Research ArticleOpen AccessGoogle Scholar indexed
Efficiency of Crude <i>α</i>-Cyclodextrin in Gold Recovery from Electronic Waste and Soil
Department of Chemistry, Makerere University, Kampala, Uganda
Department of Chemistry, Makerere University, Kampala, Uganda
Department of Chemistry, Makerere University, Kampala, Uganda
Department of Chemistry, Faculty of Science, Kabale University, Kabale, Uganda
Department of Chemistry, Makerere University, Kampala, Uganda
- 1 Department of Chemistry, Makerere University, Kampala, Uganda
- 2 Department of Chemistry, Makerere University, Kampala, Uganda
- 3 Department of Chemistry, Makerere University, Kampala, Uganda
- 4 Department of Chemistry, Faculty of Science, Kabale University, Kabale, Uganda
- 5 Department of Chemistry, Makerere University, Kampala, Uganda
Green and Sustainable Chemistry·Volume 12 (2022)·Pages 73–82·Published 9 August 2022·DOI10.4236/gsc.2022.123006
Copy link · social · email
Abstract
In this study, the metal coordination ability of alpha-cyclodextrin ( α -CD) was employed to complex gold and thus isolate and extract it from different matrices of acid-digests of electronic waste and soil. The crude α -CD used was extracted from cassava and yam starch of the non-edible plant species using E. coli α -cyclodextrin glucanotransferase ( α -CGTase), with yields ≥ 62%. The reaction was monitored progressively by ultraviolet-visible spectroscopy and checked with infrared spectroscopy (IR) for the presence of α -CD. The crude α -CD extract without need for purification was refluxed with gold containing-electronic waste and soil predigested in a mixture of NaBr/HNO 3 for 4 - 7 days. Recoveries of up to 22.9% and 70.8% gold were achieved from electronic waste and soil, respectively using 0.1 M α -CD. This approach is cheap, effective, and environmentally benign.
KeywordsStarch<i>α</i>-CyclodextrinElectronic WasteSoilGold
- do Nascimento, M.R. and Lourenco, A.M.G. (2015) Chemical Characterization of Auriferous Ores from the Brazilian State of Paraiba. The Journal of Minerals and Materials Characterization and Engineering, 3, 9-14. https://doi.org/10.4236/jmmce.2015.31002
- Veiga, M.M., Maxson, P.A. and Hylander, L.D. (2006) Origin and Consumption of Mercury in Small-Scale Gold Mining. Journal of Cleaner Production, 14, 436-447. https://doi.org/10.1016/j.jclepro.2004.08.010
- Bender, M.L. and Komiyama, M. (1978) Cyclodextrin Chemistry. Springer Verlag, Berlin. https://doi.org/10.1007/978-3-642-66842-5
- Saenger, W. (1980) Cyclodextrin Inclusion Compounds in Research and Industry. Angewandte Chemie, 19, 344-362. https://doi.org/10.1002/anie.198003441
- Atwood, L., Davies, J.E.D., MacNicol, D.D. and Vogtle, F. (1996) Comprehensive Supramolecular Chemistry. Pergamon Press, Oxford.
- Yu, E.K.C., Aoki, H. and Misawa, M. (1988) Specific Alpha-Cyclodextrin Production by a Novel Thermostable Cyclodextrin Glycosyltransferase. Applied Microbiology and Biotechnology, 28, 377-379. https://doi.org/10.1007/BF00268199
- Stoddart, J.F. and Zarzycki, R. (1988) Cyclodextrins as Second-Sphere Ligands for Transition Metal Complexes. Recueil des Travaux Chimiques des Pays-Bas, 107, 515-528. https://doi.org/10.1002/recl.19881070902
- Matsui, Y., Kurita, T. and Date, Y. (1972) Complexes of Copper(II) with Cyclodextrins. Bulletin of the Chemical Society of Japan, 45, 3229-3229. https://doi.org/10.1246/bcsj.45.3229
- Matsui, Y., Kurita, T., Yagi, M., Okayama, T., Mochida, K. and Date, Y. (1975) The Formation and Structure of Copper(II) Complexes with Cyclodextrins in an Alkaline Solution. Bulletin of the Chemical Society of Japan, 48, 2187-2191. https://doi.org/10.1246/bcsj.48.2187
- Breslow, R. and Dong, S.D. (1998) Biomimetic Reactions Catalyzed by Cyclodextrins and Their Derivatives. Chemical Reviews, 98, 1997-2012. https://doi.org/10.1021/cr970011j
- Breslow, R. and Nesnas, N. (1999) Burst Kinetics and Turnover in an Esterase Mimic. Tetrahedron Letters, 40, 3335-3338. https://doi.org/10.1016/S0040-4039(99)00460-8
- Francesco, B., Diego, L.M., Carlo, P., Enrico, R., Michele, S. and Graziella, V. (2009) Selectively Functionalized Cyclodextrins and Their Metal Complexes. Chemical Society Reviews, 38, 2756-2781. https://doi.org/10.1039/b718436k
- Liu, Z., Frasconi, M., Lei, J., Brown, Z.J., Zhu, Z., Cao, D. and Botros, Y.Y. (2013) Selective Isolation of Gold Facilitated by Second-Sphere Coordination with α-Cyclodextrin. Nature Communications, 4, 1-9. https://doi.org/10.1038/ncomms2891