VOLUME 37, NO4, AUG-2015

Ultrasound-Assisted Extraction and Characterization of Pectic Polysaccharide from Oriental Tobacco Leaves

Ultrasound-assisted extraction (UAE) of pectic polysaccharide from oriental tobacco leaves was studied by orthogonal matrix method (L9(3)4). Furthermore, the crude polysaccharide was purified and two components (Fr-I and Fr-II) were obtained. FT-IR spectral analysis of the purified EPS revealed prominent characteristic groups. The monosaccharide composition analysis indicated the main composition between Fr-I and Fr-II was different. Furthermore, thermo gravimetric analysis (TGA) indicated the degradation temperature (Td) of the Fr-I (215 oC) was higher than those of Fr-II (162 oC). Detected by the pyrolysis GC/MS, though the main kinds of pyrolysis products from both Fr-I and Fr-II were similar, the larger amount of heterocycle and aromatic compounds liberated after hydrolysis of Fr-II. Finally, On the basis of the antioxidant activity test in vitro, Fr-II has stronger antioxidant activities than Fr-I. The thermal behavior and antioxidant activity might be attributed to the configuration of the sugar units and chemical compositions.read more

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Shaohua Liu, Peixin He, Zhaofu Tian, Xiaolan Li and Chunping Xu

Thermodynamic Parameters Evaluation of - and -cages in Na+, Ba2+, Fe3+, Co2+, Ni2+ and Cu2+ Exchanged Zeolite a Using Quantum Mechanical Theory and Fermi Dirac Statistics

The aim of present paper is to investigate the effects of non-framework cations, their hydration capacity and the role of phonons (acoustical and optical) on the thermodynamic characteristics of Type-A zeolite using Quantum mechanical theory and Fermi Dirac Statistics. This study is motivated by the lack of an accurate measurement capability of thermodynamic properties of zeolites by the existing methods reported in literature, that is why we have suggested the quantum mechanical and Fermi Dirac statistical approaches. Thermal analysis data for zeolite samples were obtained by thermogravimetric and differential thermal analysis (TG-DTG) technique at a heating rate of 10 K min–1 in order to evaluate the desorption behavior of water. The results showed that the thermal stability of these samples was found to be dependent mainly on the electropositive non-framework cations. Meanwhile, on the basis of thermodynamic parameters, the sizes of α- and β-cages in Na-A and its derivative zeolite were calculated using Fermi Dirac Statistics. Thereafter, semi-quantum effects (logarithmic behavior) of specific heat, entropy and enthalpy were observed in all samples as manifestations of the production of phonons due to gaining of thermal energy. As a result, Debye temperature would increase due to localization of heat energy in the Brillouin zone, and the calculated specific heat capacities showed almost no changes after cation exchange. However entropy and enthalpy first exceeds NaA in Ba2+, Ni2+ and Cu2+ and then decrease in Fe3+ and Co2+. These demonstrations indicated that Ba2+, Ni2+, Cu2+ Fe3+ and Co2+ cations influenced both the entropy and enthalpy as a result of the interaction of cations with the zeolite framework, which confirmed that the changes in the lattice mode were dependent on the increase or decrease in the electrostatic interactions between the cations and the framework zeolite.read more

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Hamida Panezai, Abdul Nabi, Mohammad Yaqoob, Nusrat Munawar, Syed Haider Shah and Syed Mohsin Raza

Development of Stable Freeze Dried Kits of 99mTc-Ciprofloxacin for Infection Imaging

Radio-labeled antibiotics are being employed for the particular diagnosis of infections utilizing their specific binding properties to the bacterial components. Stable freeze dried kits of ciprofloxacin is developed through simple stirring at room temperature and labeled with 99mTc after incubation at 35°C.Kits produced through this method showed high stability both at room temperature and in serum at 37ºC. The radiochemical purity of the complex was 99.6% when 1.0 mg ciprofloxacin in the presence of 100.0 μg SnCl2, 2.0 mg gentistic acid, 3.0 mg penicillamine and 20.0 mg d-mannitol was labeled by 10-20 mCi sodium pertechnetate. Serum protein binding, lipophilicity, in-vitro binding with Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli as well as in-vivo biodistribution in infected rabbits were also investigated. Biodistribution results exhibited that radio ligand had good affinity in the infected site in rabbit. The uptake for Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli induced infections as target to non-target ratio (T/NT) 5.425 ± 0.17, 5.397±0.15 and 4.890 ± 0.13 at 1 hr post injection respectively.read more

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Shabnam Shahzad, Muhammad Abdul Qadir and Mahmood Ahmed

Kinetics of the Uninhibited Reaction of 2-Chloropropene-Part II: Comparison with Inhibited Reaction

The kinetics of the uninhibited reaction of 2-chloropropene in the gas-phase has been studied between 662 and 747 K at pressures ranging from 11 to 76 Torr with the object of determining the overall mechanism using static system. The reaction was found to be accurately of the first order at the high pressures and the observed rate coefficient is expressed by the following Arrhenius equation: ktotal uninhibited = 107.98  0.6 (s –1) exp–167  7.8 (kJ/mole)/RT The activation energy was calculated at 167±7.98kJ/mol and identified with the dissociation of C-Cl bond. The reaction is presumed to be unimolecular at lower temperature with formation of propyne and elimination of hydrogen chloride. However, at high temperature C-Cl bond fission takes place and this changes the mechanism of the reaction. Two mechanisms dehydrohalogenation molecular elimination and C-Cl bond fission are discussed.read more

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Jan Nisar, Rameez Razaq and Iftikhar Ahmad Awan

Ozonation of Cephalexin Antibiotic Using Granular Activated Carbon in a Circulating Reactor

A circulating reactor was used to decompose cephalexin during catalytic ozonation. The effect of ozone supply and granular activated carbon (GAC) catalyst was investigated for removal of CEX and COD. The regeneration of exhausted activated carbon was investigated during in-situ ozonation. According to results, ozone supply appeared as the most influencing variable followed by dosage of granular activated carbon. The BET surface area, thermogravimetric analysis (TGA) and temperature programmed desorption (TPD) curves indicated that solid phase regeneration of activated carbon using ozone gas followed by mild thermal decomposition was very effective. The adsorption capacity of regenerated activated carbon was slightly lower than virgin activated carbon. The overall study revealed that catalytic ozonation was effective in removing cephalexin from solution and the method can be applied for in-situ ozonation processes.read more

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Javaid Akhtar and NorAishah Saidina Amin

Theoretical Investigation on Structures and Nonlinear Optical Properties of the Alkalis and Low Coordination Acenes Salt

The alkalis and low coordination acenes salts α-M@n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) were designed to investigate the effect of the increasing atomic number of alkali metals and the number n of conjugated benzenoid rings on the nonlinear optical responses. Alkalis Li, Na and K were selected herein, and both DFT (M05-2X, M06-2X and PBE0) and MP2 methods and 6-311+G(D) basis set are employed to optimize geometrical structures and to calculate the polarizability (α0) and first hyperpolarizability (βvec) of the α-M@n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3). Results show that the α0 values of α-M@n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) increase with increasing number of n conjugated benzenoid rings and the atomic number of alkali metals and βvec values of α-M@n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) are opposite. The βvec values of α-M@n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) are inceasing remarkably (397.6 au. for α-Li@ benzene < 1196.5 au. for α-Na@benzene < 1608.6 au. for α-K@benzene and tending to decease with increasing number of n by M06-2X method. Our present research may be favorable to the development of excellent nonlinear optical (NLO) materials.read more

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Wenmin XIAO and Dongmei LUO

Thermal Analysis and Degradation Kinetics of Dextran and Highly Substituted Dextran Acetates

Dextran acetates were synthesized to study their thermal behavior in comparison with pure dextran. The results have indicated that dextran is significantly stabilized after acetylation. Dextran acetates are thermally 65-74 °C more stable as compared to pure dextran in terms of maximum decomposition temperature (Tdm). Likewise, degradation of dextran acetates also starts and ends later than dextran as shown by relatively higher initial (Tdi) 3-33 °C and final decomposition temperature (Tdf) 55-69 °C. The dextran acetates can be arranged in increasing order of thermal stability: dextran acetate DS 2.91 < dextran DS 2.98 < dextran acetate DS 3. The activation energy (Ea) of dextran and dextran acetates was calculated with the help of Friedman, Broido and Chang kinetic models while order of reaction (n) was calculated from thermal data using Chang and Kissinger models. Several other important parameters were also calculated including frequency factor (Z), enthalpy (∆H), Gibbs free energy (∆G) and entropy (∆S). The integral procedural decomposition temperature (IPDT) and comprehensive index of intrinsic thermal stability (ITS) was also drawn from TG curves using Doyle’s method. The dependence of IPDT, ITS and Ea on DS of the acetylation of dextran is also discussed.read more

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Muhammad Amin, Muhammad Ajaz Hussain, Dure Shahwar and Mazhar Hussain

Cloud Point Extraction Using Tergitol TMN-6 of Gold(Ш)in Real Samples by Flame Atomic Absorption Spectrometry Determination

A simple, safe and rapid method on the basis of cloud point extraction(CPE) with tergitol TMN-6 had been used for the preconcentration and extraction of gold(Au) ion in selenium reduction solution sample prior to flame atomic absorption spectrometry (FAAS).Pyrrolidine dithio fromic acid salt(PDFAS)which was regarded as a selective complexing agent could formed stable Au-complex with Au ion, and Au-complex could be extracted by TMN-6 at a short time. Some influencing factors such as sample pH, concentration of TMN-6, concentration of PDFAS and the effect of foreign ions were further researched .Under the optimum conditions, the limit of detection(LOD) was 1.3μg L-1,the calibration graph was linear in the range of 0-500μg/L and the relative standard deviation(RSD%) was 2.0%(n=8). The CPE method had been shown to be a useful and effective methodology for the separation of Au, with a preconcentration factor of 30. The recoveries of the spiked Au(Ⅲ) ions were got in the range 95–103%.read more

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Xuan Zhou, Pingyan Wang, Yu Zhao, Shuangqiao Ju and Mousheng Liu

Cerium Modified Pillared Montmorillonite Supported Cobalt Catalysts for Fischer Tropsch Synthesis

Fischer-Tropsch (FT) synthesis was accomplished over Al-pillared Montmorillonite supported 20 wt% Co modified with different weight% of cerium catalysts. These catalysts were prepared by impregnation method while structural characterizations of the prepared samples were performed by XRD, TPR, NH3TPD, TGA, BET, XRF and SEM techniques. The Fischer Tropsch reaction was studied in fixed bed micro catalytic reactor at temperature range of 220, 260 and 275 oC and at different pressure (1, 5, and 10 bars). From the activity results, it was found that by pillaring NaMMT with Al higher catalytic activity and lower methane selectivity of NaMMT was achieved. Furthermore, the results of FT synthesis reaction revealed that cerium incorporation increased the dispersion of Co3O4 on the surface and consequently resulted in enhanced catalytic activity. Additionally, the C5-C12 hydrocarbons and methane selectivity increased while C22+ hydrocarbons selectivity was decreased over cerium modified catalysts. Higher reaction temperature (>220 oC) resulted in significant enhancement in CO conversion and methane selectivity. Though, increase in pressure from 1 to 10 bars eventually resulted in increase in C5+ hydrocarbons and decrease in methane and C2-C5 hydrocarbons selectivity.read more

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Nisar Ahmad, Zulfiqar Ali, Nisar Ali, Naeem Shahzad, Fida Hussain, and Syed Mustansar Abbas

Characterization and Exergy Analysis of Triphenyl Borate

In this study, unlike from the literature, boron oxide, borax decahydrate, boric acid and borax pentahydrate as boron sources were used to synthesize Triphenyl Borate (TPB). The reactions of TPB were carried out by using both phenol and various boron sources in inert water-immiscible organic solvent successfully. On the basis of analyzes (FT-IR, SEM, TGA/DSC) obtained, it was seen that phenol acted as a support to borate structure framework and thermal characterisation of the amorphous solid under determined conditions suggested that usage of different boron sources had effects for glass transition temperature in TPB production. The exergy analysis was performed to the TPB production to determine efficiency. The exergy analysis showed that the highest exergy efficiency was obtained by using boron oxide as a boron source. Consequently, all analyses results showed that TPB was produced successfully. Accordingly, characterization and exergy analysis supported each other.read more

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Nil Baran Acarali