Browsing by Author "Ogunah, Joanne A."

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    Effects of Zeolite X on Dissipation of Hexazinone from Agricultural Waste Waters in Western Kenya
    (2013-10) Agoro, David J.; Kowenje, Chrispin O.; Lalah, Joseph O.; Osewe, Elly T.; Ogunah, Joanne A.
    Dissipation of hexazinone in Zeolite X treated wastewater followed pseudo first-order kinetics giving a calculated half-life of 41 days compared to a half-life of 144 days in untreated wastewater. The herbicide degraded faster (0.0067 h-1) in treated than in nonzeolite- treated wastewater (0.0027 h-1) forming products A, B, C, D and E within the first 12 h. Zeolite X effectively catalyzed the formation of product A compared to the rest. Calculated rate constants for formation of products A, B, D and E were: 8.33 x 10-4 h-1, 5.65 x 10-4 h-1, 5.52 x 10-4 h-1 and 1.38 x10-3 h-1 respectively in non-zeolite-treated wastewater; and 3.988 x 10-3 h-1, 4.875 x 10-4 h-1, 4.745 x 10-4 h-1 and 2.82 x 10-3 h-1 respectively in zeolite-treated wastewater
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    Effects of Zeolites X and Y on the Degradation of Malathion in Water
    (2013) Ogunah, Joanne A.; Kowenje, Chrispin O.; Osewe, Elly T.; Lalah, Joseph O.; Jaoko, David A.; Koigi, Robert N.
    The inclusion of both zeolites X and zeolite Y significantly affected the dissipation of malathion in water. In the fresh water, malathion degradation followed a pseudo-first order kinetics with concomitant half-life dropping from 8.76 hours in fresh water to 4.44 and 6.65 hours up on the introduction of faujasite X and Y, respectively. Zeolite X had higher degradation efficiency as compared to the Y type. In pure fresh water, Malathion mainly hydrolyzed to form malathion monocarboxylic and dicarboxylic acids as the only degradation products. However, in the presence of zeolites X and Y, in addition to the degradation products obtained in the fresh water, dimethyldithiophosphate was also formed. Notably, all the degradation products obtained are environmentally benign compared to the parent malathion. Eventually, both the adsorption on the zeolite framework and zeolite catalyzed degradation processes contributed to the overall dissipation behavior of the malathion and its degradation products
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    Staff Profile - Dr. Joanne Atieno Ogunah
    (University of Embu, 2015-07) Ogunah, Joanne A.
    Joanne holds a doctorate degree in chemistry from Maseno University. She has published two (2) papers in peer reviewed journals on enhanced degradation of xenobiotics in water using zeolites. She is a DAAD scholar and a visiting researcher at Forschungszentrum Jülich, Germany .