pH-Responsive Eco-Friendly Chitosan–Chlorella Hydrogel Beads for Water Retention and Controlled Release of Humic Acid

For improving the mechanical strength of controlled release fertilizer (CRF) hydrogels, a novel material Chlorella was employed as bio-based filler to prepare chitosan–chlorella hydrogel beads with physical crosslink method. Here, synthesis mechanism investigated, and exhibited enhanced stability under centrifugation sonication than pure chitosan beads. brought more abundant functional groups original hydrogel, hence, represented greater sensitivity controllable response external factors including pH, salt solution, temperature. In distilled water, 40 wt% reached largest water absorption ratio 42.92 g/g. Moreover, kinetics process swelling behavior were evaluated, loading releasing humic acid by carrier pH-dependent adjustable, which exhibit potential in field biomaterials.