Waste-derived lignin-sulfur coatings for slow-release fertilizers
A sustainable coating platform using waste-derived lignin and sulfur for controlled nutrient release in fertilizers. This solvent-free method reduces brittleness and improves coating integrity, offering a cost-effective alternative to traditional methods.
Overview
The waste-derived lignin-sulfur coating platform offers a revolutionary approach to slow-release fertilizers by utilizing abundant waste materials in a solvent-free process. This innovative technology enables a sustained nutrient release by forming a protective coating around fertilizer granules. The use of lignin and sulfur, both industrial by-products, not only reduces environmental impact but also lowers production costs compared to conventional solvent-dependent methods.
Technical specifications
The coating is created through inverse vulcanization, a method that combines elemental sulfur with lignin derivatives to form a melt-processable material. This eliminates the need for hazardous solvents and involves less energy-intensive processing. The resulting material has a low free-sulfur content (<8 wt%) and a tunable crosslinked network, which addresses common issues like brittleness and coating defects. The process is adaptable to various fertilizer granules, allowing for substrate-specific development of coating integrity, thickness, and nutrient release behavior.
Technology readiness level
Currently at TRL 4, this technology has been validated at the bench scale with plans for further optimization and testing. Over 6–9 months, the project aims to refine formulations, apply coatings, and validate performance through various testing methods, including SEM analysis and nutrient-release profiling. Collaboration is sought for scaling and further development.
About University of Tennessee, Knoxville
UT offers a partnership model that reduces risk, accelerates time-to-value, and supports long-term growth strategies for industry—providing an attractive platform for companies seeking to formalize collaboration and establish a long-term presence in the East Tennessee region. By aligning institutional investment with regional and national priorities, UT provides a stable and effective platform for industry collaboration, technology deployment, and sustained economic impact.
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