Modular Purification Systems LLC
Rare Earths and Critical & Strategic Minerals
Value-Added Graphitic Composites
We present some of our research on the biosynthesis of graphitic lanthanides and critical minerals. We utilized phytoextraction to recover elements from e-waste leachate. We introduced a novel class of graphitic composites.
In plain language, we found a “plant-to-product” way to recycle valuable rare earth elements from waste. A small aquatic plant can absorb rare earths (like neodymium, gadolinium, erbium, europium, and yttrium) from contaminated water in about 10 days. After the plant captures these metals, we heat the dried plant material to very high temperature to convert it into a graphite-like carbon material.
The key result is that the captured rare earths help the plant-based carbon turn into a higher-quality, more “graphite-like” material—and in some cases it performs better than commercial graphite. For example, the gadolinium-based material showed higher electrical conductivity, strong energy-storage potential (capacitance), and useful magnetic behavior, which could make it a starting point for future, more sustainable materials used in electronics and even medical imaging (like MRI-related compounds).
Recycling e-waste has become a viable business opportunity due to the value of critical metals within it. Phytoextraction was explored as a sustainable method for recovering these metals, with biomass used as a precursor for graphitic material synthesis. This approach showed lower chemical consumption and energy requirements compared to traditional methods. A technoeconomic analysis and life cycle assessment of two scenarios—indium recovery from LCD screen slurry followed by pyrolysis, revealed a reduction in costs and a decrease in global warming potential per kilogram of graphite. These findings highlight the potential of biomass-based resource recovery and graphite synthesis as sustainable alternatives for critical metal recovery and value-added product creation.
Phytoextraction uses plants to pull valuable metals from contaminated soil or water into their biomass. In this study, the hyperaccumulator plant Eleocharis acicularis successfully absorbed the strategic metal indium from both indium tin oxide solutions and crushed LCD e-waste slurry—even under harsh conditions like high acidity (pH 3) and high salinity. After 15 days, the indium-rich plant biomass was pyrolyzed to produce a layered, graphite-like biocomposite with dispersed indium and higher electrical conductivity than commercial graphite. Overall, the work shows E. acicularis can recover indium from e-waste and convert it into a value-added graphite-based material.