Kinetic and Thermodynamic Studies of the Oxidation of Xylose in the Presence and Absence of Catalysts by Peroxdisuphate
Mawia Hassan Elsaim,
Jubrallah Elhaj,
Ibrahim Mukhtar
Issue:
Volume 4, Issue 1, June 2020
Pages:
1-6
Received:
5 August 2019
Accepted:
27 January 2020
Published:
6 July 2020
DOI:
10.11648/j.ajqcms.20200401.11
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Abstract: Sugars containing either aldehyde (aldose), ketone (ketose) or hemiacetal groups can be oxidized and are classified as reducing sugars. As oxidation of carbohydrates is widely studied under the field of organic chemistry, the present work deals with the study of the redox reactions between peroxodisulphate and xylose underuncatalyzed and catalyzed conditions. The kinetic study of the above reactions showed that these reactions followed first order with respect to peroxodisulphate and the silver nitrate ion catalyst and a fractional order of (0.2) with respect to xylose. Ag catalyst was used to increase the rate of reaction in case of xylose where reactions proceed very slowly with respect to time as compared to other sugars used. The oxidation showed that configuration of sugars has some bearing on rate of oxidation. At lower concentration of oxidants, the linear dependence of reaction rate tends towards new order at their higher concentration. The rate of reaction was affected at elevated temperature where thermodynamic activation parameters like activation energy (Ea), enthalpy change of activation (∆H#), free energy change of activation (∆G#) and entropy change of activation (∆S#) were determined by Arrhenius and Erying equations. The analysis of the reaction products using IR revealed the presence of formaldehyde and formic acid. A mechanism of the reactions was proposed to explain the experimentally observed rate law and the products.
Abstract: Sugars containing either aldehyde (aldose), ketone (ketose) or hemiacetal groups can be oxidized and are classified as reducing sugars. As oxidation of carbohydrates is widely studied under the field of organic chemistry, the present work deals with the study of the redox reactions between peroxodisulphate and xylose underuncatalyzed and catalyzed ...
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Distribution of Some Trace Metals in Bitter Leaf (Vernonia amygdalina) Obtained in Oil Exploration Area of Ibeno, Nigeria
Emmanuel Isaac Uwah,
Namnso Charles Udoaka,
Uduak Aniesua Essiett
Issue:
Volume 4, Issue 1, June 2020
Pages:
7-16
Received:
30 March 2020
Accepted:
3 May 2020
Published:
27 August 2020
DOI:
10.11648/j.ajqcms.20200401.12
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Abstract: Levels of some trace metals (Fe, Zn, Cu, Mn, Cr, Ni, Pb and Cd) in Vernonia amygdalina (bitter leaf) obtained in Ibeno, Akwa Ibom State, Nigeria were quantified using standard procedures. Soil samples as well as roots and leaves samples of the plant were collected from three locations (Okoroitak, Inua Eyet Ikot, Iwuo Okpom) in Ibeno, where intensive oil exploration activities are carried out. Samples were equally collected from Mbiabam Ibiono where there is no oil exploration, to serve as the controls. The results revealed that the metal levels in the soil ranged from < 0.06 mg/kg Cd to 8316.72±3.09 mg/kg Fe, those in the roots of the plant ranged from < 0.001 mg/kg Cd to 450.48±3.08 mg/kg Fe and those in the leaves, ranged from < 0.001mg/kg Cd to 1650.36±5.46 mg/kg Fe. The corresponding metal levels in the control samples were generally low compared to those of the study area. This could be attributed to the absence of oil exploration activities in the control area. Analysis of the metals pollution status of the plant using transfer factor (TF) revealed the trend: Cu > Pb > Zn >Cr > Mn > Ni > Cd > Fe. The levels of all the investigated metals in the analyzed V. amygdalina samples were lower than the WHO maximum permissible limits of the metals in plants and hence, the suitability of the analyzed V. amygdalina for human consumption in whatever form, at the time of the study.
Abstract: Levels of some trace metals (Fe, Zn, Cu, Mn, Cr, Ni, Pb and Cd) in Vernonia amygdalina (bitter leaf) obtained in Ibeno, Akwa Ibom State, Nigeria were quantified using standard procedures. Soil samples as well as roots and leaves samples of the plant were collected from three locations (Okoroitak, Inua Eyet Ikot, Iwuo Okpom) in Ibeno, where intensiv...
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