http://nopr.niscair.res.in/handle/123456789/5905 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/5934 Title: Influence of preparation method on the performance of Pd/ ZrO₂-Al₂O₃ catalysts for HDS <br/> <br/>Authors: Chen, Sufen; Luo, Laitao; Cheng, Xinsun <br/> <br/>Abstract: ZrO₂-Al₂O₃(I) and ZrO₂-Al₂O₃(S) mixed supports were prepared using impregnation and sol-gel methods, separately. Influences of preparation methods on the properties of Pd based catalysts for hydrodesulphurization (HDS) of thiophene were studied. The prepared samples were characterized by means of XRD, H₂-TPD, H₂-TPR, XPS, NH₃-TPD, H₂ chemisorption and BET surface area. Pd/ZrO₂-Al₂O₃(S) catalyst supported on ZrO₂-Al₂O₃(S) exhibited much higher HDS activity than that of the Pd/ZrO₂-Al₂O₃(I) catalyst supported on ZrO₂-Al₂O₃(I). As compared with Pd/ZrO₂-Al₂O₃(I) catalyst, Pd/ZrO₂-Al₂O₃(S) catalyst has higher dispersion, more acid sites and stronger interaction between palladium and mixed support, which presented an increasing driving-force toward the catalyzed conversion of thiophene. <br/> <br/>Page(s): 272-277 Tue, 28 Apr 2009 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/5933 Title: Selective complexometric determination of palladium with sodium metabisulphite as releasing agent <br/> <br/>Authors: Shetty, Prakash; Shetty, A Nityananda <br/> <br/>Abstract: Sodium metabisulphite has been proposed as a selective releasing agent for the rapid and selective complexometric determination of palladium. Pd(II) present in a given sample solution is first complexed with excess of EDTA and the surplus EDTA is back titrated with standard zinc sulphate solution at <i>p</i>H 5-5.5 (acetic acid-sodium acetate buffer) using xylenol orange as indicator. Sodium metabisulphite solution is then added to displace EDTA quantitatively from the Pd-EDTA complex. The released EDTA is back titrated with standard zinc sulphate solution as before. The method works well in the concentration range 2-20 mg of Pd with a relative error ≤ 0.40% and relative standard deviation ≤ 0.65%. The method has been applied to the determination of palladium in catalysts, alloys and complexes. <br/> <br/>Page(s): 259-264 Tue, 28 Apr 2009 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/5932 Title: Kinetics and thermodynamics of copper ions removal from aqueous solution by use of activated charcoal <br/> <br/>Authors: Dave, Pragnesh N; Subrahmanyam, N; Sharma, Surendra <br/> <br/>Abstract: A study on the adsorption of copper from aqueous solutions on activated charcoal has been carried out with an aim to obtain information on treating effluents from metal finishing industries. The effects of various experimental parameters like contact time, dosage of activated charcoal, initial concentration of metal ions, <i>p</i>H etc. have been investigated. The percentage removal of metal ions increased with the decrease in initial concentration and increase in contact time, dosage of adsorbent and initial <i>p</i>H. Adsorption data were modeled with the Freundlich and Langmuir adsorption isotherms, various first order kinetic equations <i>viz</i>. Lagergren, Natarajan-Khalaf and Bhattacharya and Venkobachar equations and intra particle diffusion model. These isotherms, first order equations and models were found to be applicable. The kinetics of adsorption is found to be first order with intra particle diffusion as the rate determining step. Removal of metal ions using activated charcoal is found to be favourable and hence it could be used as an adsorbent for the treatment of effluents from metal finishing industries, especially for the removal of metal ions. <br/> <br/>Page(s): 234-239 Tue, 28 Apr 2009 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/5931 Title: Kinetics and mechanism of esterification of isoamyl alcohol with acetic acid by immobilized lipase <br/> <br/>Authors: Gogoi, Sumbita; Dutta, N N <br/> <br/>Abstract: In this study, the effects of the rate enhancement of isoamyl acetate formation by immobilized <i>Mucor miehei</i> lipase catalysed esterification of isoamyl alcohol with acetic acid were investigated. The esterification reaction was studied in ten different solvents and <i>n</i>-heptane was found to be most suitable. The rate of the reaction was affected by the addition of molecular sieves (3Å) and temperature. The effects of different reaction parameters such as lipase and substrate concentrations were studied. The activity of immobilized lipase was found to be maximum at lipase concentration of 12 mg/mL and at a reaction temperature of 55ºC; retained about one third of its initial activity up to seven reaction cycles after repeated use. The kinetics of the reaction can be described by Ping-Pong Bi-Bi mechanism with acid inhibition. The parameter values were estimated by non-linear regression analysis. <br/> <br/>Page(s): 209-215 Tue, 28 Apr 2009 22:58:59 GMT