What method can be used to derive metals from the soil after phytoextraction?

Phytoextraction is a process where plants are used to absorb metals from the soil through their roots and accumulate them in their above-ground tissues. After harvesting these plants, one effective method to recover the metals is through burning the biomass of the plants. This process turns the organic material into ash, concentrated with the metals absorbed by the plants.

Burning the plants reduces their volume and helps separate the metals from the organic matter, allowing for easier extraction from the resultant ash. The metals can then be treated chemically to recover pure forms. This method leverages the fact that the plants have selectively taken up and concentrated the metals, making the subsequent ash rich in the desired elements.

This method aligns well with the principles of environmental management and metal recovery, as it utilizes biological processes (phytoextraction) in conjunction with thermochemical processes (burning) for efficient metal retrieval from contaminated soils. This synergy enhances the overall efficacy of soil remediation efforts.