VOLUME 39, NO4, AUG-2017
123
 
Tribute to Professor Atta-Ur-Rahman, FRS (75th Birthday of Man of Thousand Attributes)

Muhammad Iqbal Choudhary

Dedicated to Professor Dr. Atta-ur-RahmanFRS, a great teacher, a great mentor, and great patriot, on his 75th Birthday, 22nd September 2017.
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The Purification of Coal Tar by the Addition of Quinoline and Zn(OH)2

Ping Zhou, Qian-lin Chen, Xian-quan Ao, Yan Xie and Chao Kang

The coal tar was purified by the addition of quinoline and Zn(OH)2, in order to decrease the content of carbon and inorganic oxide particles. The effect on the viscosity and ash content of the coal tar were investigated by altering temperature, time, and the amount of quinolone and Zn(OH)2 . When the volume ratio between quinolone and coal tar was 20:1 and the static time was 24 h. The viscosity of three layers decreased with rising temperature. When the static temperature and time was 45 °C and 24 h, respectively. The viscosity of three layers decreased with the arising amount of quinoline. And when the volume ratio between quinolone and coal tar was 20:1 and the temperature was 45 °C. The viscosity of three layers decreased first and then increased with the prolonging of static time. And when the static time of coal tar was 24 h, the viscosity of coal tar is the lowest. Because of the lower viscosity of coal tar, decreasing the content of carbon and ash particles in upper and middle layer, the ash content decreased from 0.168% to 0.092%. The addition of Zn(OH)2 can lead ash content in middle layer decrease to 0.058%. Zn2SiO4 and ZnAl2O4 may be produced due to the reaction between Zn (OH) 2 and SiO2 or Al2O3, which can settle down easily. The results show that the content of carbon and inorganic oxide particles in upper-middle-class (the middle 4/5 of the whole volume) decreased with the addition of quinolone and Zn(OH)2 . When the volume ratio between quinolone and coal tar was 50:2, quality ratio between coal tar and Zn(OH)2 was 20000:1, the mixture were heated up to 45 °C at atmospheric pressure and keeping this constant temperature for 24 h, the ash content in upper-middle-class can decreased to 0.058%.
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Electrochemiluminescence Detection of o-aminophenol Based on PAMAM/CdSe QD/β-CD Modified Electrode

Chao Li, Kun Zhang, Fang Liu, Ling Xing and Jun Wan

A stable and sensitive electrochemiluminescence (ECL) detection protocol of o-aminophenol was developed, which was based on CdSe quantum dots (QDs) and the cavity structure of β-cyclodextrin. In this experiment, the working electrode was prepared by PAMAM and CdSe QD and β-cyclodextrin using layer self-assembly method under the infrared lamp. Under the optimum conditions, a good linear relationship with the concentration of o-aminophenol from 1.0 × 10-7 mol•L-1 to 8.0 × 10-6 mol•L-1 and the detection limits as low as 2.3 × 10-8 mol•L-1 (3σ) were achieved. Good selectivity and repeatability are advantages of the sensor which is feasible.
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Kinetics of Dimerization of the Reduced Products of Methyl Viologen Dication

Lubna Naz and Mahboob Mohammad

The rate constants for the dimerization of the reduced products of methyl viologen dication (MV2+) of the processes (a) methyl viologen cation radical (MV+•), (MV2+ MV+•) and 2MV+• (MV+•)2 and (b) methyl viologen neutral (MV), (MV+• MV) and 2MV (MV)2 were obtained through linear scan- / cyclic- voltammetry and the use of Olmstead-Hamilton-Nicholson theory. The rate constants for the two dimerization processes are reported here. Rate constant for the dimerization process (b) above, of the novel species methyl viologen neutral is being reported first time.
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Determination of Lanthanides in Fossil Samples Using Laser Induced Breakdown Spectroscopy

Jesús-Manuel Anzano, Jaime Cajal, Roberto-Jesús Lasheras, Miguel Escudero, Ignacio Canudo, Mariano Laguna, and Jamil Anwar

As being a fast, simple and relatively non-destructive analytical technique Laser-induced breakdown spectroscopy (LIBS) has a large variety of applications including the analysis of paleontological samples. In this work LIBS is employed for the quantitative determination of lanthanides (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Sm, Tb, Tm and Yb) in vertebrate fossil samples comprising teeth, disarticulated complete or fragmented bones, eggshell fragments, and coprolites of dinosaurs, mammals and crocodiles. For emission line data, standard AnalaR grade salts of lanthanides were used. The major components: iron, calcium, magnesium, silicon and aluminum in the samples were also determined. The analytical information may be helpful in studying the samples for their age, formation environment and other paleontological properties.
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Synthesis of Two 1,3,4-thiadiazole Compounds: Crystal Structure, Theoretical and Antifungal Activity Study

Qiao Wang, Zhong-Hua Shen, Zhao-Hui Sun, Jian-Quan Weng, Cheng-Xia Tan, Xing-Hai Liu and Yong-Gang Zhang

Two novel 1,3,4-thiadiazole compounds, C15H10N4S2 (5a) and C18H19N3S2 (5b) were designed and synthesized by reactions of key intermediate 5-(pyridin-4-yl)-1,3,4-thiadiazole-2-thiol and two substituted benzyl chloride (4-t-Bu and 3-CN). The two 1,3,4-thiadiazole structures were confirmed by 1H-NMR, MS , elemental analyses and X-Ray diffraction. Compound 5a is triclinic with space group P-1 and cell constants: a = 6.1426 (7), b = 8.5323 (14), c = 13.840 (2) Å, α = 90.199 (12), β = 90.002 (11), γ =106.762 (13)°, Dc = 1.484 g/cm3, Z = 2, V = 694.52 (17) Å3, the final R = 0.0400 and wR = 0.111 for 1786 observed reflections with I > 2σ(I). Compound 5b is triclinic with space group P2(1)/c and cell constants: a = 10.490 (5), b = 19.818 (10), c = 8.825(5) Å, α = 90, β = 98.989(10), γ =90°, Dc = 1.252 g/cm3, Z = 4, V = 1812.2(16) Å3, the final R = 0.0630 and wR = 0.192 for 2023 observed reflections with I > 2σ(I). Theoretical calculation was carried out by DFT method using 6-31G basis set. The compounds also possessed moderate fungicidal activity.
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Fe Extraction from Çayeli Copper Ores by Bioleaching with Eco Freiendly Acidithiobacillus ferrooxidans

Mustafa Engin Kocadagistan, Yalçın Kemal Bayhan and Avni Çakıcı

Recently, biological treatment; an important recovery process, has became important from the environmental and economical respects in recovery of metallic values from low-grade sulfur-bearing ores or concentrates. Bacterial ore leaching can be applied to extract heavy metals from low grade ores, industrial wastes and other materials on an industrial scale by different procedures. The main objective of this work was to investigate the dissolution of Fe from Çayeli copper ores, via a bioleaching process using Acidithiobacillus ferrooxidans. Experiments performed with batch operation in jar test equipment were conducted at different pH values, pulp densities, inoculum volumes, particle sizes, stirring conditions and operation times. The optimal parameters were found as follows; at pH 2, the pulp density; 4% (w/v), inoculum volume; 4% (v/v), stirring rate; 120 rpm and particle size; -0.053 mm for 192nd and 288th hours, at pH 2, the pulp density; 4% (w/v), inoculum volume; 5% (v/v), stirring speed; 200 rpm and particle size; -0.053 mm for 384th and 480th hours. By performing the bioleaching process under these conditions, almost 99% of the iron extent in the ore was transfer from ore into solution, however the experiments in which distilled water was used instead of modified 9K*, only 18.5% Fe efficiency was obtained.
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Co(II), Cu(II) and Zn(II) Complexes of N,O-Type Schiff Base Ligand Derived from 4,4′-Methylenedianiline Synthesis, Characterization, Antibacterial and Antifungal Studies

Hakan Şahal, Erdal Canpolat, Mehmet Kaya and Seher Gür

Three new complexes were prepared reacting Co(II), Cu(II) and Zn(II) salts with 2-[(E)-{[4-(4-aminobenzyl)phenyl]imino}methyl]-6-ethoxyphenol (LH) and characterized by analytical and spectrocemical methods. The metal:ligand stoichiometric ratio is 1:1 in the complexes of Co(II) and Zn(II), whereas in the Cu(II) complex, the metal:ligand stoichiometric ratio is 2:1. It was determined that bidentate behavior of the ligand is accomplished via the phenolic oxygen and the azomethine nitrogen atoms. The presence of water is revealed by thermograms and supported by the presence of relevant bonds in their IR spectra. These new complexes showed a reasonable amount antifungal activity.
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Synthesis and Characterization of Commercial Grade Energetic Materials using Decanted 2,4,6 Tri-nitrotoluene (TNT)

Muhammad Farooq Ahmed, Arshad Hussain and Abdul Qadeer Malik

2, 4, 6 Tri-nitrotoluene commonly known as TNT is one of the safest and most widely used energetic material for both military as well as commercial purposes. During Second World War, a huge quantity of TNT was used for filling of various conventional munitions used against adversaries. Resultantly, large numbers of unserviceable munitions were left unused and were either disposed of through conventional disposal techniques such as open burn open detonation, sea dumping, incineration, biological degradation or buried underground without proper disposal. A number of accidents have been reported during disposal of these unserviceable and unwanted munitions. To avoid such a detrimental situation, global efforts were made in the past for re-use of unwanted energetic materials but still a lot more effort is needed in this regard. The present work is aimed at the safe conversion of decanted TNT into commercial grade energetic material which can be utilized for mining, quarrying, underwater blast activities. For this purpose, various materials / ingredients have been used with decanted TNT for the synthesis of newly formed melt cast commercial grade energetic material. This particular sample has further been characterized through Thermo gravimetric/ Differential Thermal Analysis (TG/DTA), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD) techniques for the identification of various aspects. Results show that the newly synthesized sample has a clear, compact and smooth morphology with almost negligible numbers of cracks and pores unlike decanted TNT in unserviceable state. This process of synthesis and reutilization is not only safe and economical but also environment friendly.
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Atmospheric Corrosion Resistance of Epoxy Duplex Coated Electrogalvanized Steel Exposed in Marine, Industrial and Urban Sites at Pakistan

Humaira Bano, Azhar Mahmood and Syed Arif Kazmi

An epoxy based duplex coating system (Electrogalvanized Mild Steel/Etch Primer/Epoxy-Polyamide Primer/ Epoxy-Amine Topcoat System) embedded with iron oxide, zinc chromate and titanium dioxide pigments was studied to ascertain its corrosion resistant synergistic performance at various anthropogenic sites of Karachi coastal city while salt spray test was also executed for reference. Coating performance was ascertained by visual morphological inspection, gloss measurements, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX) analysis and by Fourier Transform Infrared (FTIR) Spectroscopy. SEM & EDX results corroborated high degradation of epoxy coating at marine site experiment as substantial increment in oxygen/carbon ratio and high concentration of Ti at coating surface due to ex-corporation of pigments were noticed. Worst performance of epoxy coating at marine test site as compared to salt spray testing may be due to the salt-laden winds of Karachi coastal city and corrosive constituents incorporated in atmospheres from industrial and automobiles exhaust. General diminution trend in gloss value, depletion of morphological features witnessed through SEM micrographs, curtailment of aryl ether and aromatic nuclei signals in FTIR spectrum, and emergence of new peaks in the 1620-1800 cm-1 region correspond to formation of new oxidation products; concluded that an insignificant protection offered by the epoxy coating due to its outdoor aging which led to ex-capsulation of pigments under moist conditions. Appraisal of these results have furnished an average coating performance correlation of 547.5 hpy (hours of salt spray test equivalence per year exposure test) at marine test site and 528 hpy at industrial test site in terms of blistering while equivalence mean in terms of rusting were found 680 hpy and 567 hpy at marine and industrial test sites respectively.
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