http://nopr.niscair.res.in/handle/123456789/2461 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/2479 Title: Degradation of organic effluents containing wastewater by photo-Fenton oxidation process <br/> <br/>Authors: Sheikh, Modh Azam; Kumar, Anil; Paliwal, Mukesh; Ameta, Rameshwar; Khandelwal, R C <br/> <br/>Abstract: Photooxidation of some organic pollutants (p-nitroaniline, p-aminophenols and acetanilide) has been carried out in the presence of photo-Fenton reagent. The effect of various parameters like pH, concentrations of organic compounds, ferric ions and hydrogen peroxide and light intensity, etc. on the reaction rate has been studied. The degradation is found to be pseudo first order. The optimum pHs for the degradation of p-aminophenol, p-nitroaniline and acetanilide are found to be 3.0, 3.5 and 2.5, respectively while the rate degradations of the three compounds are found to be comparable. The study shows that the photo-Fenton process are more effective and faster than Fenton's reagent in oxidation of organic compounds, and that the organic compounds are completely oxidized and degraded into CO₂ and H₂O. A tentative mechanism has been proposed. Excellent removal has been obtained using photo-Fenton process assisted with artificial irradiation. This study demonstrates that the use of photo-Fenton process on organic effluents wastewater treatment is very promising, especially when solar light is used. <br/> <br/>Page(s): 1681-1684 Wed, 29 Oct 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2478 Title: Synthesis of a new polymorph in [Cu(pyridine-2-carboxylate)₂] system <br/> <br/>Authors: Dutta, Daipayan; Jana, Atish Dipankar; Ray, Ambarish <br/> <br/>Abstract: Single crystal X-ray studies on a doubly carboxylate bridged {[Cu(pic)₂].2H₂O}ո (1) (pic = pyridine-2-carboxylate) polymeric chains extending along the crystallographic a axis reveal that adjacent polymeric chains are joined by the lattice water chains running parallel to the polymeric chain leading to a 2D sheet in the (101) plane. The successive sheets are interdigitated and glued to each other by a novel C=O…π interaction into a 3D supramolecular motif. The complex (1) can be regarded as a pseudo-polymorph of [Cu(pic)₂]ո which has been realized in two forms, violet (2) and blue-violet (3) from methanol. <br/> <br/>Page(s): 1656-1660 Wed, 29 Oct 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2477 Title: Silver selective electrode based on liquid membrane containing N₂S₂O₂ macrocycle as ionophore <br/> <br/>Authors: Mittal, Susheel K; Kumar, S K Ashok; Gupta, Nidhi Rani; Ocak, Mirac; Ocak, Ummuhan <br/> <br/>Abstract: Plasticized membrane using 5,6:17,18-dibenzo,11,12- (4-nitrobenzo)-2, 3-bis(hydroxyimine)-7,16-dithia-10, 13-dioxo-4, 19-diaazacyclooctadecane (N₂S₂O₂) based ionophore has been explored as Ag⁺ ion-selective sensor. Optimum performance is observed with membrane having composition of PVC, plasticizer and ionophore in the ratio of 33: 65: 2 (wt. %). Stability constants for different metal ions have been determined by conductometric titrations. The sensor works satisfactorily in the concentration range of 2.5×10⁻⁵ to 1.0×10⁻¹ M (detection limit 7.9×10⁻⁶ M) with a Nernstian slope of 58.5 mV/decade of activity. Wide pH range (5.0–9.0), fast response time (15 s), non-aqueous tolerance (up to 30%) and adequate shelf life (3 months) indicate the vital utility of the proposed sensor. The proposed electrode shows good selectivity for Ag⁺ ion with respect to alkali, alkaline earth, transition and rare earth metal ions and can be used for its determination in binary mixtures. Determination of chloride contents in samples of Vitamin B1 and tap water has also been made by using the proposed electrode. <br/> <br/>Page(s): 1676-1680 Wed, 29 Oct 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2476 Title: Kinetics and mechanism of Ru(III) catalyzed and uncatalyzed oxidation of atenolol by chloramine-T in perchloric acid medium <br/> <br/>Authors: Suresha, N <br/> <br/>Abstract: The kinetics and mechanism of chloramine-T (CAT)-oxidation of atenolol (ATN) in aqueous perchloric acid medium have been studied at 26 ± 0.1ºC in the presence and absence of Ru(III) catalyst. Under identical experimental conditions, the reaction shows a first-order dependence on [CAT]₀, a zero-order dependence on [ATN]₀ and an inverse fractional-order dependence on [H⁺] for both the Ru(III) catalyzed and uncatalyzed reactions. The order with respect to Ru(III) is unity. Variation of ionic strength and addition of p-toluenesulfonamide or chloride ion have no effect on the rate. Decrease in dielectric constant of the reaction medium decreases the rate constant in both cases. Activation parameters have been computed. The stoichiometry of the reaction is found to be 1:4 and the main oxidation products are identified as 4-acetamidobenzeneoxyacetic acid and isopropyl amine. Based on the kinetic data, the conjugate acid, CH₃C₆H₄SO₂NHCl, is assumed to be the reactive oxidizing species in both cases. The Ru(III) catalyzed reactions are 2-3 times faster than the uncatalyzed reactions. Mechanisms consistent with the observed rate laws have been proposed. <br/> <br/>Page(s): 1649-1655 Wed, 29 Oct 2008 22:58:59 GMT