Adsorption of Cu2+ and Cr6+ in Aqueous Solution by a Thermally Modified Biosorbent Based on Cotton Cakes
Abia Daouda,
Yowe Kidwe,
Domga Richard,
Domga,
Harouna Massai
Issue:
Volume 8, Issue 4, December 2019
Pages:
66-74
Received:
27 September 2019
Accepted:
28 October 2019
Published:
19 November 2019
Abstract: This work focuses on the retention capacity of Cu2+ and Cr6+ ions in water by adsorption on a thermally modified biosorbent based on cotton cakes. The solutions treated are synthetic copper nitrate solutions rich in Cu2+ ions and potassium dichromate rich in Cr6+ ions in distilled water. The adsorption tests were carried out by mixing, with stirring (250 rpm), 0.02 g of the adsorbent for the solution containing the Cu2+ ions and 0.04 g for that containing the Cr6+ ions with a volume of 50 mL of these solutions. Kinetic studies have shown that the maximum adsorption is obtained after 20 minutes. In addition, the pH of the medium influences the adsorption process and the yield is improved with increasing pH. Amounts of copper and chromium adsorbed increase with increasing initial concentrations of these ions up to 40 mg/L. Similarly, adsorbed amounts increase with increasing mass of the adsorbent. On the other hand, these adsorbed quantities decrease with increasing temperature. The best adopted kinetic models are pseudo-second-order, Intraparticular and Evlovich. The adsorption isotherms conform to the Langmuir and Dubinin-Redushkovic models. The values of thermodynamic parameters such as free enthalpy (ΔH° KJ/K.mol), entropy (ΔS° KJ/K.mol) and isosteric adsorption heat (ΔG° KJ/K. mol) at temperatures of 293; 303; 313 and 323K, all negative, show that we have to do with an exothermic adsorption, physical, ordered and spontaneous. The electrostatic attraction between the Cu2+ and Cr6+ ions and the adsorbent for the pH values above the pH of the point of zero charges shows that we have to do with a chemical adsorption.
Abstract: This work focuses on the retention capacity of Cu2+ and Cr6+ ions in water by adsorption on a thermally modified biosorbent based on cotton cakes. The solutions treated are synthetic copper nitrate solutions rich in Cu2+ ions and potassium dichromate rich in Cr6+ ions in distilled water. The adsorption tests were carried out by mixing, with stirrin...
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Nutritional Potential of Co-products of Two Species of Benin Cucurbits
Yete Pélagie,
Togbe Alexis,
Yovo Franck,
Wotto Valentin,
Sohounhloue Dominique
Issue:
Volume 8, Issue 4, December 2019
Pages:
75-81
Received:
6 November 2019
Accepted:
27 November 2019
Published:
9 December 2019
Abstract: In the perspective of sustainable development, which involves the use of all biomass, two oilseeds have been selected according to their potential interests: Citrullus lanatus and Lagenaria siceraria. The physico-chemical characterization (oil and extraction cake) has been done. Thus, for extracted oils, unsaturated fatty acids are in the majority with the predominance of oleic and linoleic acids (21.31 to 44.36% and 16.20 to 70.35% respectively). The study of unsaponifiable fractions revealed that: Citrullus lanatus oil contains 134 mg/100g sterols (including 78.60% β-sitosterol) and 83.9mg/100g tocopherols (including 73.7% α-tocopherol) and Lagenaria siceraria oil contains 124mg/100 sterols (including 58.14% β-sitosterol) and 76.4mg/100g tocopherols (including 66.9% α-tocopherol). Phospholipids (0.39 and 0.40% respectively for Lagenaria siceraria and Citrullus lanatus) were quantified on the basis of phosphorus content. This study shows the nutritional value of oils through their compositions in essential fatty acids, their richness in phytosterols and tocopherols on the one hand and the ways in which co-products resulting from the extraction of selected seeds on the other hand are valued. Research showing the influence of stabilizing agents on the quality and stability of oils should be carried out to make their use easier. Tests of the use of these oils in the fields of cosmetics, pharmaceuticals, paints and polymer synthesis industries could be carried out.
Abstract: In the perspective of sustainable development, which involves the use of all biomass, two oilseeds have been selected according to their potential interests: Citrullus lanatus and Lagenaria siceraria. The physico-chemical characterization (oil and extraction cake) has been done. Thus, for extracted oils, unsaturated fatty acids are in the majority ...
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