They could potentially do pyrolysis of the biomass (after harvest) and then extract the heavy metals from the resulting char. e.g. https://www.sciencedirect.co

They could potentially do pyrolysis of the biomass (after harvest) and then extract the heavy metals from the resulting char. e.g. https://www.sciencedirect.com/science/article/abs/pii/S0961953402000740 https://www.sciencedirect.com/science/article/abs/pii/S09619... https://www.sciencedirect.com/science/article/abs/pii/S0921344917303178 https://www.sciencedirect.com/science/article/abs/pii/S09213...