Uranium – The Element: Its Occurrence and Uses

Uranium metal and its compounds have been of great interest to physicists and chemists due to its use for both civil and military applications, e.g. production of electricity, use in the medical field and for making nuclear weapons. This review paper describes the occurrence, chemistry and metallurgy of the element ‘uranium’, its conversion to stable compounds such as yellow cake, uranium tetrafluoride and uranium hexafluoride and the enrichment technologies and uses for both civil and military purposes. The paper is meant for ready reference for students and teachers in connection with the recent spate of interest shown in nuclear power generation in Pakistan and abroad.read more

Iqra Zubair Awan

Production of Activated Carbon from Raw Date Palm Fronds by ZnCl2 Activation

Annually a large volume of date palm frond waste is produced in Saudi Arabia as a result of the pruning of date palm trees. In this research activated carbon (AC) was prepared from date frond through a single step chemical activation method by ZnCl2. The influence of ZnCl2 concentrations (in the range of 0, 20, 40, 60 and 80%) on the surface areas, pore volumes and carbon yield of ACs prepared from raw date frond (RDF) was studied with various analytical techniques. The RDF and ACs were characterized by Thermogravimetric Analysis (TGA), nitrogen adsorption Brunauer-Emmett-Teller (BET) for surface areas and pore volumes, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) for surface morphology and elemental composition respectively. In the present study we have obtained the highest BET surface area 1581.67 m2g-1 and total pore volume 0.629 cm3g-1 at 60 % ZnCl2 concentration. The % yield of ACs increased with increase in ZnCl2 concentration and reached to 39% at 60 % ZnCl2 concentration. The surface area obtained in the present study is highest amongst the results report in literature.read more

Ashfaq Ahmad, Hassan Mohammed Al-Swaidan and Ahmad Hamed Alghamdi

Removal of Hg (II) from Aqueous Solution on Powdered Coal-Based Activated Carbon: Experimental Design of Microwave Assisted Preparation, Equilibrium and Kinetic Study

Preparation of activated carbon from anthracite through microwave-assisted activation was optimized by response surface methodology (RSM). The satisfactory conditions were obtained as follows: 693 W of microwave power, 10 min of irradiation time and 1:1 of the ratio of KOH to coal, and the corresponding adsorbance of iodine and methylene blue (MB) were of 799.32 and 132.03 mg/g, respectively. The production was characterized using nitrogen adsorption isotherm, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR). The resultant powdered activated carbons were applied for removing Hg(Ⅱ) from aqueous solution at different dosage of activated carbon, concentrations of Hg(Ⅱ), adsorption temperature and pH. The Langmuir isotherm was excellently correlated to equilibrium data of Hg(Ⅱ) adsorption, showing Langmuir adsorption capacities of Hg(II) was 145.41 mg/g.read more

Deqiang Li, Xinfang Ma, Jiayu Yan, Zhansheng Wu and Zhiyong Liu

O2-Binding Abilities and Catalytic Oxidation Performance of Cobalt (II) Complexes with Dihydroxamic Acid Functionalized N-pivot Lariat Ethers

The oxygenation constants (InKO2) and thermodynamic parameter (ΔHo, ΔSo) of Novel Co (II) complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL1~CoL4 and the uncrowned analogue CoL5 were measured. Their catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) was investigated. The enhancement of O2-binding and catalytic oxidation activities by the oxa aza crown ether ring of the cobalt complexes as well as the complexed alkali metal and alkaline-earth metal ions were discussed.read more

Liang-Jun LONG, Xing-Yue WEI, Xing-Min WANG and Ning LI

Electrical and Thermal Properties of Glass Matrix-Al2TiO5 Composites Prepared at Low Temperature

In this research, the electrical and thermal properties of glass matrix composites filled with different amounts of aluminium titanate (Al2TiO5) powder varying from 5 to 15 wt. % have been investigated. In order to optimize the processing route, some sintering strategies were tested. The densest specimens were obtained by less pressure of the sintering. The composites were characterized by means of SEM micrography, X-ray diffraction (XRD), differential thermal analysis (DTA), dilatometry and impedance spectrometry. XRD results showed that the main crystallization phases were Wollastonite, Aluminium titanate, Rutile, and Alumina in all sintered glass matrix composites. It was also revealed that addition of 15 wt.% aluminium titanate has increased the relative density and decreased thermal expansion coefficient (TEC) (6.9×10-6/ºC) and electrical conductivity (3.1×10-4 Ohm.cm) in comparison with other composites. The results would be explained considering nature and concentration of the formed crystalline phases and their micro-structures.read more

Maryam Kargar Razi, Reza Tayebee, Atusa Ahmadi and Parvin Alizadeh

Hydrogels for Immobilization of Trypsine Based on Poly-N-vinylpyrrolidone and Arabinogalactan Graft Copolymers

By studying cross-linking of poly-N-vinylpyrrolidone [Mn=1×104 and 4×104] with N,N`-methylene-bis-acrylamide there were obtained water-swelling gel-forming polymers. Also was studied immobilization process of trypsin in polymer gels and Co(II), Cu(II), Ni(II) metal gel-complexes in polymeric gels. It was found that the amount and activity of immobilized trypsin gel carriers based on poly-N-vinylpyrrolidone less compared to the amount and the activity of immobilized trypsin gel carrier cross-linking copolymer of N-vinylpyrrolidone with arabinogalactan from cherry gum. The immobilization mechanism of trypsin into polymer gels investigated by FTIR and 1H NMR spectroscopy.read more

Shamo Zokhrab Tapdiqov, Nizami Allahverdi Zeynalov, Dilgam Babir Taghiyev, Saadat Faik Humbatova, Samira Mirali Mammedova, Elnara Fakhraddin Nasiyyati and Dilshad Talib Babayeva

Synthesis, Characterization and Adsorption Studies of Sulfonated Poly(Styrene)

Poly(styrene) was synthesized by suspension polymerization of styrene. Molar mass of poly(styrene) was determined by viscosity method. Sulfonated poly(styrene) was synthesized by direct sulfonation of poly(styrene) at 40C. These products were identified by using IR spectroscopic technique. Cation exchange properties of sulfonated poly(styrene) have been determined for some metal ions such as Ni2+, Zn2+, Cu2+ and Ca2+. The distribution co-efficient and apparent adsorption capacities show that selectivity order of the metals as follow: Ni2+ > Zn2+ > Cu2+ > Ca2+. It was found that by increasing the pH of solution, the distribution Co-effecients (Kd) value also increased.read more

Muqaddas Saleem, Farah Kanwal, Muhammad Imran and Liviu Mitu

Synthesis and Application of 3-(4-Hydroxyphenylimino)indolin-2-one as Corrosion Inhibitor

A isatin Schiff base, 3-(4-hydroxyphenylimino)indolin-2-one, was synthesized and analyzed by NMR and MS. The inhibition and the mechanism of the title compound on the corrosion of high protective Q235A steel in HCl solution were screened and discussed. The results indicated that it can inhibit the corrosion with moderate inhibition efficiency in different conditions, and the inhibition mechanism of the corrosion inhibiting may be mainly contributed to the adsorption. Potentiodynamic polarization studies indicate that extracts are mixed-type inhibitors. While the title compound was companied with hexamethylenetetramine (HMTA) and 1,4-dihydroxy-2-butyne (BOZ), the inhibition efficiency was enhanced effectively.read more

Hua-Rui Hao, Wei Zhao, Jie Zhang, Yan-Qing Miao and Zhi-Fang Zhang

Phosphotungstic Acid Catalyzed One-Pot Synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines in Aqueous Media

In this study, we report the one-pot synthesis of 2-amino-3,5-dicarbonitrile-6-thio- pyridines with benzaldehyde, malononitrile, and thiophenol by using phosphotungstic acid as an efficient catalyst in aqueous media. This method has the advantages of easy separation, high storage stability, and environmental friendliness.read more

Miao Shen Su, Xiao Jing Ji, Bing Bing Zhao, Meng Tian and Jing Jun Ma

Synthesis, Characterization, Theoretical Calculations and Anti-Tumor Study of 2-Aminopyridine trifluorotitanium (IV) complex

A new titanium compound that is 2-Aminopyridine trifluorotitanium (IV) complex was synthesized and identified. This Complex was prepared through the reaction of 2-Amino pyridine and titanium tetrafluoride salt of in acetonitrile. Identification and Characterization of complex was performed by elemental analysis and spectroscopic methods. Structural and spectroscopic study of the mentioned complex was carried out at DFT- B3LYP/6-311G level of theory. This new compound was used to biological studies; and its anticancer properties against the two types of cancer cells such as k562 (human chronic myeloid leukemia) and Jurkat (human T lymphocyte carcinoma) was revealed.read more

Fahmideh Shabani, Saeed Jameh Bozorghi and Mozhgan Sheykhpoor