Meet John Liu, the student who used corn stalks and wheat straw to recover lithium from diluted water |

Lithium is a crucial ingredient in rechargeable batteries, but recovering it from dilute sources can be difficult and energy-intensive. John Liu, a high school student from St.

Paul, Minnesota, addressed that problem by looking at the materials that typically remain after harvest: corn stalks and wheat straw. Their project, titled ‘Passive preconcentration of lithium by capillary evaporation from dilute brines using functionalized corn stalk pith and wheat straw scaffolds’, explored whether agricultural waste could help concentrate lithium from dilute brines. The project earned Liu a spot among Minnesota finalists for the 2026 Regeneron International Science and Engineering Fair and a Gold Award at the Minnesota State Science and Engineering Fair.

The Minnesota Academy of Sciences includes his work among the best high school projects at the fair and identifies him as a St. Paul student.

How John Liu turned agricultural waste into a material

Liu’s project focused on two materials that are abundant agricultural byproducts: corn stalk pith and wheat straw. Instead of simply treating them as waste, he investigated their potential as scaffolds for a process that could passively concentrate lithium from dilute brines. The project title describes the approach as passive preconcentration of lithium by capillary evaporation. In practical terms, the research combines the ability of plant structures to move liquid through tiny spaces with evaporation to increase the concentration of lithium in a dilute solution.

Corn stalk pith and wheat straw were functionalized for this purpose, converting natural agricultural material into structures designed for lithium recovery.

The idea is notable because it connects two very different problems: the growing need for lithium and the huge amounts of agricultural waste produced after harvesting. Instead of relying solely on conventional materials, Liu investigated whether plant-based waste could be part of a lower-cost route to concentrating lithium. The Minnesota Academy of Sciences identifies Liu’s project as environmental engineering and lists it as HS-ENEV-500.

Why it is difficult to recover lithium from diluted brines

Lithium can be found in brines in concentrations that make direct recovery difficult. When the concentration is low, separating lithium from a large volume of water requires an efficient method to first bring the lithium into a more concentrated form. That’s where Liu’s research focused. Instead of trying to extract lithium immediately from a very dilute solution, their system was designed around preconcentration.

Plant-derived scaffolds provide a structure through which brine can move, while evaporation removes water and leaves dissolved lithium increasingly concentrated. The choice of corn stalk pith and wheat straw also gives the project a sustainability angle. Both are agricultural waste rather than specially designed raw materials. Liu’s work therefore investigates whether materials that already exist as crop waste can be adapted for a high-value environmental application.

Their project was strong enough to earn a Gold Award at the 2026 Minnesota State Science and Engineering Fair. The Minnesota Academy of Sciences says Gold Awards recognize projects that are among the top 5% presented at the state fair.

From a to international competition

Liu’s project went beyond the state competition. He was named one of Minnesota’s 2026 finalists for the Regeneron International Science and Engineering Fair, along with other high school researchers across the state.

Later the project competed in the international fair; The ISEF Grand Awards included Liu as the second prize winner in the environmental engineering category, receiving $2,400. The Minnesota Academy of Sciences also reported that Liu won second place in ISEF and received the Chief of Naval Research Scholarship Award among special awards won by Minnesota students.

What began as an investigation into whether corn stalks and wheat straw could help concentrate lithium from dilute brines eventually became an internationally recognized research project. Liu’s work demonstrates how everyday agricultural waste can become the starting point for a much more ambitious scientific question: whether farm waste can help recover a material increasingly important for modern energy technology.