Supercritical assisted synthesis of controlled release formulations for sustainable agriculture

Water scarcity, soil degradation, and inefficient agrochemical delivery are critical constraints to sustainable and climate resilient agriculture. This study presents the synthesis of controlled release formulations (CRFs) using supercritical carbon dioxide (SCC) as an environmentally sustainable processing approach that eliminates toxic organic solvents. The designed CRFs aim to enhance soil water retention, enable controlled herbicide delivery, and undergo complete biodegradation without generating harmful residues. Biomass processing involved sequential dewaxing and fractionation, yielding 7.48% wax, 44.3% cellulose, 48% lignin, and 0.19% hemicellulose, confirming its suitability as a renewable and sustainable structural framework. Herbicide loading was subsequently achieved using SCC as a solvent free and green medium. The CRFs were synthesised by incorporating the herbicide into a pre-synthesized biohydrogels matrix via polymerization of acrylamide, using bisacrylamide as the crosslinker and AIBN as the initiator, followed by grafting onto biomass derived components. Morphological and physicochemical analyses verified the formation of a network structure loaded with herbicide and influenced by SCC processing parameters. The results demonstrates that under simulated soil conditions, the synthesized CRFs exhibited up to 200% water absorption capacity, high porosity, and progressive biodegradation driven by microbial activity. Electrochemical modelling of release kinetics demonstrated a sustained and controlled herbicide release profile, effectively reducing leaching and environmental persistence. Overall, these multifunctional CRFs function as eco-friendly soil conditioners that integrate water conservation with efficient herbicide delivery, offering a scalable and low impact strategy for sustainable and climate resilient agricultural systems.

Jyoti Maheshwari is a research scholar at G. B. Pant University of Agriculture and Technology, Uttarakhand, India. Her entire academic journey has been completed in India. She obtained her bachelor's degree in science (2018) and master's degree in science (2020) from D.S.B. Campus, Nainital, Uttarakhand, and is currently pursuing a Doctor of Philosophy under the guidance of Professor M. G. H. Zaidi in the Department of Chemistry at G. B. Pant University of Agriculture and Technology.

Her research contributions span polymer science, electrochemistry, and supercritical technology. She serves as the Principal Investigator of a project supported by the Department of Science & Technology, focused on advancing research dissemination in science and technology. Jyoti Maheshwari is a meticulous, analytical, and problem-solving researcher with seven scholarly publications, including research articles and book chapters.