Synergistic and Antagonistic Effects of Sodium Molybdate-Zn2+System

The inhibition efficiency (IE) of sodium molybdate (SM) in controlling corrosion of carbon steel in an aqueous solution containing 120 ppm of Cl-, in the absence and presence of Zn2+has been evaluated by weight-loss method. A synergistic effect exists between SM and Zn2+when the concentration of Zn2+is 25 ppm and above. Inhibition efficiencies obtained are greater than 85%. Antagonistic effect exists between SM and Zn2+when the concentration of Zn2+is 10 ppm and below. The SM-Zn2+system shows excellent IE up to third day. Above third day IE decreases. Acceleration of corrosion takes place. Excellent IE is shown at pH 5,7 and 12. At pH 9, IE decreases since Zn2+is precipitated as Zn(OH)2in the bulk of the solution. Polarization study reveals that SM-Zn2+system functions as a mixed inhibitor. FTIR spectra reveal that the protective film consists of Fe2+-SM complex and Zn(OH)2.

Determination of Glycol Ethers in Ambient Air by Adsorption Sampling and Thermal Desorption with GC/MS Analysis: Performance Evaluation and Field Application

Some of glycol ethers, such as 2-methoxyethanol (2-ME) and 2-ethoxyethanol (2-EE) are known to be toxic and classified as hazardous air pollutants in USA, Japan and Germany. In Korea, however, there has been no study conducted so far for these compounds in ambient air. In addition, no clear methodologies for the measurement of glycol ethers have been yet established. We carried out this study to evaluate a sampling and analytical method for the determination of glycol ethers, in ambient air samples collected in specific industrial areas of South Korea. To measure glycol ethers, adsorption sampling and thermal desorption with GC/MS analysis were used in this study. The analytical method showed good repeatability, linearity and sensitivity. The lower detection limits were estimated to be approximately 0.3∼0.5 ppb. Based on storage tests, it was suggested that samples should be analyzed within two weeks. It was also demonstrated that this method can be used for the simultaneous measurement of glycol ethers and other aromatic VOCs such as benzene, toluene, and xylenes. Field sampling campaign was carried out at 2 sites, located in a large industrial area, from October 2006 to June 2007, and a total of 480 samples were collected seasonally. Among them, 2-ME was not detected from any samples, while 2-EE and 2-Ethyloxyethylacetate (2-EEA) were found in 7 and 70 samples, respectively. The measured concentrations of 2-EE and 2-EEA for samples were ranged from 0.7-2.5 ppb and from 0.5-10.5 ppb, respectively. To our knowledge, this is the first measurement report for glycol ethers in the ambient atmosphere not only in Korea but also the rest of the world.

A Facile Synthesis and Studies of Some New Chalcones and Their Derivatives Based on Heterocyclic Ring

Chalcones(6a-f)have been prepared by the condensation of ketone(5)and different aromatic and heterocyclic aldehydes. These chalcones(6a-f)on treatment with guanidine hydrochloride and phenyl hydrazine hydrochloride in presence of alkali give aminopyrimidines(7a-f)and phenylpyrazolines(8a-f)respectively. All the newly synthesized compounds have been characterized on the basis of IR,1HNMR spectral data as well as physical data. Antibacterial activity (minimum inhibitory concentration MIC) against Gram-positiveS. aureusMTCC 96 andS. pyogeneusMTCC 442 and Gram-negativeP. aeruginosaMTCC 1688 andE. coliMTCC 443 bacteria, as well as antifungal acivities (MIC) againstC. albicansMTCC 227,A. nigerMTCC 282 andA. clavatusMTCC 1323 were determined by broth dilution method.

Eggshell Powder as an Adsorbent for Removal of Fluoride from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies

A new medium, eggshell powder has been developed for fluoride removal from aqueous solution. Fluoride adsorption was studied in a batch system where adsorption was found to be pH dependent with maximum removal efficiency at 6.0. The experimental data was more satisfactorily fitted with Langmuir isotherm model. The kinetics and the factor controlling adsorption process fully accepted by pseudo-second-order model were also discussed. Eawas found to be 45.98 kJmol-1by using Arrhenius equation, indicating chemisorption nature of fluoride onto eggshell powder. Thermodynamic study showed spontaneous nature and feasibility of the adsorption process with negative enthalpy (∆H0) value also supported the exothermic nature. Batch experiments were performed to study the applicability of the adsorbent by using fluoride contaminated water collected from affected areas. These results indicate that eggshell powder can be used as an effective, low-cost adsorbent to remove fluoride from aqueous solution as well as groundwater.

Unsymmetrical Schiff Base Functionalized as Monobasic Tridentate Ligand on Complexation with Some Transition Metal Ions

Cu(II), Co(II), Ni(II) and Mn(II) complexes of Schiff base derived from 2-aminophenol and pyrrole-2- carbaldehyde have been prepared. The complexes are formed by coordination of N and O atoms of the ligand. Their structures were characterized by physico-chemical and spectroscopic methods. Molecular structure of the complexes has been optimized by MM2 calculations and suggests a tetrahedral/ square planar geometry. The bio-efficacy of the ligand and their complexes has been examined against the growth of bacteriain vitroto evaluate their anti-microbial potential.

Characterization of Fly Ash Generated from Matla Power Station in Mpumalanga, South Africa

In this study, fly ash was obtained from Matla power station and the physicochemical properties investigated. The fly ash was characterized by x-ray fluorescence, x-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectrometry. Surface area, particle size, ash and carbon contents, pH, and point of zero charge were also measured. The results showed that the fly ash is alkaline and consists mainly of mullite (Al6Si2O13) and quartz (SiO2). Highly toxic metals As, Sb, Cd, Cr, and Pb as well as metals that are essential to health in trace amounts were also present. The storage and disposal of coal fly ash can thus lead to the release of leached metals into soils, surface and ground waters, find way into the ecological systems and then cause harmful effect to man and its environments.

Electrochemical Behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones

The electrochemical behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones has been investigated at dme and gc electrodes in buffer solutions of pH 2.0, 4.0, 6.0, 8.0 and 10.0 using dc polarography and cyclic voltammetry and coulometry. The compounds exhibit one well defined wave in the entire pH range of study. The process is irreversible and diffusion controlled. Controlled potential electrolysis indicates the involvement of four electrons in the reduction process. The effect of solvent, cations and anions, temperature and substitutents on the mechanism of reduction has been studied. Based on the results obtained the mechanism of reduction has been suggested.

Alkali Activation of Oil Shale Ash Based Ceramics

Timahdit oil shale was subjected to firing transformation via ceramics processing followed by alkali activation to synthesis a materials combining the mechanical properties of ceramics and Zeolites. The mineralogical transformations during firing oil shale have been studied. The main crystalline phases found in oil shale ash (OSA) were wollastonite, gehlenite and augite. Modified oil shale ash (MOSA) was obtained with HNO3acid-leaching in the aim to diminish Ca content. Our experimental approach required a NaOH alkaline activating solution with different concentrations (0.5; 1; 2; 4; 6 and 8M). In our study, X-ray diffraction (XDR), Fourier transform infrared (FTIR) and SEM/EDS analysis were used to evaluate the effect of alkali activation on the structural arrangement of the starting materials (OSA and MOSA) in our study. The quantity and the type of the produced zeolites depended critically on the starting materials and on the NaOH concentration.

Polymer Composite—A Potential Biomaterial for the Removal of Reactive Dye

Poly Pyrrle saw dust composite was prepared by reinforcement of natural wood saw dust (obtained fromEuphorbia Tirucalli Lwood) and Poly Pyrrole matrix phase. The present study investigates the adsorption behaviour of Poly Pyrrole Saw dust Composite towards reactive dye. The batch adsorption studies were carried out by varying solution pH, initial dye concentration, contact time and temperature. The kinetic study showed that adsorption of Reactive Red by PPC was best represented by pseudo-second order kinetics with ion exchange adsorption. The equilibrium data were analyzed by Freundlich and Langmuir isotherm model. The equilibrium isotherm data were fitted well with Langmuir isotherm model. The maximum monolayer adsorption capacities calculated by Langmuir model were 204.08 mg/g for Reactive Red at 303 K. The thermodynamic parameters suggest the spontaneous, endothermic nature of ion exchange adsorption with weak Vader walls force of attraction. Activation energy for the adsorption of Reactive by Poly Pyrrole Composite was 11.6387 kJ/mole, Isosteric Heat of adsorption was 48.5454 kJ/mole also supported the ion exchange adsorption process in which forces of attraction between dye molecules and PPC is weak.

Synthesis, Isolation and Characterization of Process-Related Impurities in Oseltamivir Phosphate

Three known impurities in oseltamivir phosphate bulk drug at level 0.1% (ranging from 0.05-0.1%) were detected by gradient reverse phase high performance liquid chromatography. These impurities were preliminarily identified by the mass number of the impurities. Different experiments were conducted and finally the known impurities were synthesized and characterized.