02423nas a2200181 4500008004100000022001400041245010200055210006900157260007100226300001400297490000700311520169600318100002102014700002402035700002902059700002602088856012702114 2007 eng d a0013-936X00aEffect of surface chemistry of Fe-Ni nanoparticles on mechanistic pathways of azo dye degradation0 aEffect of surface chemistry of FeNi nanoparticles on mechanistic a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV a7437-74430 v413 a

The degradation of Orange G a monoazo dye, in aqueous solutions was investigated using as-synthesized and stored Fe-Ni bimetallic nanoparticles. Batch experiments with a nanocatalyst loading of 3 g/L showed complete. dye degradation (150 mg/L) after 10 min of reactiontime. HPLC-MS analysis of the degradation products showed that assynthesized nanoparticles reductively cleaved the azo linkage to produce aniline as the major degradation product. However, 1-year-stored nanoparticles showed an oxidative degradation of Orange G through a hydroxyl-radical induced coupling of parent and/or product molecules. XPS analysis in corroboration with HPLC-MS data showed that the surface chemistry between Fe and Ni in assynthesized and stored nanoparticles play a crucial role. in directing the mode of degradation. Reductive dye degradation using as-synthesized nanoparticles proceeded through hydride transfer from nickel, whereas formation of a Fe (2+) -Ni(0) galvanic cell in stored nanoparticles generated hydroxyl radicals from water in a nonFenton type reaction. The latter were responsible for the generation of radical centers on the dye molecule, which led to a coupling-mediated oxidative degradation of Orange G. The generation of hydroxyl radicals is further substantiated with radical quenching experiments using ascorbic acid indicating that stored nanoparticles degrade Orange G through a predominantly oxidative mechanism. HPLC-MS and XPS analysis of dye degradation using as-synthesized nanoparticles exposed to air and water confirmed that the reductive or oxidative degradation capability of Fe-Ni nanoparticles is decided by the time and type of catalyst aging process.

1 aBokare, Alok, D.1 aChikate, Rajeev, C.1 aRode, Chandrashekhar, V.1 aPaknikar, Kishore, M. uhttps://library.ncl.res.in/content/effect-surface-chemistry-fe-ni-nanoparticles-mechanistic-pathways-azo-dye-degradation-002238nas a2200241 4500008004100000022001400041245010700055210006900162260007300231300001200304490000700316520138200323653001201705653001601717653000901733653001801742653001101760100002101771700002401792700002901816700002601845856012501871 2008 eng d a0926-337300aIron-nickel bimetallic nanoparticles for reductive degradation of azo dye orange G in aqueous solution0 aIronnickel bimetallic nanoparticles for reductive degradation of aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a270-2780 v793 a

The degradation of Orange G, a monoazo dye, in aqueous solutions was investigated using Fe-Ni bimetallic nanoparticles. Transmission electron microscopy (TEM) of as-synthesized nanoparticles showed the presence of spherical particles having a size of 20-40 nm. X-ray photoelectron spectroscopy (XPS) did not detect the presence of nickel on the nanoparticle surface, which suggested a uniform distribution of both metals inside the particle core. Batch experiments with a minimum nanocatalyst loading of 3 g/L showed complete dye degradation after 10 min of reaction time. The degradation efficiency was linearly dependent on the initial dye concentration, pH of the solution and total Fe-Ni catalyst concentration. The efficiency increased with increasing Fe-Ni concentration and decreasing pH of the solution, but decreased with an increase in the dye concentration. The degradation rate followed first order reaction kinetics with respect to the dye concentration. High performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of the degradation products revealed that the degradation mechanism proceeds through a reductive cleavage of the azo linkage resulting in the formation of aniline and surface-adsorbed naphthol amine derivatives. The latter are subsequently hydroxylated through an oxidative process. (C) 2007 Elsevier B.V. All rights reserved.

10aAzo Dye10aDegradation10airon10aNanoparticles10aNickel1 aBokare, Alok, D.1 aChikate, Rajeev, C.1 aRode, Chandrashekhar, V.1 aPaknikar, Kishore, M. uhttps://library.ncl.res.in/content/iron-nickel-bimetallic-nanoparticles-reductive-degradation-azo-dye-orange-g-aqueous-002009nas a2200265 4500008004100000022001400041245009700055210006900152260007300221300001200294490000800306520108900314653001501403653001601418653001601434653001301450653001201463653001801475100001901493700002101512700002401533700002901557700002601586856013101612 2010 eng d a0304-389400aReductive dechlorination of gamma-hexachlorocyclohexane using Fe-Pd bimetallic nanoparticles0 aReductive dechlorination of gammahexachlorocyclohexane using FeP aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a680-6870 v1753 a

Nanoscale Fe-Pd bimetallic particles were synthesized and used for degradation of lindane (gamma-hexachlorocyclohexane) in aqueous solution. Batch studies showed that 5 mg/Lof lindane was completely dechlorinated within 5 min at a catalyst loading of 0.5 g/L and the degradation process followed first-order kinetics. GC-MS analysis in corroboration with GC-ECD results showed the presence of cyclohexane as the final degradation product. The proposed mechanism for the reductive dechlorination of lindane involves Fe corrosion-induced hydrogen atom transfer from the Pd Surface. The enhanced degradation efficiency of Fe-Pd nanoparticles is attributed to: (1) high specific surface area of the nanoscale metal particles (60 m(2)/g), manyfold greater that of commercial grade micro- or milli-scale iron particles (similar to 1.6 m(2)/g); and, (2) increased catalytic reactivity due to the presence of I'd on the Surface. Recycling and column studies showed that these nanoparticles exhibit efficient and sustained catalytic activity. (C) 2009 Elsevier B.V. All rights reserved.

10aBimetallic10aCyclohexane10aDegradation10akinetics10aLindane10aNanoparticles1 aNagpal, Varima1 aBokare, Alok, D.1 aChikate, Rajeev, C.1 aRode, Chandrashekhar, V.1 aPaknikar, Kishore, M. uhttps://library.ncl.res.in/content/reductive-dechlorination-gamma-hexachlorocyclohexane-using-fe-pd-bimetallic-nanoparticles-000787nas a2200181 4500008004100000022001400041245013800055210006900193260007300262300001200335490000800347100001900355700002100374700002400395700002900419700002600448856013100474 2012 eng d a0304-389400aReply to comment on ``Reductive dechlorination of gamma-hexachlorocyclohexane using Fe-Pd bimetallic nanoparticles'', by C. Noubactep0 aReply to comment on Reductive dechlorination of gammahexachloroc aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT a392-3930 v2351 aNagpal, Varima1 aBokare, Alok, D.1 aChikate, Rajeev, C.1 aRode, Chandrashekhar, V.1 aPaknikar, Kishore, M. uhttps://library.ncl.res.in/content/reply-comment-reductive-dechlorination-gamma-hexachlorocyclohexane-using-fe-pd-bimetallic-0