Chemical Science International Journal

In this paper a new series of 1,3,4-thiadiazole derivatives have been designed, synthesized and evaluated as antimicrobial agents. New compounds were prepared by the reaction of 5-amino-1,3,4-thiadiazole-2(3H)-thione with appropriate aldehydes. The structures of the obtained compounds were confirmed by means of ¹H NMR and ¹³C NMR. All synthesized compounds were tested for their in vitro antibacterial and antifungal activities using the broth microdilution method. Our results showed that the three of synthesized compounds had bactericidal or fungicidal effect against reference strains of Gram-positive bacteria, mainly opportunistic S. epidermidis, M. luteus, Bacillus spp., and yeast belonging to Candida spp.

The present work consists on an experimental characterization of non-purified clay material. The survey is focused on the chemical, physical, and mechanical properties variation during the convective drying of the material. Clay identification by atomic absorption spectrophotometer and X-ray diffractometer are used to determine the exact composition. The study covers also some essential physical properties of the material such as density, volume shrinkage, and porosity in one hand, and some mechanical properties: Young modulus and the parameters of viscoelastic behavior for the other hand. The novelty is the variation of the properties function of the material moisture content. The clay was identified kaolinite as major fraction. The true density is evaluated to (2685 +/- 35 kg/m³). And Young modulus is about (15 MPa) for dried material. The results are judged to be acceptable comparing to the literature data.

Coordination polymers derived from 1,2,4,5-benzenetetracarboxylate (H₂btec^2- or btec^4- ), Fe(II), Mn(II), Co(II), Ni(II), Cu(II), Cd(II) or UO₂(II) metal ions, 1,10-phenanthroline(1,10-phen) or 2,2^'-bipyridine(2,2^'-bipy)  were prepared. The polymers were characterized by elemental analysis, IR and electronic spectra, electrical conductance, magnetic susceptibility measurements and thermal behavior. The electronic spectra, magnetic susceptibility measurements and X-ray structure determination revealed octahedral and tetrahedral geometries around the metal ions. Kinetic and thermodynamic parameters of the thermal decomposition were computed from the thermal data using the Coats-Redfern equation. From the X-ray powder diffraction the particle sizes (6.4-25.4 nm) of the coordination polymers could be calculated using the Scherrer^`s equation.

Six common Nigerian weeds namely Helianthus annus, (Sunflower), Imperala cylindrical (Sword grass), Sida acuta burn (Broom weed), Gossypium spp (Cotton), Eleusine indica (Goose grass) and Chromoleaeceae Odarata (Siam weed) grown around Enyigba lead mines were investigated within a period of two years (2008-2010) for their abilities to remove heavy metals from the soils of the derelict mines. X-ray Fluorescence (XRF) spectrometric method was used to determine the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the top and sub soils and also in the roots, stems and leaves of the studied plants. The Pollution Indices (PI) of the soil was evaluated as well as the Bioaccumulation Factors (BAF) and Translocation Factors (TF) of the weeds and they were used to determine the phytoremediation potentials of the weeds. The results obtained revealed the mean concentrations (mg/Kg) of metals in the studied plants were of the range: Pb (12.62 – 417.2); As (0.38 – 2.26); Cd (8.46 – 144.6); Cu (32.81 – 420.40); Cr (30.2 – 184.2); Zn (0.26 – 16.87); Mn (12.94 – 155.80) and Ni (3.86 – 47.42). Levels of heavy metals in Chromoleaeceae odorata and Imperata Cylindrical were significantly higher than in the other weeds. Higher accumulation of metals was observed in roots than in the stems and the leaves. High BAF and TF (<1) observed in some of the studied plants suggest that they could be employed as efficient phytoremediation agents in cleaning up polluted soil. Statistical analysis of variance (ANOVA) at P<0.05 showed variations in the heavy metal levels between and within groups while Fisher’s Least Significant Difference (LSD) Correlation analysis identified a strong relationship between the investigated plant and soil samples. Pollution Indices of metals in the studied soil sample in addition to the Bioaccumulation Factors and Translocation Factors of the studied weeds are important parameters to evaluate plants phytoremediation potentials.

Five authentic Acacia polyacantha whole gum samples were collected as natural exudates and five acetone fractions were obtained. Analysis of the whole gum samples and the fractions were carried out t for nitrogen (protein), specific rotation, intrinsic viscosity, pH, equivalent weight, uronic acid content, refractive index and average molecular weight. Results of refractive index for the whole samples and the fractions were found to share the same value (1.3337). Significant differences were obtained between the values of these parameters for the whole gum samples as well as the fractions and it is also among the fractions themselves.

In particular fractions 1,2,3,4and 5 showed nitrogen content of 0.32%, 0.35%, 0.40%, 0.39%and0.37% and protein content of (2.11%,2.31%,2.64%, 2.57% and2.44%) respectively. The mean values of specific optical rotation of the fractions was found-13.5 0, -14.50, -15.0 0,-16.00 and -14.50 respectively. The average molecular weight of the fractions gave 2.669x105, 2.669X105, 2.714X105, 2.339X105 and 2.754X105 respectively. The statistical analysis showed significant differences (P ≤ 0.05) for some parameters such as, intrinsic viscosity, pH and the average molecular weight. These data confirms the heterogeneity of Acacia polyacantha gum, and their fractions.

Aims: The present study assessed the quality of rainwater in Ayanfuri in the Upper Denkyira West District, Central Region of Ghana.

Study Design: Triplicate samples were collected from three sampling points.

Place and Duration of Study: Triplicate rainwater samples were collected within the two months (February and March, 2014) in Township.

Methodology: Physico-chemical and trace metal analyses of the samples were carried out at the Council for Scientific and Industrial Research - Water Research Institute Laboratory, Tamale using standard methods. 

Results: The physico-chemical values recorded were within World Health Organization limits for potability except pH and turbidity. The mean concentrations of the trace metals that include total iron (0.51 mg/l), lead (0.28 mg/l) and cadmium (0.12 mg/l) in the rainwater samples exceeded WHO permissible limits for potability except manganese (0.28 mg/l).

Conclusion: The study shows that rainwater may not be suitable for drinking and other domestic purposes unless it is treated. The compromised rainwater quality could be influenced by anthropogenic activities such as mining that has increased the concentration of pollutants in the atmosphere. The quality of rainwater can be improved if monitoring authorities step-up their activities.