VOLUME 33, NO2, APR 2011

Kinetic and Equilibrium Studies for Zn (II) and Cu (II) Metal Ions Removal Using Biomass (Rice Husk) Ash

Heavy metal ions have the severe hazardous effects on human health even were present in traces in waste water. Conventional methods are not economical for the removal of low level concentration of these ions. The present research reports the adsorption of Cu and Zn ions from aqueous solutions at low concentration range (5-100 mg/L) in batch systems using Rice Husk Ash as an adsorbent, which is abundantly available as agricultural waste. The present study emphasizes on the experimental development of the optimum parameters such as equilibrium time, pH and initial concentration. Equilibrium data obtained have been fitted to the Langmuir, Freundlich, Tempkin and Dubinin - Radushekevich (DR) adsorption isotherms.  Freundlich isotherm best fits the experimental results. Kinetic modeling of first order and pseudo-second order showed that the pseudo-second order equation was the most appropriate for the description of Zn (II) and Cu (II) adsorption by Rice Husk Ash.read more

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ASMA KHAN ,NADEEM FEROZE ,NAVEED RAMZAN ,IZZAT IQBAL CHEEMA ,

Raw Mix Designing for Coal as a Fuel in Cement Kiln as a Major Fuel and its Impact on Clinker Parameters

In this paper the use of coal, found at Jabba Taar and Jabba Khushk Khyber Pakhtoon Khwa, in cement manufacturing as a major fuel and its impacts on the raw mix and clinker parameters has been discussed. The maximum amount of coal for pulverizing with raw mix was found to be 10%`of the raw mix as calculated from the calorific value and the heat of clinkerization of coal. The coal residue left after burning was utilized in the cement raw material, for which a new raw mix was designed. The new raw mix was converted in to clinker. The resulting clinker was studied for all parameters as per British specification. It was found that the clinker obtained from the newly designed raw mix with coal ash, was in accordance to the British standard specificationsread more

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NOOR -UL- AMIN ,KHURSHID ALI ,

Electrode Surface, Fractal and Heterogeneous Electron Transfer Rate Constants

Impedance and cyclic voltammetric studies, were carried out on electrodes of various material, dimension and configuration. The substrate was ferrocene.  This was done with the view to explore the relationship between heterogeneous electron transfer rate constants (ko) of ferrocene and various fractal parameters. It was found that the best relationship was obtained between the magnification factor fm and ko, implying that electrodes behave as cantor sets, and “grooves” in an electrode affect the electron transfer process.read more

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MAHBOOB MOHAMMAD ,

Kinetic and Thermodynamic Studies of Indigo Adsorption on some Activated Bio-Solids

The performances of five activated bio-solids adsorbents on adsorption of Indigo from its dyeing effluent were studied using their thermo-kinetics equilibrium data. The results were compared with the commercial powder carbon as standard. The adsorbents were prepared from cattle bone carbon, algae carbon, water lettuce carbon, elephant grass carbon and crab shell carbon. The activated cattle bone has the highest monolayer adsorption capacity among the bio-solids. The adsorption kinetics of all the adsorbents conformed to the pseudo-second order kinetics, with good correlation.  Also, the thermodynamics parameters of the adsorption process fitted very well with the experimental data. The standard Gibb’s free energy change (ΔGo) for all the adsorption reaction was negative, indicating the spontaneity of the process.read more

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JAMIU MOSEBOLATAN JABAR ,ABAYOMI OLAGUNDOYE ADETUYI ,

Prospects of Sea Water Electrolysis for the Production of Hydrogen: An Exploratory Study on the Electrolysis of Magnesium Chloride Solution in the Presence of Sulfur

It was hypothesized that the use of sulfur powder or sulfur electrode in the sea-water electrolysis would prevent (i) chlorine evolution, (ii) precipitation of Mg(OH)2 and would at the same time result in the production of H2SO4, which might facilitate evolution of H2. The hypothesis was tested with MgCl2 solution as representative of sea water and using Pt, graphite, carbon felt working electrodes with sulfur powder and “sulfur” electrodes as working electrodes. Experimentally it was found that on the addition of sulfur or the use of a sulfur electrode (as anode), chlorine evolution was prevented on anode and Mg(OH)2 precipitation was prevented on cathode and at the same time H2SO4 was produced. H2 evolution, though confirmed, however, could not be quantitatively collected.read more

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MAHBOOB MOHAMMAD ,MICHELLE KAUKHAB ,

Comparative Study of the Impact of Different Additives on Cementing Properties of High Strength Portland Cement

In this study Methylmethacrylate and Ethylenediammine have been used as additive in high strength Portland cement and its impact on the cementing properties (water of consistency, setting time and hydration behavior i.e., combined water at different curing times; 3, 7 and 28 days) has been studied. Different doses (1, 2, 3, 4 and 5 %) of methylmethacrylate (C5H9O2) and ethylenediammine (C2N2H8) were added to high strength Portland. Results indicated that methylmethacrylate acts as a setting retarder with increasing water of consistency, it has a negative effect on  hydration properties, however when present in limited content (not more than 2 %) its negative effect is relatively slight. On the other hand, ethylenediammine acts as a water reducing and setting accelerator agent, its addition up to 3 % results in a remarkable improvement in the above-mentioned propertiesread more

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SABIHA SULTANA ,NOOR -UL- AMIN ,

Assessment of Dissolved/ Dispersed Aliphatic and Aromatic Hydrocarbon Pollution in Seawater at the Clifton Beach on the Karachi Coast

Sea water samples collected at different depths from 10 stations along the Clifton beach of Karachi Coast were analyzed for dissolved/dispersed polyaromatic and aliphatic hydrocarbons (PAHs and AHs) by GC and GC-MS. Sampling was performed in august 2003, just after the Tasman Spirit oil spill and in august 2003. Levels of total polycyclic aromatic hydrocarbon (PAHs) and aliphatic hydrocarbons (AHs) were 8.20-26.35 µg L−1 (Σ 16 PAHs) and 5.23-21.005 µg L−1 (Σ 16 AHs), respectively. Values decreased later on till lower than 0.02-0.25 ug L−1 possibly representing the background level of the region, exhibited lower concentrations that ranged from 0.02-0.05 µg L−1 (Av. 0.15 µg L−1  Σ 16 PAHs and 0.05–0.2 µg L−1 Σ 14 aliphatic hydrocarbons) with decreasing to 0.07 µg L−1 of PAHs with depth in the water. In September 2005, the concentrations were rather uniform, averaging 0.05 µg L−1  (Σ 16 PAHs) and 4.08 µg L−1 Σ 14 aliphatic hydrocarbons.read more

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FAYYAZ AHMED ANSARI ,SOHAIL SHAUKAT ,MOHAMMAD FAISAL KHAN ,HINA AHSAN ,ALIA BANO MUNSHI ,

Variation in Composition and Yield of Foliage Oil of Eucalyptus Polybractea

Eucalyptus polybractea (blue mallee) is the essential oil rich species used in the commercial production of pharmaceutical-grade Eucalyptus oil in Australia. This species was grown at Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan during 2004-08 to investigate the quantity and quality of its foliage oil. The oils were extracted by hydro-distillation method, from the leaves of four year aged ten E. polybractea plants. The data showed a significant intra-species variation in their oil contents (29.3 to 41.8 mg g-1 fresh weight of leaves). Out of ten plants eight contained oil >30 mg g-1 fresh weight of leaves. The components of the extracted oils varied from 12-26 as detected by GC/FID on Carbowax 20 M packed glass column.  Among all the oil components, 1, 8-cineole was the major compound (91.7–94.2 %), while the other identified compounds were a-pinene (0–1.2 %), β-pinene (0.4­–2.3 %), limonene (0.2–1.3 %), p-cymene (1.23–2.75 %), and terpinene-4-ol (0.6–0.92 %). The extracted oils from all the Eucalyptus polybractea plants contained high amount of 1, 8-cineole (>90 %), therefore, classified as species of high quality medicinal oil.read more

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MUHAMMAD AKHTAR ,RASHID AHMAD ,TARIQ MAHMOOD QURESHI ,ZAFAR IQBAL ,JAVED AKHTER ,

Spectrophotometric Quantification of Antioxidant Phytochemicals in Juices from Four Different Varieties of Citrus limon, Indigenous to Pakistan

This research work was carried out to quantify the total phenolics, flavonoids and carotenoides, vitamin C contents, reported as antioxidants, in juices of four varieties of Pakistani Citrus limon. Juice was extracted from fresh lemon samples using classical method and subjected to study the various quality parameters. The total phenolic contents from juices of Citrus limon, determined following the Folin-Ciocalteu assay were found in the range of 690.62–998.29 mg/L, showing the significant inter-varietals variations. The total flavonoids and vitamin C contents from juices of Citrus limon were found in the range of 211.36–220.34 and 18.87–25.1 mg/L, respectively. Whereas, the total carotenoides contents of Citrus limon juices were found in a low concentrations i.e. 0.05–0.08 mg/L. The statistical analysis showed significant (p < 0.05) variations in the total phenolic, carotenoides and vitamin C contents while non-significant (p > 0.05) variation in total flavonoids contents among different varieties of Citrus limon.read more

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ABDULLAH IJAZ HUSSAIN ,MUHAMMAD KALEEM KHOSA ,SHAHZAD ALI SHAHID CHATHA ,KHALID MAHMOOD ZIA ,HIBA RIAZ ,KINZA ASLAM ,

Lead Application for the Stimulation of Fusaricidin Type Compounds by Paenibacillus polymyxa SQR-21

Paenibacillus polymyxa strains produce fusaricidin type compounds that are active against a wide variety of Gram-positive bacteria and fungi. Growth and production of fusaricidin type antifungal compounds by P. polymyxa SQR-21 were compared in tryptone broth supplemented with three concentrations (200, 400 and 600 µM) of lead. The data revealed that the growth of P. polymyxa increased by 7-34 % and fusaricidin type compounds production increased by 15-70 % with the increase in concentration of lead ion (Pb2+). The increase in Pb2+ concentration, decreased the intracellular carbohydrate contents but increased the intracellular protein and lipid contents, however, higher levels of Pb2+ inhibited the intracellular protein and lipid contents. On the other hand, extracellular protein contents were decreased and extracellular polysaccharide contents were increased with the increase in Pb2+ contents in liquid culture. In addition, the regulatory effects of lead were also reflected by decrease of total RNA and increase of relative expression of the six module-containing nonribosomal peptide synthetase (FusA) when the lead treated experimental samples were compared with the untreated controls. The Pb2+ seems to be directly or indirectly correlated with the production of fusaricidin type antifungal compounds. This information will aid in developing fermentation technology for maximum antibiotic production.read more

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HONGSHENG WU ,SHEN QIRONG ,YANGCHUN XU ,WASEEM RAZA ,