Study of atmospheric pollution levels by trace elements analysis of tree bark and leaves

The concentrations of Pb, Cu, Zn, Ni, Fe, and Mn in leaf and bark samples of 7 tree species at 22 sampling locations with different pollution levels, in Ogbomoso, Nigeria, were investigated. The metal concentrations (mean ± RSD in mg g-1) in leaf and bark samples, respectively, were: Pb, 203±70, 282±120; Cu, 19.5±4.2, 12.7±2.6; Zn, 42.7±12.9, 42.8±13.1; Ni, 30.0±11.1, 20.0±9.9; Fe, 869±348, 504±118; and Mn, 108±18, 73.7±13.8. The high-pollution automobile parking lots showed higher levels of these elements (p < 0.05). The correlation coefficient between element pairs of high and low-pollution automobile parking lots was carried out to determine the extent of relationship between the elements investigated. KEY WORDS: Atmospheric pollution, Trace elements analysis, Tree bark, Tree leaves  Bull. Chem. Soc. Ethiop. 2003, 17(1), 11-17

Removal of Basic Dye From Aqueous Solution By Adsorption On Melon Husk In Binary And Ternary Systems

The adsorption behaviour of a cationic dye (methylene blue)   in binary and ternary solutions on the husk of melon (Citrullus lanatus) seed was investigated in order to elucidate the effects of competitive adsorption on the kinetics and thermodynamics of the sorption process.  The experimental findings showed that adsorption equilibrium was reached within 120 min either in single, binary or ternary mixtures; and the   adsorption processes in all the systems studied were described by the pseudo-second order kinetics with the initial rate constant increasing as the  concentrations of the competing dyes were increased.  Five different equilibrium isotherm models ( Freundlich, Temkin, Langmuir, Harkin-Jura and Dubinin-Radushkevich) were applied and  Langmuir was the best-fitting one for the adsorption of methylene blue dye in single system (R2 &gt; 0.99), while the binary and ternary systems were best described by Freundlich model (R2 &gt; 0.99). The sorption processes were thermodynamically feasible as ?G values were negative. Adsorption in both single and binary systems was exothermic while that of ternary system was endothermic. Keywords: melon husk, binary dye system, ternary dye system, methylene blue,                       Competitive adsorption, isotherms, thermodynamics, basic dy

Aliphatic and polycyclic aromatic hydrocarbons profiles of photomodified natural bitumen of Agbabu, Southwestern Nigeria

The impact of sunlight on aliphatic and polycyclic aromatic hydrocarbons profiles of Agbabu natural bitumen in Nigeria was investigated. The raw flow type of the bitumen was purified and exposed to sunlight for six consecutive months. Different portions of the bitumen were withdrawn at an interval of one month and were separated into aliphatic and polycyclic aromatic hydrocarbon fractions by column chromatography, followed by the GC analyses of various fractions. The total aliphatic hydrocarbon content was found to be 485, 424, 416 and 392 g/kg for control, one, three and six months solar-irradiated bitumen samples, respectively; while the total polycyclic aromatic hydrocarbons content found in the control, one, three and six months solar-irradiated bitumen samples were 708, 733, 609 and 638 µg/g, respectively. The effects of sunlight on the compositional patterns of bitumen were discussed. KEY WORDS: Agbabu, Bitumen, Sunlight, GC, Aliphatic hydrocarbon, Polycyclic aromatic hydrocarbon  Bull. Chem. Soc. Ethiop. 2010, 24(3), 461-466

Synthesis and fungicidal activity of acetyl substituted benzyl disulfides

The synthesis and fungicidal activity of acetyl substituted benzyl disulfides 1(a – g) are reported. The compounds were characterized by elemental analysis, nuclear magnetic resonance (1H NMR and 13C NMR) and mass spectrometric techniques. The results of the biological screening showed that the synthesized compound possess very high fungicidal activity. KEY WORDS: Acetyl substituted benzyl disulfides, Fungicidal activity  Bull. Chem. Soc. Ethiop. 2003, 17(1), 53-60

<b>Study of atmospheric pollution levels by trace elements analysis of tree bark and leaves</b>

The concentrations of Pb, Cu, Zn, Ni, Fe, and Mn in leaf and bark samples of 7 tree species at 22 sampling locations with different pollution levels, in Ogbomoso, Nigeria, were investigated. The metal concentrations (mean  RSD in g g-1) in leaf and bark samples, respectively, were: Pb, 20370, 282120; Cu, 19.54.2, 12.72.6; Zn, 42.712.9, 42.813.1; Ni, 30.011.1, 20.09.9; Fe, 869348, 504118; and Mn, 10818, 73.713.8. The high-pollution automobile parking lots showed higher levels of these elements (p < 0.05). The correlation coefficient between element pairs of high and low-pollution automobile parking lots was carried out to determine the extent of relationship between the elements investigated

Kinetics of periodate oxidation of tris-(4,4'-dimethyl-2,2'-bipyridine) iron(II) in acid medium

The kinetics and mechanism of periodate oxidation of the complex tris-(4,4'-dimethyl-2,2'-bipyridine) iron(II) in acid medium was investigated. The complex undergoes extensive protonation in acid medium. Both protonated and the unprotonated species undergo electron transfer reaction with the active periodate species such as IO3+ and H6IO6+. The protonated species forms an ion pair with IO3- and thus suggests an outer-sphere mechanism for the reaction. (Received March 22, 2000; revised October 25, 2000)Bull. Chem. Soc. Ethiop. 2000, 14(2), 175-184Bulletin of the Chemical Society of Ethiopia. ISSN: 1011-392

A study of the water quality of the osun river: metal monitoring and geochemistry

The concentrations and distributions of Cd, Cu, Ni, Pb, Cr and Zn in Osun river, selected rivers in the region and groundwaters have been studied, in order to establish the current levels of pollution. The metal concentration (mean plus or minus RSD in g dm-3) in the Osun river for the sampling periods of May, June and August, respectively, were: Cd, 1.45 plus or minus 0.65, 1.40 plus or minus 0.37, 1.25 plus or minus 0.52; Ni, 21.8 plus or minus 6.22, 10.6 plus or minus 3.68, 15.3 plus or minus 6.01; Pb, 7.16 plus or minus 3.30, 8.45 plus or minus 3.24, 4.86 plus or minus 1.98; Cu, 16.7 plus or minus 9.32, 11.9 plus or minus 4.81, 8.27 plus or minus 3.80; Cr, 250 plus or minus 118, 400 plus or minus 160, 150 plus or minus 72.9; Zn, 398 plus or minus 109, 289 plus or minus 113, 259 plus or minus 94.4. The correlation coefficient between metal pairs of river water and groundwater samples are calculated and possible sources of the polluting substances are discussed

Synthesis and fungicidal activity of substituted dibenzyl trisulfides

Articl

Determination of moisture-dependent physical and thermal properties of jack bean (Canavalia ensiformis) related to design of processing machines

The study was carried out to investigate the effect of the moisture content on physical properties; axial dimension, seed volume, surface area, arithmetic and geometric mean diameter, aspect ratio, sphericity, true and bulk density, angle of repose and static coefficient of friction, and thermal properties; specific heat capacity, thermal conductivity and thermal diffusivity of Jack beans seeds. The properties were evaluated at six levels of moisture ranged from 10.12% to 30.51% d.b. The physical properties are: major, minor and intermediate diameter (19.42 to 20.78mm, 13.92 to 14.59 mm and 13.92 to 14.59 mm), surface area (152.2 to 167.2mm2), seed volume (446.9 to 595.2mm3), arithmetic mean (14.42 to 15.72mm), geometric mean (13.53 to 14.87mm), sphericity (0.696 to 0.716), aspect ratio (0.72 to 0.70), bulk density (0.677 to 0.376 kg/m3), true density ( 0.55 to 0.94 kg/m3), angle of repose (30.63° to 37.18°), static coefficient of friction for each surface (0.417 to 0.625, 0.438 to 0.692 and 0.357 to 0.459) for aluminium, plywood and glass, respectively. The thermal properties are: thermal conductivity (1.5350 to 4.9295 W/mK), thermal diffusivity (2.82 × 10-5 to 5.63 × 10-5 m2/s), and specific heat (1.3747 to 1.8912 kJ/kgK). The experimental data were satisfactorily fitted as functions of the moisture content using empirical models. Within the range of moisture levels considered, moisture content exhibits a significant great influence on the studied properties.Keywords: Axial dimensions, Jack bean, moisture content, physical properties, thermal propertie