Author(s)

Ibrahim Karume^1*, Simon Tewolde¹, Emmanuel Tebandeke¹, Is’harq Z. T. Mukasa², Ruth Mbabazi¹

¹Department of Chemistry, Makerere University, Kampala, Uganda.
²Department of Chemistry, Faculty of Science, Kabale University, Kabale, Uganda.

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/HNO₃ 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.

Starch, α-Cyclodextrin, Electronic Waste, Soil, Gold

Karume, I. , Tewolde, S. , Tebandeke, E. , Mukasa, I. and Mbabazi, R. (2022) Efficiency of Crude α-Cyclodextrin in Gold Recovery from Electronic Waste and Soil. Green and Sustainable Chemistry, 12, 73-82. doi: 10.4236/gsc.2022.123006.