Green Synthesis of Surfactant Capped CTAB@Ag Nanoparticles and Study of Its Catalytic Activity

In the present study, ginger extract, which is widely available as a medicinal herb, is used to develop a facile method for green synthesis of bare Ag and surfactant capped CTAB@Ag nanoparticles via Hydrothermal route. The as-prepared Ag nanoparticles were characterized by UV-Vis spectroscopy, photoluminescence (PL), X-ray Diffraction (XRD), Infrared spectroscopy (IR), and Scanning electron microscopy (SEM). The catalytic properties of as prepared bare and surfactant capped CTAB@Ag nanoparticles were also investigated in reductive degradation of Methyl Orange (MO) dye and 4-Nitrophenol (4-NP). Surfactant-capped CTAB@Ag nanoparticles exhibit superior catalytic properties in the degradation of MO and conversion of 4-nitro phenol to 4-amino phenol when compared to bare silver nanoparticles.

Recycling of Spent Hydrodehalogenation Catalysts – Problems Dealing with Separation of Aluminium

Our study is focused on utilization and recycling of copper and nickel applicable for reductive degradation of tetrabromobisphenolA (TBBPA), the high use brominated flame retardant for printed circuit boards. Deactivated and/or poisoned hydrodebrominationcatalysts are produced by reductive destruction of brominated phenol (TBBPA) dissolved in alkaline aqueous solution using RaneyAl-Ni and/or Devarda´s Al-Cu-Zn alloys. Spent metallic slurry is treated with aqueous sulfuric acid to dissolve residual aluminiumand/or zinc and decanted residual metal is subsequently treated under oxidation conditions and dissolved in excess of mineralacid by co-action of oxidant. The corresponding metal salt is separated from corresponding leachates containing excess of acid byevaporation and recycling of volatile components. Obtained copper or nickel salts were used as sources of Raney type hydrodebrominationcatalysts produced for in-situ by action of NaBH4.

Recyclable polymer microgel stabilized rhodium nanoparticles for reductive degradation of para-nitrophenol

The purpose of present work is to fabricate rhodium nanoparticles in Poly(N-isopropylmethacrylamide-acrylic acid) [p(NMAA)] microgel system. Synthesized polymer [p(NMAA)] microgels and rhodium nanoparticles loaded [Rh-p(NMAA)] microgels were analyzed by FTIR (Fourier Transform Infra-red) spectroscopy, XRD (X-ray Diffraction) analysis and UV/Vis (Ultraviolet–Visible) spectroscopy. Catalytic reductive conversion of P-nitrophenol (P-Nph) into P-aminophenol (P-Aph) via Rh-p(NMAA) was used to evaluate the catalytic activity of the hybrid microgel [Rh-p(NMAA)]. Kinetic study of catalytic reductive conversion of P-Nph was explored by considering various reaction parameters. It was found that the value of first order observed rate constant (k obs) was varied from 0.019 to 0.206 min−1 with change in concentration of sodium borohydride (SBH) from 3 to 14 mM at given temperature. However, further increment in concentration of SBH from 14 to 17 mM, reduced the value of k obs from 0.206 to 0.156 min−1. The similar dependence of k obs on concentration of P-Nph was observed at specific concentration of SBH and Rh-p(NMAA) at constant temperature. Kinetic study reveals that conversion of P-Nph to P-Aph takes place on the surface of rhodium nanoparticles (RhNPs) by adopting different reactions intermediates and obeys the Langmuir-Hinshelwood mechanism. Reduction efficiency of recycled Rh-p(NMAA) catalytic system was also measured and no significant reduction in the percentage catalytic activity was obtained up to four cycles for P-Nph conversion into P-Aph.