VOLUME 27, NO2, APR 2005

Upgradation of Chalcopyrite Ore by Flotation

The effect of important parameters e.g. conditioning time, collector, concentration, pulp, density, temperature, pH, particle, size, quality collector ,chain, length and cyandiation were studied thoroughly on the adsorption of xanthane ions and the subsequent floatation of chalcopyrite. Stepwise enhancement in upgradation and recovery was achieved by employing these parameters. After fully optimizing the parameters, the copper contentmwas upgrated from 0.8% to 18.75% achieving a recover of 85.25%.read more

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S MUSTAFA ,A HAMID ,A NAEEM ,S MURTAZA ,

Heating Value Characteristics of Sewage Sludge: A comparative Study of Different Sludge Types

Heating value characteristics of three different types of sludge i.e. domestic sewage sludge, industrials+domestic sewage sludge (thickened) showed the highest heating value (5040 kcal/kg) than order sludge types. This may be due to increased amount of organic matter presents in thickened sludge than de-watered sludge. A gradual increase in organic matter of the sludge was observed with the increase of the moisture contents. Heating value of the sludge having 60% moisture contents was found in the range between 924-1656 kcal/kg and this amount was higher than the minimum heating value (800 kcal/kg) required sustaining auto thermal combustion in sludge incineration process. Energy consumption requirement for pre-dying sludge operations revealed that the industrials sludge (de-watered) required the minimum cost (13 $/ton of sludge) to make it a sludge of fuel grade (60% W), while mixed slughe cost the highest amount for its pre-drying operations.read more

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T QURESHI ,HAE OK KANG ,YOUNG JU KIM ,

Study of Ion-Solvent Interactions of Lithium Bromide in, DMSO, H2O and DMSO-H2O Mixtures at 25oC

The relative viscosities were measured for LiBr and refrence salt Bu4BBPh4, KCl in wide range composition of mixture of DMSO and water at 25oC to obtain jones-Dole b-coefficients. The b-coefficients of these electrolyes in DMSO were positive which behave as structure makers while in H2O and DMSO-H2O) mixture, the b-coefficients values are less positive showing weak structure-making effects. The values of ionic b-coefficients are suggesting that the Li+ ions is structure-maker while Br- is structure-breaking in H2O and Mix III i.e. 20% DMSO + 80% water.read more

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T ZAMIR ,A KHAN ,

Kinetics and Mechanism of Reduction of A Binuclear Complex FeIII.L,CoIII by Hydroquinone

Fully oxidized binuclear complex FeIII.L,CoIII complex was synthesized by reaction of salicylato pentaammine cobalt (III) with ferric nitrate. Reduction kinetics of FeIII.L,CoIII by hydroquinone i.e. (H2Q) was followed spectrophotometrically FeIII.was redueced rapidly but Com was not.Reduction kinetics follows the rate law Kinetics measurements have been carried out at four different temperatures and pH. Temperature has no effect on the value of k2/k3. Redox potential (Eo) of the complex at different pH were determined by cyclic voltamery. The mechanism of this reaction is discussed in the context of Marcus cross relation for outer sphere process.read more

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S A KAZI ,D A WAQAR ,

Kinetics of the Thermal Gas Phase Decomposition of Methylcyclopropanecarboxylate Using static Method

Thermal decomposition of methylcyclopropane-carboxylate (MCPC) was studied over the temperature range 682-739k and presuure between 5-50 tburr using static system. Isomerization reaction to give methyl-3-butenoate, methyl-2-butenoate (cis+trans) and methyl-2-propenoate accounted for 95% of the methycyclopropane-carboxylate decomposition   These isomerizations are homogeneous first order, non-radical processes Arrhenius parameters are given in the rate equation:   Ktotal/s-1 = 10.13.7±1.2 exp(-236.9±16.8kj mol-1/RT) k1/s-1+13.3±1.6 exp(-243.6±22.5 kjmole-1/RT ); k2/s-1 1013.7±1.4 exp(-233.8±18.6 kjmole-1/RT); k3/s-1+10 13.9±0.8 exp(-251.3±10.7 kj mole -1/RT)       Error limits quoted are statistically 95% certainly limits. The observed Arrhenius parameters are consisitent with the biradical mechanism. Results from the present study are compared with those for cyclopropane isomerization to propane and it is found that the presence of CH3OC=O group on cyclopropane increases the rate constant for structural isomerization by lowering the activation energy for the reaction by 35 kJ mole-read more

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M ALI ,I A AWAN ,J NISAR ,T MAHMOOD ,

Characterization of Phenolphthalein Poly (aryl ether Sulfone)

Four narrow molecular weight distributed fraction of phenolphthalein poly (aryl ether sulfone) (PES) were studied in CHCl3 by static laser light scattering LLS, and viscometry at 25 oC. From static the weight-average molecular weight (Mw), z-average radii of gyration;<Rs2> ½ second virial coefficients A2 of the PES samples were determined. From viscometry, the reduced and intrinsic viscosities of all the fractions were measured and the corresponding intrinsic viscosities were determined. The intrinsic viscosities scaled with their molecular weight obtained through static LLS, yielding a Mark-Houwink equation of [h} = 4.42 x 10-2 M0.686. The exponent value indicates that PES in CHCL3 has a coil chain conformation. The value of αh obtained from viscosity is comparable with αD obtained previously from dynamic LLS.read more

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M K BALOCH ,K MAHMOOD ,M SIDDIQ ,

Sediment Analysis of Sewage Contaminated Canal

Sediment of sewage contaminated Fuleli canal was sampled, before and after addition of sewage for over 25 k.m. and analysed for loss on iginition, pH, conductance, organic carbon, water soluble chloride, sulphate, carbonate, phosphate, Na, K, Ca and Mg. the sediments were also examined for total (Fe, Cu, Ni, Mn, Zn, Pb, Co and Cd) and bioavailable (Fe, Mn, Cu and Zn) metal contents.The sediments showed alkaline character and contained wide range of variation in soluble salts. The major cations and total metal contents indicated following decreasing pattern Ca> Mg> Na> K. Fe>> Mn> Zn> Ni> Cu> Pb> CO> Cd.The bioavilable metal contents crossed crossed the safe limits for the use of sediments of contaminated portion of the canal for agricultural purpose.read more

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V K DEWEANI ,M Y KHUHAWAR ,I A ANSARI ,

Preconcentration and Atomic Adsorption Spectrometric Determination of Cadmium, Cobalt, Copper, Iron, Lead, Maganese, Nickel and Zinc in water Samples Using 6-Methyl-2-pyridinecarboxaldehyde-4-phenyl-3-thiosemicarbazone

The reagents 6-methyl-2-pyridinecarboxaldehyde-4-phenyl-3-thiosemicarbazone (MPAPT) has been examined for the pre-concentration of metal ions and determinations using air acetylene flame atomic adsorption spectrometer. The method is based on the complexation and extraction of cadmium(II), cobalt(II), zinc(II) in chloroform. The metals ions back extracted in nitric acid (1:1) or after evaporation of solvent the residue is digested in nitric acid. After necessary adjustment of volume the metal ions were determined in aqueous solution. Pre-concentration is obtained 10-25 times. Metal ions recovery was 95.4-100.8% with coefficient of variation 0.2-7.5%. The method was used for the determination of metals in canal and sewerage waters, within 2-6433 mg/I, with CN 0.2-5.2%.read more

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V K DEWANI ,M Y KHUHAWAR ,P DAS ,

Determination of Olanzapine by UV Spectrophotometry and Non-aquous Titration

Two new methods for the determination of olanzapine, based, on UV spectro photometry and non-aqueous titration, have been developed. The UV absorbance of the methanolic solution of olanzapine was measured at 2.26nm. the method obey Beer’s Law from 0.1 mg to 50 ug/ml and the inter-day precision of UV procedure is 97%. The non-aqueous titration was carried out by titrating olanzapine withy 0.1 N perchloric acid, using naphthobenzene as an insicator, and the inter-day precision is 0.35%. the developed procedures provide a basis for a new spectrophotometric  and a non-aqueous titrimetric determination of olanzapine. The quantative assessment of tolerable amount of commonly used excepients and other similar acting drugs were also studied for both the procedures. The proposed methods were applied to the analysis of pure and pharmaceutical dosage form of olanzapine. The percentage recovery in both the procedures lies between 99.0 and 100.67%.read more

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T AMAN ,S FIRDOUS ,ALIM UN NISA ,

Studies About Determination of Ascorbic Acid by Differential Pulse Voltammetry

Asobaric acid (Vitamin C) is one of the most important ingredients of food, fruits, vegetables and many pharmaceutical tablets and preparation. A differential pulse voltammetric method has been develop for the analysis of ascorbic acid in acetate buffer. Effects of pH was studied on the determination of ascorbic acid. At lower pH one electron and at higher pH two electrons transfer reaction takes place. At higher pH sensitivity of the method increase significantly. Air (oxygen) and higher pH accelerate the decomposition of asobaric acid. Hanging mercury drop electrode (HMDE) was used for the determination of ascorbic acid as working electrode. Initial potential was 0-3V  with scan rate of 10mV/s and the peak appeared at about +0.005V. Ascorbic acid can be measured in the methods different pharmaceutical tablets were analysed for levels of Vitamin-C. after dissolution of tablets in water aliquots were taken into acetate buffer and determined applying the standard addition method. Different types of fruit juices were also analysed for Vitamin-C. Levels of ascorbic acid in juices were in the ranges of 24 to 225 mg/100 ml.read more

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VIQAR UN NISA ,S A QURESHI ,R AHMED ,