http://nopr.niscair.res.in/handle/123456789/8567 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/8683 Title: Removal and recovery of nitrate from water by ZnCl₂ activated carbon from coconut coir pith, an agricultural solid waste <br/> <br/>Authors: Namasivayam, C; Sangeetha, D <br/> <br/>Abstract: Nitrate removal from aqueous solution was investigated using ZnCl₂activated carbon developed from coir pith. Influence of contact time, adsorbent dose, nitrate concentration, pH and temperature were investigated. Two theoretical adsorption isotherms namely Langmuir and Freundlich were used to describe the experimental results. The Langmuir adsorption capacity (<i style="">Q</i>_o) was found to be 10.3 mg nitrate per g of the adsorbent. Adsorption followed second order kinetics. Adsorption was maximum in the pH range 3-10. pH effect and desorption studies showed that ion exchange mechanism might be involved in the adsorption process. Effects of foreign ions such as chloride, sulphate, phosphate and perchlorate on the removal of nitrate have also been investigated. Removal of nitrate from ground water was also tested. Results show that ZnCl₂ activated coir pith carbon is effective for the removal of nitrate from water. <br/> <br/>Page(s): 513-521 Mon, 29 Aug 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8682 Title: Platinum—From exotic to commodity <br/> <br/>Authors: Wisniak, Jaime <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Platinum was brought to Europe in the middle of the sixteenth century and was soon recognized a true metal, which could not be fused. It remained an expensive curiosity for almost 200 years, until scientists learned its properties, how to melt it in large quantity, and discovered that four new elements, rhodium, iridium, osmium, and palladium, accompanied it (the platinum group metals). The early uses of platinum were in jewelry, laboratory ware, and coin manufacture. By the end of the nineteenth century a platinum-rhodium alloy was adopted for constructing the standard meter and kilogram. Production of platinum grew very slowly; it was only about one ton per year by 1911. The breakthrough came with the discovery of the extraordinary the catalytic properties of the platinum metal group. Today these metals stand at the heart of the petrochemical industry and are the basis of all the means for controlling the emission of obnoxious gases of motor vehicles. Annual production has now reached near 190 tons. </smarttagtype> <br/> <br/>Page(s): 601-614 Mon, 29 Aug 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8681 Title: Study of water vapour adsorption on nickel-chromia H-D exchange catalyst <br/> <br/>Authors: Gill, J S; Ramakrishnan, P; Singh, H <br/> <br/>Abstract: Adsorption of water vapour on a series of nickel-chromia samples has been studied. Nickel-chromia, with 15% chromium is an active catalyst for H-D (hydrogen-deuterium) exchange in hydrogen-water system, where water is in vapour phase. Water vapour adsorption/desorption indicate that it is adsorbed on the catalyst both physically and chemically. The 15% chromium catalyst sample has been treated with phenylethyl triethoxy silane to make it hydrophobic and active in liquid water-hydrogen system of H-D exchange. Water vapour adsorption isotherm on the treated sample shows the hydrophobization of the catalyst. <br/> <br/>Page(s): 559-562 Mon, 29 Aug 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8680 Title: Four rapid and sensitive methods for the assay of amoxycillin in pharmaceuticals using bromate-bromide mixture and two dyes <br/> <br/>Authors: Ramakrishna, V; Basavaiah, K <br/> <br/>Abstract: Four new methods using titrimetry and spectrophotometry are described for the rapid determination of amoxycillin in bulk drug and dosage forms. In direct titrimetry (Method A), the drug is titrated with bromate–bromide mixture in acid medium using methyl orange indicator. Back titrimetry (Method B) entails adding a known excess amount of bromate-bromide mixture to the drug solution in acid medium, followed by determination of residual bromine iodometrically. Both spectrophotometric methods are based on the oxidation–bromination of amoxyciillin by <i style="">in situ</i> generated bromine followed by estimation of unreacted bromine with methyl orange (Method C) or indigo carmine (Method D) and measuring the change in absorbance at 520 or 610 nm. In all the methods, qunatitation is based on the amount of bromate that has reacted with amoxycillin. The experimental conditions have been optimized. Calculations are based on 1:1 and 1:2 (amoxycillin: bromate) stoichiometry for method A and Method B, respectively. Method A is applicable over 2-16 mg range, and 1-9 mg of amoxycillin could be determined by method B. In spectrophotometric methods, the absorbance is found to increase linearly with increasing concentration of amoxycillin which is corroborated by the calculated correlation coefficient (<i style="">r</i>) of 0.9964 (Method C) and 0.9959 (Method D). The calibration graphs are found to be linear over 0.1–1.2 and 0.5 – 4.0 <img src='/image/spc_char/micro.gif' border=0> g mL^-1for method C and method D, respectively. Method C with a molar absorptivity of 1.60 <img src='/image/spc_char/cross.gif' border=0> 10⁵ L mol^-1cm^-1is found to be more sensitive than method D (ε = 5.83 <img src='/image/spc_char/cross.gif' border=0> 10⁴ L mol^-1cm^-1). The limits of detection and quantification for both spectrophotometric methods are reported. Statistical evaluation of the methods was examined by determining intra-day and inter-day precisions. The methods were applied to the determination of amoxycillin pharmaceutical formulations. No interference was observed from excipients and the validity of the methods was tested against a reference method. <br/> <br/>Page(s): 543-549 Mon, 29 Aug 2005 22:58:59 GMT