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Ramamurthy G.,CSIR - Central Leather Research Institute | Ramalingam B.,CSIR - Central Leather Research Institute | Ramalingam B.,Anna University | Katheem M.F.,CSIR - Central Leather Research Institute | And 8 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2015

The solid and liquid waste management of tanneries has become a serious problem in the leather industry. In this study, we have attempted and succeeded in eliminating these pollutants by a novel method that has not been done anywhere so far. Keratin hydrolysate (KH) from poultry feathers has been utilized along with chrome shavings (CS) for total elimination of the polluting solid and liquid wastes in a tannery. In this process, 100% fixation of the Cr from the chrome exhaust liquor and the dye from the dye exhaust liquor is achieved by the reactions of CS with KH. The infrared spectra of the different stages of CS confirm the fixation of Cr in the chrome shavings-keratin hydrolysate (CSKH) complex. In this work, apart from elimination of tannery pollutants, a leather-like flexible sheet is obtained that can be used in the footwear and leather goods industry. In the scanning electrom microscopy evaluation, the surface morphology of the product exhibits smoothness because of the incorporation of poly(vinyl alcohol) and ethylene glycol. The above findings will open new avenues for further research in solid and liquid waste management of tannery effluents. (Figure Presented). © 2015 American Chemical Society. Source


Singhbabu Y.N.,Academic of Scientific and Innovative Research AcSIR | Singhbabu Y.N.,Indian National Metallurgical Laboratory | Kumari P.,Indian National Metallurgical Laboratory | Parida S.,Indian National Metallurgical Laboratory | And 2 more authors.
Carbon | Year: 2014

An efficient method for the conversion of pyrazoline to pyrazole in hydrazine treated N-substituted reduced graphene oxide (N-rGO) films at room temperature has been reported. This method comprises the Ar+ ion bombardment of the N-rGO films that are prepared by drop casting method. The X-ray photoelectron spectroscopy (XPS) data in association with the X-ray diffraction, Ultra-violet spectroscopy and Raman spectroscopy data reveal that the addition of hydrazine removes the epoxy and hydroxyl groups of graphite oxide largely, and the reaction of hydrazine with carbonyl groups at 1,3-position of GO yields the pyrazoline moiety at the edge of the exfoliated carbon network. Further, the XPS data of the bombarded N-rGO films at the threshold applied potential of ∼3 keV for 10 min show that the position of the N1s XPS peak shifts from 400.05 to 398.6 eV due to the bombardment, indicating a conversion occurs from non-aromatic pyrazoline to aromatic pyrazole moiety. The electrical results reveal that the conductivity of the N-rGO/pyrazole film (47,600 S/m) is higher than the N-rGO/pyrazoline film (25,000 S/m) by virtue of the enhancement in the length of the conjugation π bond. The conversion of pyrazoline to pyrazole is discussed based on the activation energy. © 2014 Elsevier Ltd. All rights reserved. Source


Singhbabu Y.N.,Academic of Scientific and Innovative Research AcSIR | Singhbabu Y.N.,Indian National Metallurgical Laboratory | Choudhary S.K.,Tata Steel | Shukla N.,UGC DAE CSR Kalpakkam Node | And 3 more authors.
Nanoscale | Year: 2015

We report a large positive magneto-resistance (MR) in bubble decorated graphene oxide films that are derived from shellac biopolymer as a carbon source. These films were produced on a quartz substrate by heating the biopolymer coated substrate at 900 °C in an argon atmosphere. The characterization data of the films using Raman, X-ray photoelectron spectroscopy, field emission scanning electron microscopy and transmission electron microscopy reveal that shellac can be used as a new carbon source to produce transparent bubble decorated graphene oxide films. The magneto-resistance results show a 130% change in the resistance of the films at 3 K under a perpendicular magnetic field of 15 T, and the value decreases exponentially up to 50 K. The observed MR properties of the bubble decorated graphene oxide films are explained using a weak anti-localization and quantum interference model in the low magnetic field region, while the Lorentz force accounts for the MR properties well in the high magnetic field region. This journal is © The Royal Society of Chemistry. Source


Singhbabu Y.N.,Academic of Scientific and Innovative Research AcSIR | Singhbabu Y.N.,Indian National Metallurgical Laboratory | Sivakumar B.,Academic of Scientific and Innovative Research AcSIR | Sivakumar B.,Indian National Metallurgical Laboratory | And 5 more authors.
Nanoscale | Year: 2015

We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (∼3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600°C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350°C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is discussed based on the impermeability of graphene oxide to the corrosive ions. © The Royal Society of Chemistry 2015. Source

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