Towards financially viable phytoextraction and production of plant-based palladium catalysts

Zakuan A.S. Harumain, Helen L. Parker, Andrea Muñoz García, Michael J. Austin, Con Robert McElroy, Andrew J. Hunt, James H. Clark, John A. Meech, Christopher W.N. Anderson, Luca Ciacci, T. E. Graedel, Neil C. Bruce*, Elizabeth L. Rylott

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Although a promising technique, phytoextraction has yet to see significant commercialization. Major limitations include metal uptake rates and subsequent processing costs. However, it has been shown that liquid-culture-grown Arabidopsis can take up and store palladium as nanoparticles. The processed plant biomass has catalytic activity comparable to that of commercially available catalysts, creating a product of higher value than extracted bulk metal. We demonstrate that the minimum level of palladium in Arabidopsis dried tissues for catalytic activity comparable to commercially available 3% palladium-on-carbon catalysts was achieved from dried plant biomass containing between 12
and 18 g·kg-1 39 Pd. To advance this technology, species suitable for in-the-field application: mustard, miscanthus and sixteen willow species and cultivars, were tested. These species were able to grow, and take up, palladium from both synthetic and mine-sourced tailings. Although levels of palladium accumulation in field-suitable species are below that required for commercially available 3% palladium-on-carbon catalysts, this study both sets the target, and is a step towards, the development of field-suitable species that concentrate catalytically-
45 active levels of palladium. Life cycle assessment on the phytomining approaches described here indicates that the use of plants to accumulate palladium for industrial applications has the potential to decrease the overall environmental impacts associated with extracting palladium using present-day mining processes.
Original languageEnglish
Pages (from-to)2992-3000
Number of pages9
JournalEnvironmental science & technology
Issue number5
Early online date13 Feb 2017
Publication statusPublished - 7 Mar 2017

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