Chitosan-coated Homoionic K-clinoptilolite: A solution for Sustainable Agriculture via Simultaneous Slow Potassium Release and Water Desodication

Increasing salinity in agricultural land poses a serious challenge to sustainable agriculture, emphasizing the urgent need for innovative soil and water management strategies. This study tested chitosan-coated homoionic K-clinoptilolite (0%, 10%, and 20% chitosan, referred to as K-C, Ch10K-C, and Ch20K-C, respectively) as an alternative solution for slow potassium release and water desalination. Clinoptilolite, a natural zeolite with ion exchange properties, was used as an effective potassium fertilizer after undergoing a K-homo-ionization process followed by chitosan coating. The chitosan coating acts as a biodegradable layer that slows the release of potassium ions, ensuring sustained nutrient availability for plants. Moreover, this combination shows potential for reducing soil sodicity by selectively releasing potassium while simultaneously adsorbing sodium ions from saline water. This process improves soil structure and enhances crop yields. Laboratory tests demonstrated that it not only prevents excessive potassium release, which could exacerbate salinity, but also significantly reduces sodium content, contributing to environmental resilience. These findings indicate that Ch10K-C and Ch20K-C are sustainable solutions for managing saline irrigation water and saline soils, offering a pathway toward environmentally friendly agricultural practices. The study utilized adsorption isotherm models for Langmuir and Freundlich, to evaluate the factors influencing Na⁺ adsorption by ChK-Cs in water. The results showed that the Freundlich model, as long as the most highly suited for the experimental data, demonstrate a heterogeneous adsorption process. Additionally, the adsorption kinetics followed a pseudo-second-order model, demonstrating the efficiency of ChK-Cs in removing sodium ions. In conclusion, homo-ionized clinoptilolite coated with chitosan serves as an excellent adsorbent to reduce sodicity, making it an ideal choice for sustainable agriculture. These materials offer a promising approach to mitigating the challenges posed by salinity in agricultural practices while promoting sustainable resource management.