<b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b>
This paper reports results on complex formation reactions between OH<sup>-</sup>, Cl<sup>-</sup>, EDTA and carbohydrate ligands with Pb<sup>2+</sup> ions at various [L<sub>T</sub>]:[M<sub>T</sub>] ratios and at different pH values (1.5-13.0...
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| Format: | Article |
| Language: | English |
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Chemical Society of Ethiopia
2005-06-01
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| Series: | Bulletin of the Chemical Society of Ethiopia |
| Subjects: | |
| Online Access: | http://www.ajol.info/index.php/bcse/article/view/21117 |
| _version_ | 1818208128110428160 |
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| author | J. Catherine Ngila Ned Silavwe Jackson K. Kiptoo Jonathan E.R. Thabano |
| author_facet | J. Catherine Ngila Ned Silavwe Jackson K. Kiptoo Jonathan E.R. Thabano |
| author_sort | J. Catherine Ngila |
| collection | DOAJ |
| description | This paper reports results on complex formation reactions between OH<sup>-</sup>, Cl<sup>-</sup>, EDTA and carbohydrate ligands with Pb<sup>2+</sup> ions at various [L<sub>T</sub>]:[M<sub>T</sub>] ratios and at different pH values (1.5-13.0). Differential pulse anodic stripping voltammetry (DPASV) employing an <i>ex situ</i> plated thin mercury film electrode (TMFE) was used to measure the shifts in peak potentials. Formation of simple, polyligand as well as mixed ligand complexes are reported. The reactions between the Pb(II) and the carbohydrate ligands showed pronounced pH dependency on metal forms compared to reactions with simple inorganic ions such as chloride. Modeling of the experimental data obtained with the DPASV method was done using computer software (3D-VISE). The calculated complex formation curves (CCFC) based on mass balance equations were fitted to the experimental complex formation curves (ECFC) and the goodness of the fit evaluated (RSD < 5%). These studies were applied to Pb, Cr, Zn, Cd and Cu speciation in brewery wastewater in which differences between total metal determined by flame atomic absorption spectrometry (FAAS) after acid digestion and labile fraction determined by DPASV were used to estimate the percentage of non-labile fraction (mainly metal-organic complexes). Up to 90% of the metal was found to exist as the “inert” fraction, implying that the effluent system from the brewery industry poses minimal health risks to the environment with regard to toxic forms of the metals as the organically bound metal forms are generally known to have low toxicity compared to the aquo or labile metal forms. |
| first_indexed | 2024-12-12T04:39:53Z |
| format | Article |
| id | doaj.art-c594462d7dfa48139a95a41bb99aa95d |
| institution | Directory Open Access Journal |
| issn | 1011-3924 1726-801X |
| language | English |
| last_indexed | 2024-12-12T04:39:53Z |
| publishDate | 2005-06-01 |
| publisher | Chemical Society of Ethiopia |
| record_format | Article |
| series | Bulletin of the Chemical Society of Ethiopia |
| spelling | doaj.art-c594462d7dfa48139a95a41bb99aa95d2022-12-22T00:37:51ZengChemical Society of EthiopiaBulletin of the Chemical Society of Ethiopia1011-39241726-801X2005-06-01191125138<b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b>J. Catherine NgilaNed SilavweJackson K. KiptooJonathan E.R. ThabanoThis paper reports results on complex formation reactions between OH<sup>-</sup>, Cl<sup>-</sup>, EDTA and carbohydrate ligands with Pb<sup>2+</sup> ions at various [L<sub>T</sub>]:[M<sub>T</sub>] ratios and at different pH values (1.5-13.0). Differential pulse anodic stripping voltammetry (DPASV) employing an <i>ex situ</i> plated thin mercury film electrode (TMFE) was used to measure the shifts in peak potentials. Formation of simple, polyligand as well as mixed ligand complexes are reported. The reactions between the Pb(II) and the carbohydrate ligands showed pronounced pH dependency on metal forms compared to reactions with simple inorganic ions such as chloride. Modeling of the experimental data obtained with the DPASV method was done using computer software (3D-VISE). The calculated complex formation curves (CCFC) based on mass balance equations were fitted to the experimental complex formation curves (ECFC) and the goodness of the fit evaluated (RSD < 5%). These studies were applied to Pb, Cr, Zn, Cd and Cu speciation in brewery wastewater in which differences between total metal determined by flame atomic absorption spectrometry (FAAS) after acid digestion and labile fraction determined by DPASV were used to estimate the percentage of non-labile fraction (mainly metal-organic complexes). Up to 90% of the metal was found to exist as the “inert” fraction, implying that the effluent system from the brewery industry poses minimal health risks to the environment with regard to toxic forms of the metals as the organically bound metal forms are generally known to have low toxicity compared to the aquo or labile metal forms.http://www.ajol.info/index.php/bcse/article/view/21117Metal speciationCarbohydratesBrewery wastewaterDifferential pulse voltammetry |
| spellingShingle | J. Catherine Ngila Ned Silavwe Jackson K. Kiptoo Jonathan E.R. Thabano <b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b> Bulletin of the Chemical Society of Ethiopia Metal speciation Carbohydrates Brewery wastewater Differential pulse voltammetry |
| title | <b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b> |
| title_full | <b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b> |
| title_fullStr | <b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b> |
| title_full_unstemmed | <b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b> |
| title_short | <b>Voltammetric investigation of the distribution of hydroxo-, chloro-, edta and carbohydrate complexes of lead, chromium, zinc, cadmium and copper: Potential application to metal speciation studies in brewery wastewater</b> |
| title_sort | b voltammetric investigation of the distribution of hydroxo chloro edta and carbohydrate complexes of lead chromium zinc cadmium and copper potential application to metal speciation studies in brewery wastewater b |
| topic | Metal speciation Carbohydrates Brewery wastewater Differential pulse voltammetry |
| url | http://www.ajol.info/index.php/bcse/article/view/21117 |
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