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ESR Spectral Characterisation of Mn doped Zn (II) Trisethylenediamine Sulfidometalate Complexes
(Blue Eyes Intelligence Engineering and Sciences Publication, 2019) Vernekar, Beena K.
Aqueous reaction of Zn(II) and Mn(II) salts with ammonium tetrasulfidometalate (NH4)2[MS4] (M = Mo, W) in the presence of ammonia or ethane 1,2-diamine (en) or propane 1,2-diamine (1,2-pn) results in the formation of [M'(L)n][MS4] (M’ = Zn or Mn; L = NH3 or en or 1,2-pn). Using this strategy, Mn doped Zn complex of formula [Zn0.99Mn0.01(en)3][MS4], which exhibits characteristic hyperfine ESR spectra have been synthesized. The synthetic aspects, spectral and thermal characterization are described.
Comparison of degradation of methylene blue dye by zno, n doped zno and iron ore rejects
(Deuton-X Ltd, 2014) Borker, Vrinda; Mordekar, Rajashri Karmali; Rane, Koyar
Textile effluent containing unused dye when released in surroundings pollutes water bodies. It requires processing before disposal. Iron ore reject created during mining creates environmental pollution but contains minerals of technological importance. It has ~30-50 % iron in the form of γ-Fe2O3, α-Fe2O3 and Fe3O4 is wasted if thrown in fields, so can be used to degrade organic dyes. Mineralization of methylene blue, MB a model dye is carried out using photocatalyst either iron ore reject, synthesized ZnO or ZnO1-xNx and the results are compared. ZnO is synthesised from oxalate and nitrogen doped ZnO from hydrazinated oxalate precursors. FTIR study of zinc complexes indicates formation of precursors and XRD of decomposed complexes reveal formation of zinc oxide with wurtzite structure. The presence of nitrogen in ZnO1-xNx is confirmed by chemical estimation and XPS studies. SEM reveals the particle size of ZnO1-xNx ~69 nm and ZnO ~0.5-1μm. ZnO1-xNx absorbs in the visible region and ZnO in UV region. Band gap energy calculated using Diffuse reflectance Spectrum is 2.48 eV for the former, 3.19eV for the later and 2.38 eV for ore reject. Mineralizing property of ore reject, ZnO and ZnO1-xNx are compared by electrons spray ionisation mass spectrometry study (ESI-MS) of degradation products, COD measurement and CO2, NO3- and SO4-2 estimation. Reusability study, kinetic study of degradation of MB dye using photocatalysts and ESI-MS study of degraded products of MB reveal better efficacy of iron ore rejects amongst three. Thus efficiency of iron ore reject > ZnO1-xNx. > ZnO as photocatalyst.
Silver substituted cobalt zinc ferrites as magnetic antimicrobials
(Elsevier, 2023) Mordekar, Rajashri Karmali; Samant, Pranita; Mishra, Puja; Joseph, Jaison
Silver-substituted cobalt zinc ferrite series, CoxAg0.5-xZn0.5Fe2O4 (x = 0.4, 0.3, 0.2, 0.1), is synthesized using the citrate gel method, wherein ferrite formation is achieved at 600 °C. The low-temperature crystallization results in agglomerated and porous ferrites. In this sample preparation methodology, as the silver content in the series increases, metallic silver deposits at the grain boundaries, and vacancies are created at the octahedral sites. With a further increase in silver content, the magnitude of magnetic properties decreases. Antimicrobial activity increases and further decreases with an increase in silver content. The composition Co0.4Ag0.1Zn0.5Fe2O4 exhibits both magnetic and antimicrobial behaviour. These materials can potentially be beneficial in the manufacture of removable antimicrobial agents for water purification and drug delivery systems.
Insitu FTIR studies for the enhanced activity of Pt(HY) and Pt-Ru(HY) zeolite catalysts for electrooxidation of methanol in fuel cells
(Elsevier, 2020) Samant, Purnakala V.; Fernandes, Julio B.
Insitu FTIR (Fourier transform infrared spectroscopy) technique has been employed to study the oxidation of methanol on Platinum and Platinum - Ruthenium catalysts supported on HY zeolites [Pt-Ru (HY)/C]. The reaction has been studied by recording the spectra at different temperature ranges from room temperature till 170 °C. The catalytic activity has been studies in presence and absence of oxygen supply. The mechanism for oxidation of methanol has also been interpreted from the data obtained.
The decomposition of methanol on Platinum (HY)/C catalyst occurs via carbonate/formate pathway in presence of oxygen and carbonate/carboxylate in absence of oxygen. The optimum efficiency of the Pt (HY) catalyst occurs at 120 °C. But on the surface of Pt- Ru (HY)/C catalyst, methanol oxidation occurs at room temperatures, thus emphasizing higher catalytic efficiency. The enhanced activity of the Platinum–Ruthenium/HY has been explained on the basis of intermediates formed during the reaction.
Children's interest in viewing T.V. advertisements: Area, age and gender analysis
(SLAA Publications Pvt. Ltd., 2016) Divakar, Radhamani; AnjanaRaju, Guntur
This study was undertaken to analyse children's interest in viewing advertisements. An attempt has been made to find out what are the factors that influence children in watching advertisements, what are the reasons for watching advertisements and what are the types of advertisements that interest children the most. A sample of 1000 children of 6-12 years of age across Goa was selected. It was found that it is music and colour that attracts children in the age group of 6-12 from urban and rural areas to watch advertisements. The two prominent reasons for watching advertisement are its entertaining ability and ability to give product information. The type of advertisements that children love the most are chocolate ads and soft drink ads.