Sensitive and selective spectrophotometric determination of pantoprazole sodium in pharmaceuticals using permanganate

A simple visible spectrophotometric method is described for the determination of pantoprazole sodium sesquihydrate (PSS). The method is based on the formation of a brown colored product on treating PSS with permanganate in neutral medium, the absorbance being measured at 350 nm. The experimental conditions for the assay were optimized. The absorbance is found to increase linearly with the concentration of PSS and the calibration graph is linear in the range of 2.5-40.0 μg ml-1 with a linear regression coefficient of 0.998. The calculated molar absorptivity value is 1.27x104 l mol-1 cm-1 and the corresponding Sandel sensitivity is 0.0341 µg cm-2. The limits of detection (LOD) and quantification (LOQ) are calculated to be 0.49 and 1.47 µg ml-1, respectively. Intra-day and inter-day accuracy expressed as relative error were better than 2.0% and the corresponding precision (RSD) was less than 2.5 %. The developed and validated method was applied to the determination of the active ingredient in a tablet dosage form and the results obtained agreed well with those of the reference method. The accuracy and reliability of the method were ascertained by performing recovery experiments via standard-addition procedure

Recovery of Cu and Ni from a Secondary Resource by Hydrometallurgical Route

A high iron containing copper and nickel based secondary resource analysing 22.43% Cu, 7.94% Ni and 36.28% iron has been treated to recover valuable metals by leaching with sulphuric acid. It was found that recovery of copper and nickel increased with increase in temperature and sulphuric acid concentration and in a two-stage leaching with 20% (v/v) sulphuric acid at 368 K above 99.9% copper and 82.35% nickel were recovered. The leaching data best fitted into chemical controlled kinetic model showing chemical reaction at the surface of the solid matrix. Activation energy of 20 kJ/mol and 44 kJ/mol were acquired for dissolution of copper and nickel, respectively. Attempts were also made to separate iron from the leach liquor by using Versatic 10 and recovery of copper and nickel in the form of their sulphate by solvent extraction; the copper and nickel could then be recovered as salts, metal cathodes or metal powder

Takeovers, Governance and The Cross-Section of Returns

This paper considers the impact of the takeover channel on firm valuation. We use the idea that takeover activity responds to investor expectations of future rate of return and hence to state variable(s) related to the time variation in risk premia. Thus firms with higher exposure to takeovers, due to higher expectations of receiving a takeover premium, have a higher exposure to the state variable that dictates time variation in risk premia. Consequently, the difference in the returns between firms that differ in their takeover vulnerabilities can be used to used to proxy these state variables. To do so, we create a takeover-spread portfolio that buys firms with low cash-adjusted-leverage (cheaper targets) and shorts firms with high cash-adjusted-leverage and show that such a portfolio generates annualized abnormal returns of up to 11.20% between 1980 and 2003. Also, abnormal returns associated with governance-spread portfolios (Gompers, Ishii and Metrick, 2003 and Cremers and Nair, 2004) decrease significantly once the asset pricing model includes this ’cash-adjusted-leverage’ factor. Finally, we propose a new ‘takeover’ factor to proxy for the risk due to changes in these risk-premia related state variables, which is shown to be important in explaining cross-sectional differences in equity returns. The paper shows why investors require a higher rate of return on firms exposed to takeovers and yet value them higher than firms protected from takeovers

Bio-hydrometallurgical approach in processing of low grade Indian uranium ore in Column Reactor

In order to augment the supply of uranium for electricity generation, bioleaching is being considered for exploiting a low-grade uranium ore (with 0.024% U3O8 of Turamdih Mines, Jharkhand, India). This ore contains silicate and magnetite as the main minerals and uraninite and hematite as minor minerals. At NML, efforts have been made to use Acidithiobacillus ferrooxidans (Ac.Tf) initially on bench scale in shake flask and then in column to recover uranium. In shake flasks, ~98% uranium dissolution was achieved in 30days at 1.7pH, 35oC temperature and 20% (w/v) pulp density. In a laboratory scale column containing 2.5kg ore, uranium bio-recovery of 55.48% was obtained in 30 days at 1.7pH. To scale up the process, the bio-leaching experiments carried out on 80kg ore showed uranium recovery of 69.8% as against a recovery of 55.12% in control set at 1.7 pH in 50 days. Bio-recovery of uranium has been correlated with the change in redox potential (Eh) and ferric ion concentration

Biosorption of trivalent chromium from a model tanning solution by adapted aspergillus niger

Industrial effluents containing metallic species are responsible for environmental degradation which have been prioritised as major inorganic contaminants. Conventional methods are quite expensive resulting in need for cost-effective process for removing heavy metals from discharging effluents. The use of microbial biomass for removal of heavy metals from aqueous solutions (biosorption) is one such approach gaining increasing attention. Trivalent chromium ion present in tannery effluents has been the targeted ionic species for removal due to its exceeding limits in industrial discharges (<--0.3 ppm as per WHO). At NML, efforts were made for biosorption of trivalent chromium from tannery effluents with Cr (III) concentration in the range 1500-5000ppm. Aspergillus niger, obtained from a culture bank has been used in biosorption of trivalent chromium of tannery effluents. The fungal species grown in Czapek Dox Medium and adapted on Cr(III) ions ranging from 10-2000ppm at 2.5 pH and 35°C, was used for biosorption of chromium from a model tanning solution. A.niger was used in forms such as live, adapted and pre-treated (autoclaved, alkali-treated) for biosorption at pH 2.5 and 35°C. At Cr(IlI) conc. of 2000ppm in the aqueous solution, the adsorption efficiency followed the order: alkali treated (52%)>live(38%)>autoclaved dead mass(27%). The varying biosorption capacities may be attributed to exposed metal binding sites in alkali treated fungus causing high biosorption efficiency which also obeyed the sorption isotherm

Amenability of low- grade uranium towards column bioleaching by acidithiobacillus ferrooxidans

ABSTRACT : R & D studies were carried out at NML using Acidithiobacillus ferrooxidans (Ac.TJ in column for the bio-recovery of uranium from the low-grade uranium ore containing 0.024% U308 of Turamdih Mines, Singhbhum. A recovery of 55 .48% uranium was obtained in bio-leaching as against -- 44.0% in sterile control in 30 days at 1.7pH in a column containing 2 . 5kg ore of particle size mainly in the ra,., 5-1mm . In the large scale column , leaching with 80kg ore of particle size -0.5cm, uranium biorecovery was found to be 69.8% in comparison to a recovery of 55% in control set at 1.7 pH in 50 days. The uranium recoveries followed indirect leaching mechanism

Bioleaching - an alternate uranium ore processing technology for India

Meeting the feed supply of uranium fuel in the present and planned nuclear reactors calls for huge demand of uranium, which at the current rate of production, shows a mismatch. The processing methods at UCIL (DAE) needs to be modified/ changed or re-looked into because of its very suitability in near future for low-index raw materials which are either unmined or stacked around if mined. There is practically no way to process tailings with still some values. Efforts were made to utilize such resources (low-index ore of Turamdih mines, containing 0.03% U3O8) by NML in association with UCIL as a national endeavor. In this area, the R&D work showed the successful development of a bioleaching process from bench scale to lab scale columns and then finally to the India’s first ever large scale column, from the view point of harnessing such a processing technology as an alternative for the uranium industry and nuclear sector in the country. The efforts culminated into the successful operation of large scale trials at the 2ton level column uranium bioleaching that was carried out at the site of UCIL, Jaduguda yielding a maximum recovery of 69% in 60 days. This achievement is expected to pave the way for scaling up the activity to a 100T or even more heap bioleaching trials for realization of this technology, which needs to be carried out with the support of the nuclear sector in the country keeping in mind the national interest

Solvent extraction and separation of zinc and cobalt from ammoniacal solution

A process was developed to recover Zn and Co by solvent extraction from the raffinate generated during processing of sea nodules. From a model ammoniacal solution containing 0.2 g/L Zn or 0.2 g/L Co, extraction of Zn and Co by Versatic acid was studied. A maximum of 87% Zn was extracted with 1M Versatic acid in single stage, whereas extraction of Co was negligible due to its higher oxidation state. When Co(III) was reduced to Co(II) by the addition of cobalt powder, 1M Versatic acid extracted 76% Co in a single stage. From the McCabe Thiele diagram number of counter current extraction stages required for complete recovery of Zn and Co from ammoniacal solution was determined. Simulation of counter current extraction of Zn and Co was also carried out. Thus, this process can be used to recover Zn, leaving Co in the raffinate. Then Co can be recovered by solvent extraction with Versatic acid after reducing Co(III) to Co(II) state

Assessment of Diara land under Bhagalpur district using remote sensing and GIS tools

The Diara land is found in between the natural levees of the river and formed due to its meandering and course changing behavior. The topography of Diara land is mostly undulating and intersected with numerous dead and disconnected channels, Remote sensing and Geographical Information System (GIS) is a reliable technique to prepare a comprehensive inventory of land use pattern of an area. The present study was carried out to prepare a complete digital map of diara land of Bhagalpur district using spatial software (TNT Mips). On the basis of visual interpretation of the satellite image and physiographic pattern of the land escape, polygons were digitized for area delineation and mapping for diara land. Out of sixteen blocks of Bhagalpur district, only six blocks were identified as an old Diara land (203.26 km2) and thirteen blocks were identified as a new diara land (869.78 km2). Occupied areas viz. Narayanpur, Bihpur, Kharik, Naugachhiya, Ismailpur, Rangra Chowk and Gopalpur blocks were identified under complete diara land. No any one Diara land characteristics ware marked in Shahkund, Goradih and Sanhaula blocks