Carboxymethylcellulose/sodium alginate aerogel beads from agricultural waste for sustainable controlled nutrient release

This study aimed to develop biopolymeric aerogel beads from carboxymethylcellulose, derived from durian peel waste, and sodium alginate for use as controlled‐release fertilizers. The beads were synthesized through homogenization, ionic gelation and freeze‐drying, with NPK fertilizer incorporated during preparation. Structural analyses (scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy) confirmed an interconnected porous network and stable chemical interactions between the biopolymers, supporting both encapsulation and sustained release. Mechanical testing showed that beads with 1.5 g of sodium alginate achieved an optimal compressive modulus of 47 kPa, providing sufficient strength for handling while maintaining porosity for nutrient diffusion. Nutrient release experiments demonstrated a gradual and sustained release of nitrogen (59.16%), phosphorus (59.85%) and potassium (60.17%) over 30 days, reducing leaching losses and ensuring better nutrient availability for plants compared to conventional fertilizers. In addition, the beads exhibited high water retention capacity, which is particularly beneficial in drought‐prone soils. By converting agricultural residues into functional materials, this work not only addresses waste vaporization but also offers a sustainable and environmentally friendly strategy for precision nutrient delivery in modern agriculture.