Browsing by Author "Getachew, Negash (PhD)"

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    Determination of Heavy Metals in the Soils of Flower Farms at Zeway, Sebeta and Holeta
    (Addis Ababa University, 2020-03-02) Gemechu, Yenenesh; Getachew, Negash (PhD)
    Soils polluted with heavy metals have become common across the globe due to increase in geologic and anthropogenic activities. Heavy metals in the soil refers to some significant heavy metals of biological toxicity, including mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), arsenic (As), etc. With the development of the economy, more specific with the development of industry the presence of heavy metals in the soil caused by this activity have gradually increased in recent years. These in turn have resulted in serious environment deterioration. The aim of this research was to evaluate the real situation of the soil contamination with heavy metals within the Flower farm of Zeway, Sebeta and Holeta in Ethiopia, and particularly in Oromia region. The obtained values of reagents volume, temperature and time for optimal procedure were 6 mL of the mixture of HCl and HNO3 with the ratio of 3:1, 210oC and 3:00 hour to mineralize powdered samples during wet digestion. The concentration of some selected metals in the soil samples were determined by micro wave plasma atomic emission spectroscopy. The mean concentration of heavy metals in soil samples near the flower farm exhibited decreased trend in the order of Fe > Zn >Ni > Cu > Cr .
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    Determination of Mercury in the Soils from Adolla (Shakiso) of Gold Mining Area, Ethiopia
    (Addis Ababa University, 2020-02-02) Tadele, Abebaw; Getachew, Negash (PhD)
    Mercury and its compounds are cumulative toxins and hazardous to human and animal health in the ecosystem. The toxicity of mercury in the soil depends on its oxidation states. So, the major effects of mercury poisoning manifest as neurological and renal disturbances as it can easily pass to the blood and damage the functions of brain, liver and kidney. Some of the common sources of mercury found in the environment are natural and anthropogenic sources. The concentration of mercury in soil samples used in the Adolla gold mining of Shakiso in Guji zone, Ethiopia was determined using Microwave plasma -atomic emission spectroscopy instrument. The result obtained revealed that the concentration of mercury is 0.111 mg/kg in the soil. So, the level of contamination of soils by mercury is high at present. As a result, the soil is polluted and toxic due to mercury.
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    Synthesis and Characterization of New Metal Complexes Derived From 1,4-Dihydroquinoxaline -2, 3- Dione, Orthophenylenediamine and Hydroquinone.
    (Addis Ababa University, 2018-04-05) Lemecha, Gemechu; Getachew, Negash (PhD)
    Metal complex of the type [MLCI2], M=Zn(II), L=tetra- dentate cyclic ligand, has been prepared through the condensation of orthophenylenediamine and 1,4-dihydroquinoxaline-2,3-dione in the presence of ZnCl2 (template system). The ligand coordinates through the four imine nitrogen atoms formed up on condensation of –NH2 function of orthophenylenediamine with C=O groups in 2-position of quinoxaline -2,3-dione. Another metal complex of zinc (II) was synthesized with 1,4-dihydroquinoxaline-2,3-dione and hydroquinone with behaving as mixed ligand system. These complexes have been characterized with the help of various spectral technique, such as 1H and 13CNMR, FT-IR, AAS elemental analysis and measurement of molar conductance in 1x 10-3 M solutions of DMSO. Furthermore, the determination of chloride test in metal content supports the concluded structures. The octahedral geometry was proposed for Zn-L complex and square planar for Zn (QXD) (HQ) complex.
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    Synthesis and Characterization of Ni(Ιι) and Cu(Ιι) Complexes of Quinoxaline-2,3-Dione and Hydroquinone
    (Addis Ababa University, 2018-04-01) Kebede, Geremew; Getachew, Negash (PhD)
    In this study the synthesis and characterization of two metal complexes of Ni(ΙΙ) and Cu(ΙΙ) are presented. New Hetrocyclic aromatic complexes of the type [ML2], where M is Ni(ΙΙ) or Cu(ΙΙ) and L is C8H6O2N2 were synthesis by the template method from quinoxaline-2,3-dione, hydroquinone with the corresponding hydrated metal salt of Ni(NO3)2.6H2O and CuCl2.2H2O. The complexes were distinctly colored and stable to atmospheric conditions. The synthesized complexes were characterized by UV, IR, 1HMR, AAS spectroscopic methods as well as by measurements of their respective molar conductance.The analysis result showed the formation of a square planar complexes of both metals with quinoxaline-2,3-dione.