Browsing by Author "Chiririwa, Haleden"

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    Adsorption of Mercury by Pterocarpus Anglolensis: Study on Adsorption Isotherms and Kinetics
    (Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR, 2022) Mapombere, Garainesu; Nyoni, Bothwell; Sibali, Linda L.; Chiririwa, Haleden; Seodigeng, Tumisang
    The efficiency of Pterocarpus Anglolensis sawdust, an abundantly available waste product of the timber industry, capacity as an adsorbent for mercury was investigated. A series of batch experiments was carried out with experimental conditions of metal concentration, adsorbent concentration, pH, and contact time being changed. The concentration of the metal ion was deduced using spectrophotometric means. The adsorption efficiency was found to be pH-dependent with pH 4 being the optimum. 90 minutes was found to be the equilibrium time with particle size range 90-124 μm being the most efficient. Maximum adsorption of mercury was evaluated at 80.33 %. The experimental data was best modeled by the Freundlich isotherm and Pseudo second-order kinetic models. The calculated adsorption parameters are Kf = 0.0002 L/mg, bF = 3.0 and k2 = 0.00016 g/μg.min.
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    Determination of the Most Effective Concentration of Deet and Permethrin in A Mosquito Repellent Soap and Assay of the Active Ingredients
    (Research India Publications, 2016) Mtisi, Farlane; Parekh, Champaklal T.; Ochieng, Aoyi; Chiririwa, Haleden
    The study was carried out to investigate the most effective concentration of DEET and Permethrin in a mosquito repellent soap and to develop a method for the assaying of the active ingredients. The effect of perfume in a repellent soap was also investigated. In the study nine soaps were prepared and the concentrations of DEET and Permethrin were varied with six soaps having both ingredients. Efficacy tests were carried out on the different soaps. The most effective and economic soap in repelling mosquitoes was the one which had 50 % DEET. Physical and chemical tests revealed that the soaps had an average total fatty matter of 71.6 %, average moisture content of 14.35 % and average free alkali of 0.04.
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    New routes to the preparation of [ru3(co)12], [h4ru4(co)12], [rucl2(pph3)3] and [rucl2(cod)]n from anglo platinum refinery
    (Zimbabwe Journal of Science and Technology, 2013) Chiririwa, Haleden; Moss, John R.
    New and improved routes for the preparation of ruthenium complexes are described. [Ru3(CO)12], [H4Ru4(CO)12], [RuCl2(PPh3)3] and [RuCl2(COD)]n have been prepared from [(NH4)2RuCl6] and [H2RuCl6]. Traditionally these ruthenium complexes have been prepared from commercially available RuCl3.3H2O, but here we describe their preparation from refinery materials.