soluble biomolecules from the A. aspera served as both reducing and capping agents in the synthesis of silver nanoparticles. The nanoparticles were characterized using UV–Vis., Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and EDAX techniques. The pseudo first order rate constant kobs, for the formation of AgNPs was found to be 3.49 x 10 -2 min -1 . The particles were stable for 3 months. The nanoparticles were mono-dispersed, spherical in shape with the average size of 12.82 nm. FT-IR analysis revealed that the -OH groups, possibly, from saponin were responsible for the reduction of silver ions to silver nanoparticles (AgNPs). Thus prepared AgNPs have desirable cytotoxicity towards bacterial strains and fungus and the effect was compared with standard drugs, Amikacin and fluconazole respectively. This green and mild technique can be used for the large scale extracellular synthesis of silver nanoparticles and the AgNPs thus prepared may be used for biological applications.
T. Peter Amaladhas; S. Sheeba Thavamani
Abstract
A new route for the utilization of fly ash has been formulated. X-type zeolite has been synthesized from fly ash by alkali fusion followed by hydrothermal treatment. Ascorbic acid was used as a ligand for the synthesis of metal complexes of copper, nickel and vanadium encapsulated in the super cages ...
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A new route for the utilization of fly ash has been formulated. X-type zeolite has been synthesized from fly ash by alkali fusion followed by hydrothermal treatment. Ascorbic acid was used as a ligand for the synthesis of metal complexes of copper, nickel and vanadium encapsulated in the super cages of fly ash based zeolite (FAZ) by flexible ligand method and characterized by FTIR, XRD, Atomic Absorption Spectrometry (AAS), Ultra Violet–Visible spectroscopy and Thermo gravimetric analysis (TGA). The additional peaks corresponding to that of the complex have been observed which confirms the loading of the metal complexes in the zeolite cavities. The shifting of C=C-O stretching frequency found at 682 cm -1 in ascorbic acid to 601 cm -1 confirms the co-ordination of the ligand resulting in the formation of the metal complex. The thermo grams show deflation in three regions corresponding to the loss of the intra-zeolite water, metal complexes and the structural –OH group respectively. The catalytic activity of these complexes towards the liquid phase hydroxylation of phenol with hydrogen peroxide has been established. The extent of the reaction as a function of time has been investigated. Vanadium-ascorbate complex had the highest conversion of 78%. The product was identified as hydroquinol by GC-MS. This study reports a highly attractive catalytic method for the preparation of hydroquinol from phenol using aqueous hydrogen peroxide as the oxidising agent which is industrially significant.
T. Peter Amaladhas; S. Sheeba Thavamani
Abstract
Coal fly ash has been used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. The synthesized fly ash based zeolite (FAZ) has been characterized by various analytical techniques. Copper(II), Nickel(II) and Zinc(II) complexes of N,N 1 -ethylenebis (salicylamide) encapsulated ...
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Coal fly ash has been used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. The synthesized fly ash based zeolite (FAZ) has been characterized by various analytical techniques. Copper(II), Nickel(II) and Zinc(II) complexes of N,N 1 -ethylenebis (salicylamide) encapsulated in the supercages of FAZ have been prepared by flexible ligand method and characterized by Fourier Transform infra red spectroscopy (FTIR), X-ray diffraction (XRD) analysis, Scanning electron microscopy (SEM), Atomic absorption spectrometry (AAS), Ultra Violet – Visible spectroscopy and Thermo gravimetric analysis (TGA). These complexes have been found to catalyze the liquid phase hydroxylation of phenol with hydrogen peroxide to yield catechol. It appears to be the first report of catalysis of metal complex encapsulated in fly ash based zeolite.