Green valorization of durian peel waste via supercritical CO 2 ‐derived carboxymethyl cellulose ‐sodium alginate aerogels for controlled fertilizer release
Abstract
The increasing generation of agro‐industrial biomass residues and the inefficient use of conventional fertilizers have created a need for sustainable materials that support controlled nutrient delivery while promoting biomass valorization. In this study, durian peel waste was used as a cellulose source for the preparation of biodegradable carboxymethyl cellulose (CMC)/sodium alginate (SA) aerogel beads using supercritical CO 2 (Sc‐CO 2 ) pretreatment. NPK‐loaded CMC–SA aerogels with varying SA contents were fabricated and evaluated for their physical, mechanical, structural, morphological, biodegradation, and greenhouse performance. The CMC3SA1.5 formulation showed the most favorable balance of bulk density, bead yield, hardness, springiness, cohesiveness, and resilience among the tested formulations. XRD analysis showed that the aerogel beads were predominantly amorphous, in contrast to pure NPK, which exhibited sharp crystalline reflections, while CMC3SA1.5 displayed the highest peak intensity and crystallinity index, indicating improved structural organization and cross‐linking within the polymer matrix. SEM analysis further confirmed a highly porous and compact morphology with improved NPK encapsulation. In the soil burial test, all formulations exhibited progressive biodegradation over 30 days, with CMC3SA1.5 showing 59.23% weight loss, indicating a favorable balance between structural stability and biodegradability. Greenhouse studies using Capsicum annuum demonstrated that CMC3SA1.5 significantly enhanced reproductive performance, producing an average of 20 flowers by Day 90, F (7, 16) = 29.43, p < 0.0001, and 17 chilies per plant by Day 95, F (7, 16) = 88.18, p < 0.0001. The findings demonstrate that waste‐derived CMC–SA aerogels provide an effective remediation‐oriented solution for agricultural waste management and fertilizer‐associated pollution control.