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Okoduwa S.I.R.,Nigerian Institute of Leather and Science and Technology NILEST | Mbora L.O.,Dir Of Science Laboratory Technology | Adu M.E.,Antiretroviral Therapy Center | Adeyi A.A.,Nigerian Institute of Leather and Science and Technology NILEST
Biochemistry Research International | Year: 2015

The need to develop effective alternative for synthetic indicators is the demand of present-day chemistry. The acid-base indicator properties of Rose (Rosa setigera), Allamanda (Allamanda cathartica), and Hibiscus (Hibiscus rosa-sinensis) flowers were examined. Colour pigments were extracted from the flowers via cold and solvent extraction using soxhlet extractor. The pH value of the extracts with wavelengths of absorption was determined using ultraviolet spectrophotometer. From the results obtained, all the extracts exhibited sharp contrast between their colours in acid and base. Their pH was found to be 5.5 for cold extract of Rose and 5.6 for solvent extraction, 5.24 for cold extract of a Hibiscus and 6.52 for solvent extraction, 5.35 for cold extract of Allamanda, and 5.45 for solvent extraction. The maximum wavelengths of absorption obtained for all the extract fall within the visible region of electromagnetic spectrum. These values are almost similar to that obtained from synthetic indicators. It is on these bases that we concluded that natural indicators could be an excellent replacement for synthetic indicators since they are cheap, readily available, simple to extract, not toxic, user and environmentally friendly. © 2015 Stanley I. R. Okoduwa et al. Source

Putshaka J.D.,Nigerian Institute of Leather and Science and Technology NILEST | Adamu K.I.,Nigerian Institute of Leather and Science and Technology NILEST | Jauro A.,University of Nigeria | Tanko S.F.,Nigerian Institute of Leather and Science and Technology NILEST
Journal of Testing and Evaluation | Year: 2013

Tannery solid waste in the form of buffing dust and conventional feedstock such as sawdust were used to produce adsorbents (activated carbon) under the same experimental conditions. The adsorbent from both feedstocks were produced after carbonization at temperatures of 500°C-800°C and characterized. Adsorption performance of the activated carbon samples produced was comparatively studied using methylene blue as adsorbate. Results reveal that activated carbon obtained from sawdust after carbonization at 800°C exhibited better adsorption properties than its counterpart produced at the same temperature. Conversely, activated carbon produced from tannery buffing dust after carbonization at 500°C displayed superior adsorption capacity than that obtained from sawdust at the same temperature. The effect of carbon dosage and time on adsorption by both carbon samples was also determined. The Freundlich and Langmuir adsorption isotherm model used in this study reveals that, although the Freundlich isotherm had a better fit (R2=0.980) for tannery buffing dust than sawdust (R2=0.943), Langmuir isotherm exhibited the best overall fit R2=0.9893 and R2=0.9896 for sawdust and tannery buffing dust, respectively. The low temperature used in production and the good adsorption performance of activated carbon obtained from tannery buffing waste in this study makes it a more cost effective adsorbent to produce than activated carbon produced from sawdust. © ASTM Int'l (all rights reserved). Source

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