Toward Financially Viable Phytoextraction and Production of Plant-Based Palladium Catalysts

Abstract

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 Pd. To advance this technology, species suitable for in-the-field application: mustard, miscanthus, and 16 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 toward, the development of field-suitable species that concentrate catalytically 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.

Phytoremediation Potential of Fast-Growing Energy Plants: Challenges and Perspectives – a Review

“…Miscanthus and 16 willow species and cultivars were tested in a palladium-contaminated synthetic and minesourced tailings. The results indicated the possibility of using the plants for accumulating palladium and decreasing the overall environmental impacts associated with its extraction [153].…”

Conservation of Critical Elements of the Periodic Table

“…However, such systems have struggled to be commercially viable . It has recently been demonstrated that palladium on carbon catalysts from plants (produced through phytomining) are worth five times more than the value of the pure metal . Using nanoparticles in planta adds value and reduces energy inputs and processing costs for the production of catalysts .…”

“…It has recently been demonstrated that palladium on carbon catalysts from plants (produced through phytomining) are worth five times more than the value of the pure metal . Using nanoparticles in planta adds value and reduces energy inputs and processing costs for the production of catalysts . Although the use of the plant after metal uptake has been demonstrated as an effective material for the production of catalysts, the thermal treatment of the metal‐laden biomass could also generate bio‐based chemicals as part of a biorefinery.…”

Preparation of High-Performance CdS@C Catalyst Using Cd-Enriched Biochar Recycled From Plating Wastewater

“…A promising disposal method for metal-enriched hazardous waste is upcycling in the form of high value-added products (Harumain et al, 2017;Cui et al, 2018;Ye et al, 2019). In principle, noble metals (e.g., Ni, Au, Cu, and Pt) can be directly recovered by incineration/pyrolysis or leaching (Keller et al, 2005;Zhang et al, 2014;Guilpain et al, 2018).…”

“…However, Cd is not a valuable heavy metal, and it is not economically viable to extract it directly from Cd-accumulated hazardous waste (Sadegh et al, 2007;Chen et al, 2019c). Interestingly, some metal-enriched hazardous wastes have shown great potential for upcycling as catalysts (Parker et al, 2014;Harumain et al, 2017;Chen et al, 2019c,d). For example, palladium in metal-enriched hazardous wastes can be recovered in the form of high-value carbonsupported catalysts (Parker et al, 2014;Harumain et al, 2017).…”