Thiol-functionalized biochar soil amendment for reducing toxic metal contamination in food crops
Novel soil amendment using thiol-functionalized biochar to immobilize arsenic, cadmium, and mercury in agricultural soils, reducing uptake into food crops like rice while improving soil fertility and nutrient retention.
Overview
This solution addresses toxic metal and metalloid contamination in agricultural soils, a critical food safety challenge affecting crops such as rice. The approach uses biochar—a low-cost, widely available carbon material—functionalized with surface thiol groups to capture and immobilize contaminants including arsenic, cadmium, and mercury directly in the soil. By reducing plant-available concentrations of these toxic elements, the amendment limits their accumulation in edible plant tissues. Beyond contaminant control, the biochar amendment is expected to improve soil fertility through enhanced nutrient retention.
Technical specifications
Core technology:
- Biochar (BC) selected for its high surface area, low cost, and broad availability
- Surface functionalization with thiol groups, which are high-affinity ligands for arsenic, cadmium, and mercury
- Irreversible surface complexation reactions ensure stable immobilization of contaminants
- Unlike iron-based adsorbents, thiol groups remain stable under reducing conditions typical of flooded rice paddy soils
Functionalization methods under evaluation:
- Reaction with sodium sulfide solutions
- Reaction with dithiothreitol
- Reaction with methyl thioglycolate
- Reaction with 3-mercaptopropyltrimethoxysilane
- Applicable to both pristine and alkali-activated biochar
Validation approach:
- X-ray photoelectron spectroscopy (XPS) for quantitative analysis of thiol surface functionalization
- Adsorption isotherm experiments to measure performance against arsenic and cadmium
- Controlled rice growth trials in contaminated soil with and without amendment to assess plant uptake reduction
Technology readiness level
This technology is in early-stage development. The research team has prior experience producing iron-impregnated biochar for low-cost arsenic filtration, and thiol-functionalized materials are well established in industrial adsorption applications. However, existing thiol-functionalized materials are too costly for soil amendment use. The current effort focuses on developing cost-effective functionalization methods appropriate for agricultural deployment. Initial phases involve laboratory-scale synthesis and characterization, followed by pot-scale plant trials. The technology has not yet been validated at field scale.
About Cornell University
Cornell University is a comprehensive private, land-grant research university with campuses in Ithaca and New York City, combining significant scale with cross-disciplinary breadth. Industry connects through open-access user facilities and prototyping labs, pilot-scale testbeds, and a research and technology park that provide pathways from discovery to demonstration. A statewide extension network and integration with a major hospital system enable real-world deployment, while a graduate campus embedded in New York City’s tech corridor provides direct access to startups, venture investors, and corporate R&D teams. Research is supported by competitive federal funding from agencies such as the National Science Foundation, National Institutes of Health, the Department of Energy, and the U.S. Department of Agriculture. A dedicated technology transfer office streamlines IP management, licensing, startup formation, and corporate partnerships across campuses.
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