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Bioinorganic Chemistry and Applications
Volume 3, Issue 1-2, Pages 29-41

Gold Binding by Native and Chemically Modified Hops Biomasses

1Envtronmental Science and Engineering Ph.D. Program, University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968, USA
2Chemistry Department, University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968, USA
3Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712-1062, USA
4Department of Crop and Soil Science, United States Department of Agriculture—Agricultural Research Service, Oregon State University, Corvallis, OR 973311, USA

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Heavy metals from mining, smelting operations and other industrial processing facilities pollute wastewaters worldwide. Extraction of metals from industrial effluents has been widely studied due to the economic advantages and the relative ease of technical implementation. Consequently, the search for new and improved methodologies for the recovery of gold has increased. In this particular research, the use of cone hops biomass (Humulus lupulus) was investigated as a new option for gold recovery. The results showed that the gold binding to native hops biomass was pH dependent from pH 2 to pH 6, with a maximum percentage binding at pH 3. Time dependency studies demonstrated that Au(III) binding to native and modified cone hops biomasses was found to be time independent at pH 2 while at pH 5, it was time dependent. Capacity experiments demonstrated that at pH 2, esterified hops biomass bound 33.4 mg Au/g of biomass, while native and hydrolyzed hops biomasses bound 28.2 and 12.0 mg Au/g of biomass, respectively. However, at pH 5 the binding capacities were 38.9, 37.8 and 11.4 mg of Au per gram of native, esterified and hydrolyzed hops biomasses, respectively.