VOLUME 33, NO3, JUN 2011

Biofouling Management in the Cooling Circuit of a Power Industry Using Electrochemical Process

Biofouling is one of the major issues in the power industry using seawater for cooling and other purposes. Presence of biological organisms such as bacteria and algae that could foul pipes and expensive equipments need to be managed from economical and safety point of view. Generally, the biofouling problem is aggravated in hot climate regions. Various means of disinfection processes are available for this purpose, such as chlorination, UV or ozone.  In the present study electrochemical technology for the production of sodium hypochlorite was evaluated for onsite disinfection of seawater for applications in a nuclear power industry.  A continues flow laboratory scale experimental setup was fabricated and influence of various operating parameters such as electrode material, applied current density, power consumption, surface area of electrode and interelectrode spacing were evaluated.  It was found that efficiency of the electrochemical disinfection process was strongly dependent on these studied operating parameters. It was concluded that the production of sodium hypochlorite on site using an electrochemical process is a feasible and promising option for the power industry using seawater as cooling and/or process water.  An optimum design of the electrochemical cell was also suggested.read more

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MUHAMMAD SALEEM ,

Effect of Agitation Speed on Adsorption of Imidacloprid on Activated Carbon

The adsorptive characteristics of imidacloprid on powdered activated carbon were described. The adsorption experiments were carried out as function of time, initial concentration and agitation speed. The equilibrium data fits well to Langmuir adsorption isotherm, while the kinetic data fits well to Pseudo second order kinetic model. The kinetic experiments were carried out at 200, 250, 300 and 350 rpm and it was found that the equilibrium time increases with increase in initial concentration and decreases with increase in agitation speed. This is due to the increased turbulence and as a consequence, the decrease boundary layer thickness around the adsorbent particles as a result of increasing the degree of mixing. At 300rpm the adsorption capacity was maximum and beyond this there was no significant increase in adsorption capacity. Weber intraparticle diffusion model was used to describe the adsorption mechanism. It was found that both the boundary layer and intraparticle diffusion for both adsorbents played important role in the adsorption mechanisms of the adsorbate. The effects of temperature and pH on adsorption were also studied. It was found that the adsorption capacity of the adsorbent decreases with increase in temperature. There was no significant change in adsorption from pH 2 to 8, however at high pH a decrease in adsorption of imidacloprid on activated carbon was observed.read more

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MUHAMMAD ZAHOOR ,

Nutritional Values in Aspects of Essential and Non Essential Elements in Variety of Milk Samples by AAS and FES

Milk makes a significant contribution to the human diet through provision of macro nutrient, vitamins and minerals. The exact composition of milk varies by species to naturally or contamination. It is recognized that imbalance quantity of minerals and trace element being a serious health hazards especially for infants. Therefore, some essentials elements like  K, Fe, Co and Pb (as a non essential element) have been determined in locally available milk powder of infant formulas, milk powder of growing children , processed milk or tetra pack milk of different brands and fresh milk samples (cow and buffalo) by sophisticated analytical techniques flame emissions spectroscopy (FES) and atomic absorption spectroscopy (AAS). The range of mean concentration of elements (K, Fe and Co) in milk samples was found to be 650.00-1500.00mg/l, 2.76-8.93mg/l and 0.05mg/l respectively. The levels of these elements in milk powder of infant formulas (1&2) were compared with the standards of FAO/WHO, recommended values of the Committee on Nutrition of the American Academy of Pediatrics, human milk and cow’s milk.read more

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MAJID MUMTAZ ,TALAT MEHMOOD ,QAMARUL- HAQUE ,RUBINA PERWEEN ,

Adsorption of Gold (III) from Aqueous Solutions on Bagasse Ash

To assess the potential of cheap biomass materials for the recovery of gold from industrial, and electroplating waste water effluents, adsorption of gold (III) from dilute solutions of hydrochloric acid on bagasse ash has been studied under various experimental conditions by using batch technique. Percentage extraction of gold (III) on bagasse ash was determined from its distribution coefficients as a function of contact time, pH, adsorbent, adsorbate concentrations, and temperature. The uptake of gold (III) by bagasse ash is time, pH, metal concentration, amount of adsorbate, and temperature dependent. Adsorption data have been interpreted in terms of Langmuir, and the Freundlich equations. Thermodynamic parameters for the adsorption of gold (III) on bagasse ash have been determined at three different temperatures. The positive value of heat of adsorption; ΔHo = 44.52 kJ/mol shows that the adsorption of gold (III) on bagasse ash is endothermic where as the negative value of ΔGo = -0.5303 kJ/mol at 318 K shows the spontaneity of the process. ΔGo becomes more negative with increase in temperature which shows that the adsorption is more favorable at higher temperatures. Under the optimal adsorption conditions the adsorption capacity of gold is 0.70 mg /g of the adsorbent out of which 0.65 mg of gold gets desorbed with 0.1 % thiourea solution.read more

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GHULAM HUSSAIN ,M. ALI KHAN ,

Spectrophotometric Determination of pKa’s of 1-Hydroxybenzotriazole and Oxime Derivatives in 95% Acetonitrile-Water

1-hydroxybenzotriazole derivatives are used with carbodiimide as additives to generate active esters during peptide bond formation. They are also used as additives during the peptide bond formation. Dissociation constants of the 1-hdroxybenzotriazole (HOBt) and its derivatives, 1-hydroxy-6-chlorobenzotriazole, 1-hydroxy-6-trifluoromethylbenzotriazole, 1-hydroxy-6-nitrobenzo-triazole were determined spectrophotometrically in 95% acetonitrile-water. In addition, 7-aza-1-hydroxybenzotriazole (7-HOAt) and 4-aza-1-hydroxybenzotriazole (4-HOAt) were also studied. Recently, oxyma was reported as a good replacement for the benzotriazole derivatives. As alcoholic components of active esters, the oximes seem to be good leaving groups. Therefore it was expected, that the strongly acidic and nucleophilic oximes, which possess electron-withdrawing groups in the molecule, are suitable as additives during the peptide bond formation. The dissociation constant of some oximes, such as diethyl 2-(hydroxyimino)malonate, ethyl 2-cyano-2-(hydroxyimino)acetate (oxyma), hydroxycarbonimidoyl dicyanide and N-hydroxypicolinimidoyl cyanide in 95% acetonitrile-water are reported.read more

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MAGDA FOUAD FATHALLA ,SHERINE NABIL KHATTAB ,

Synthesis, Crystal Structure and Thermodynamic Properties of the Compound (C10H16NO)2CdCl4·C10H16NOCl·H2O(s)

A novel complex (C10H16NO)2CdCl4·C10H16NOCl·H2O(s) was synthesized by the method of liquid phase reflux synthesis. FTIR, chemical and elemental analysis, and X-ray crystallography were applied to characterize the crystal structure and composition of the complex. The crystal structure of the complex belongs to triclinic system with space group P1 and cell parameters a=0.55703(6) nm, b=1.39937(15) nm, c=1.40559(16) nm; a =117.819(2)°, b =98.8510(10)°, g =96.5770(10)°, respectively. The compound is a salt, which consists of three [C10H16NO]+ cations, a [CdCl4]2- anion, a Cl- anion and a water molecule. On account of electrostatic attraction and four types of intramolecular hydrogen bonds an infinite network supermolecule is formed. Low-temperature heat capacities of the compound were measured by a precise automated adiabatic calorimeter over the temperature range from 78 to 365 K. A polynomial equation of heat capacities against the temperature in the region of (78—365) K was fitted by least square method. Based on the fitted polynomial equation, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated at intervals of 5 K.read more

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DA-QI WANG ,JING-TAO CHEN ,WEN-YAN DAN ,DONG-HUA HE ,ZHEN-PING CHEN ,YOU-YING DI ,

Estimation of Chromium (VI) in various body parts of Local Chicken

Chicken is a common type of meat source in our food. It is fed with the feed containing small pieces of leather having Cr (VI) which persisted in it during chrome tanning process. The core purpose of present study was to determine the concentration of Cr (VI) in different body parts of chicken like leg, arm, head, heart, liver and bone. Estimation of Cr (VI) was done by preparing the sample solutions after ashing and digestion with nitric acid, by atomic absorption spectrophotometer. The results depicted that the meat part of leg had higher mean concentration (1.266 mg/kg) with 0.037 mg/kg standard error while the lowest average concentration was found in arm (0.233 mg/kg) with standard error as 0.019 mg/kg. In case of bones, the maximum mean concentration was found in head (1.433 mg/kg) with standard error as 0.670 mg/kg. The concentration of Cr (VI) was not found similar in meat and bones of chicken by employing Kruskal Wallis Test.read more

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TARIQ MAHMUD ,MUHAMMAD FAROOQ ,ADNAN ALI ,SAKHAWAT ALI ,RABIA REHMAN ,JAMIL ANWAR ,AADIL ABBAS ,

Effect of Saturation and Micro Nutritional Status on Stability of Dietary Oils under Photooxidative Stress Condition

Various commercial fats were photooxidized. Objective test methods i.e., peroxide value (POV), free fatty acid (fFA), anisidine value (AV), iodine value (IV), color index, fatty acid profile radical scavenging activity (RSA) and Chemiluminescence (CL) method  were applied to observe the  changes that take place when lipid is oxidised. Result revealed a significant (P<0.05) positive correlation between change in quality indices and storage conditions. Among the samples Red Palm Oi\l (RPO) showed greater stability as reflected by least 18:2 to 18:1 ratios, balanced fatty acids profile and presences of higher amount of natural antioxidants.The highest Radical Scavenging activity (RSA) was also noted in RPO followed by Vegetable Ghee (VG) and Sunflower Oil (SFO). A proportional positive relationship was observed between physicochemical characteristics of oxidized fats and their RSA while linear response of Chemiluminescence (CL) intensity was found with the increase in POV.read more

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SHAHEEN ATTA ,TAUFIQ AHMAD ,SAEED GUL ,AURANG ZEB ,

Spectrophotometric Assay of Clorazepate Dipotassium in Dosage Forms

A new spectrophotometric method for the determination of clorazepate dipotassium in pure form and in pharmaceutical preparation has been developed. The method is based on the complex formation due to charge transfer between clorazepate dipotassium and alizarin sulphonic acid (sodium salt). The pink coloured complex is obtained after heating the reaction at 50 ºC for 90s. It has maximum absorbance at 530 nm and is stable for more than 24 hours. The reaction obeys Beer’s law from 5 to 250 µg/mL of clorazepate dipotassium with 5 µg/mL as the visual limit of quantitation. The molar absorptivity and relative standard deviation are 0.45 x 104 mol-1 cm-1 and 0.94 %, respectively. The quantitative assessment of tolerable amounts of other drugs not interfering was also studied.read more

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ASRAR AHMAD KAZI ,AMINA MUMTAZ ,MUHAMMAD NAEEM SHAHID ,RABIA NAZIR ,MUHAMMAD USMAN SABRI ,

Synthesis, Characterization and Antioxidant Activity of Ferrocenylhydrazones

Condensation reactions of 1, 1’-diacylferrocenes with hydrazine hydrate afford a series of 1, 1’-bishydrazonoalkylferrocenes. Characterizations were carried out by using IR, 1HNMR, electronic absorption and elemental analysis. Antioxidant activity of the compounds and their precursors was investigated with DPPH·. The result indicated that diacylferrocene derivatives (hydrazones) had certain antioxidant activity, which were enhanced by the increase of compounds concentration, but reduced as the bulkiness of the α-substituent hydrozone group increased. The antioxidant activity of diacylferrocenedizones was much higher than that of precursors (diacylferrocenes)read more

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JIAN ZHANG ,RUIDONG LIU ,