VOLUME 34, NO2, APR 2012

Quantum Mechanical Analysis on Faujasite-Type Molecular Sieves by Using Fermi Dirac Statistics and Quantum Theory of Dielectricity

We studied Faujasite type molecular sieves by using Fermi Dirac statistics and the quantum theory of dielectricity. We developed an empirical relationship for quantum capacitance which follows an inverse Gaussian profile in the frequency range of 66Hz – 3MHz. We calculated quantum capacitance, sample crystal momentum, charge quantization and quantized energy of Faujasite type molecular sieves in the frequency range of 0.1 Hz – 104 MHz. Our calculations for diameter of sodalite and super-cages of Faujasite type molecular sieves are in agreement with experimental results reported in this manuscript. We also calculated quantum polarizability, quantized molecular field, orientational polarizability and deformation polorizablity by using experimental results of Ligia Frunza etal [13]. The phonons are over damped in the frequency range 0.1Hz – 10 kHz and become a source for producing cages in the Faujasite type molecular sieves. Ion exchange recovery processes occur due to over damped phonon excitations in Faujasite type molecular sieves and with increasing temperatures.read more

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M. ASHFAQ AHMED ,SYED MOHSIN RAZA ,SHER AKBAR ,MASOOM YASEEN ZAI ,SALMA JABEEN ,YASMIN ZAHRA JAFRI ,

Decolorization of Direct Dyes Using Peroxidase from Raphanus sativus (F04 SL)

An acidic peroxidase was isolated and partially purified from Raphanus sativus. The purified enzyme was characterized in terms of kinetics and thermodynamic aspects. Finally the enzyme was assessed to see its potential for decolorization of direct dyes. The specific activity of Raphanus sativus peroxidase increased from 44.77 to 65.20 U/mg of protein using 80 % ammonium sulphate precipitation. The optimum pH and temperature of the enzyme was 4 and 55 oC respectively. The activation energy of Raphanus sativus peroxidase was 25.44 kJ/mol and average value of Km was 0.25 mM. The activation energy of thermal denaturation of Raphanus sativus peroxidase was 17.79 kJ/mol. It was observed that with an increase in temperature, there was decrease in a half life and enthalpy, which showed that the enzyme was unstable at higher temperature. A maximum decolorization  of 97 and 77 % was observed for Solar Blue A and Solar Flavine 5G at pH 4 and temperature 50 ºC respectively. It was observed that % decolorization of both the dyes increased with an increase in enzyme units and incubation time. H2O2 dose of 0.8 mM for Solar Blue A and 0.7 mM for Solar Flavine 5G was sufficient for the maximum dye degradation.read more

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AFNAN HABIB ,HAQ NAWAZ BHATTI ,UMME KALSOOM ,

Effect of pH and Temperature on the Catalytic Properties of Manganese dioxide

Manganese dioxide was studied for its catalytic activity under different experimental conditions such as pH (3 -10) and temperature (30 -70oC). Decomposition of hydrogen peroxide is used as an indicator reaction for the catalyst. The kinetics of the reaction was analyzed by first order equation and rate constants were determined from the slopes of the straight lines. It was observed from the experimental results that the decomposition rate constant was found to be dependent on pH and temperature. The high rate constants at high pH values for the decomposition reaction demonstrated the fact that negative surface sites are responsible for the decomposition of hydrogen peroxide. The same trend in the percent decomposition of hydrogen peroxide was observed while using NaNO3 as a background electrolyte. It was further noted that high temperature enhanced the catalytic activity of MnO2. Activation energy for the decomposition reaction at different pH was estimated from the slope of Arrhenius plot.read more

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MURAD ALI ,NAILA KHALID ,KHALIDA AKHTAR ,

Removal of Neutral Red Dye from Water Samples Using Adsorption on Bagasse and Sawdust

The neutral red dye is used in textile and leather industries and in environmental research. Therefore, the removal of this dye from the factory wastewaters is environmentally significant. In this research, two very inexpensive, abundant and easily available adsorbents, i.e. sugarcane bagasse and sawdust, were employed to remove the neutral red from water. The effects of various conditions such as pH, electrolyte concentration, adsorbent dose, contact time and agitation rate were studied for the removal of the dye in a concentration of 100mg L-1. The obtained conditions were applied for various concentrations of the dye (100 – 400 mg L-1) and in all the cases, an efficiency of more than 96 % was attained. Adsorption isotherms were studied which were well in line with both Langmuir and Freundlich equations. The possibility of employing columns was studied and good results were achieved. The method was applied for the removal of dye from real samples of different waters.read more

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HOSEIN FARAJI ,SHAHLA ELHAMI ,MEHDI TAHERI ,

Comparative Study of Different Techniques of Composting and their Stability Evaluation in Municipal Solid Waste

Spatial differences in the physical and chemical characteristics related to maturity of composted organic matter are strongly influenced by composting methods. For evaluation of compost maturity three locally fabricated composters (aerobic, mixed type, anaerobic) processes were examined at seven days interval up to 91 days by loading MSW along with bulking agent. Gradual changes in physico chemical characteristics (temperature, pH, moisture, CEC, humification) related to stability and maturity of compost were studied and compared. Increase in ammonia nitrogen level due to rise in temperature was maximum in aerobic process. Substantial increase in CEC in aerobic process was earlier which leads to establish the optimal degree of maturity as compared to other processes. FA and HI decrease rapidly as composting progressed. Optimal level in stability and maturity parameters like C:N, HA, DH and HR were attained earlier in aerobic process as compared to mixed type and anaerobic processes due to continuous aeration. The parameters (HR, DH, FA, HA), which indicate the compost stability were correlated among themselves. The parameters defining maturity such as CEC, ammonia nitrate and C:N ratio were also related to above mention parameters. The compost from the aerobic process provided good humus and micronutrients. Result from this study will assist in method optimization and quality of the compost product.read more

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MUHAMMAD KHALID IQBAL ,AMANA NADEEM ,RAUF AHMED KHAN ,ANWAR HUSSNAIN ,

LiCoO2 Structures by Spray Pyrolysis Technique for Rechargeable Li-ion Battery

As the lithium-ion batteries have high energy density,  Lithium-batteries have become a very attractive field of study for the  researchers.  Batteries’ high energy density is up to the anode and  cathode materials used in the batteries and the technique which is chosen for getting these materials. In this study,  LiCoO2, used for cathode active material in lithium ion batteries, has been prepared with spraying on a glass base by spray pyrolysis technique. LiCoO2 was annealed at 600C for 3h in an air atmosphere; and crystal structures of the obtained samples were examined with XRD, the surface morphology of them was examined with SEM. Effect of annealing on crystallization has been investigated in prepared samples.read more

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MEHMET YILMAZ ,MEHMET ERTUGRUL ,GUVEN TURGUT ,SERDAR AYDIN ,

A New Resonance Light Scattering Method to Determine Quercetin

The paper established a new resonance light scattering method for determining quercetin content in water solution. It was found that in hexamine buffer solution (pH7.50), sodium-dodecyl-benzene-sulfonate-hexadecyl-trimethyl-ammonium-bromide system can enhance the resonance light scattering intensity of quercetin which is in proportion to the content of quercetin in the range of 2.0×10-9 to 5.0×10-5mol/L. The detection limit is 5.0×10-10mol/L.read more

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JIA ZHEN ,

Optimization of Operational Conditions for Batchwise Biosorption of Chromium (VI) Using Chemically Treated Alstonia scholaris Leaves as Biosorbent

Biosorption has attracted attention as a cost-effective tool for the treatment of metal-bearing wastewater. While using novel biosorbents, optimization of operating conditions becomes more important for the efficiency of the process. In this study, a novel biosorbent i.e. Alstonia scholaris leaves were used for biosorption of Cr (VI) from aqueous media. The effect of various parameters, such as contact time of solution with biosorbent, temperature, pH, biosorbent dose and agitation speed were studied. A comparative study of modification of biosorbent using acid and base was also performed. It has been found that acid treated Alstonia scholaris leaves have greater biosorption capacity as compared to untreated and base treated leaves. Optimum conditions for removing Cr (VI) using acid treated biosorbent were: 0.2 g/50 mL of biosorbent, 50 oC temperature, 15 minutes contact time, 300 rpm stirring speed and 2.0 pH. Langmuir and Freundlich isotherms were also employed to evaluate maximum biosorption capacity of untreated and chemically treated Alstonia scholaris leaves for Cr (VI).read more

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JAMIL ANWAR ,SALIHA MAHBOOB ,RABIA REHMAN ,MUHAMMAD SALMAN ,TARIQ MAHMUD ,

Ultrasound-Assisted Synthesis of Acylals Catalyzed by Stannum (IV) Phosphomolybdate under Solvent-Free Condition

An efficient method for the synthesis of acylals from different aldehydes and acetic anhydride in the presence of Keggin-type stannum (IV) phosphomolybdate under ultrasound irradiation at room temperature was achieved. This method provides a new and efficient protocol in terms of cost effective of catalyst, a wide scope of substrates, and simple work-up procedure.read more

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QING LIU ,HONG MEI AI ,

Statistical Analysis and Quantification of Alpha Tocopherol in Edible Seeds and Nuts of Pakistan by Reversed Phase HPLC with UV/Visible Detector

In present study, alpha tocopherol was determined in different edible seeds and nuts of Pakistani origin by reversed phase high performance liquid chromatography employing UV/Visible detector. Alpha tocopherol is an important constituent of vitamin E. Extraction of sample oil was carried out by Soxhlet method using n-hexane as a solvent. The maximum concentration of alpha tocopherol was found in wheat germs, i.e. 212.5 mg/100 g and minimum in cashews i.e. 0.15 mg/100 g. Almond, peanut, rice bran, corn, canola seeds, walnut, pine nuts and pistachios contained 37.8, 8.8, 3.6, 1.9, 1.6, 0.6, 0.26 and 0.2 mg of alpha tocopherol/100 g of sample respectively. The results show that the adequate amounts of alpha tocopherol are present in edible seeds and nuts, which emphasizes their recommendation in daily routine diet to remove the deficiency of vitamin E in human body.read more

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WAHEED -UZ- ZAMAN ,MEHWISH AKRAM ,JAMIL ANWAR ,RABIA REHMAN ,