Fecha de publicación: -- Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Lignin-grafted poly(acrylic acid-co-acrylamide) microspheres prepared via suspension polymerization exhibit uniform spherical morphology, high water retention, efficient Cu2+/Cd2+/Ni2+ adsorption, and excellent biodegradability. With sustained urea release and cycle stability, these eco-friendly microspheres promote corn growth, offering a sustainable strategy for soil improvement and heavy metal remediation.

ABSTRACT
Biodegradable water-absorbing resins hold significant potential in mitigating soil-related issues and advancing sustainable agriculture. Lignin, being abundant, eco-friendly, and biodegradable, possesses multiple active functional groups in its molecular structure, making it an ideal raw material for developing high-performance superabsorbent resins. To further improve water absorption efficiency, dispersibility, and soil compatibility, lignin-based polyacrylamide superabsorbent resin microspheres were successfully synthesized via suspension polymerization. The resulting microspheres exhibited an average particle size (D50) of 13.64 μm, with absorption capacities of 664 g/g in distilled water and 188 g/g in 0.09% NaCl solution. Moreover, the adsorption capacities for heavy metal ions-Cu2+, Cd2+, and Ni2+-were measured at 146.4, 97.99, and 89.09 mg/g, respectively. After three absorption-desorption cycles, the saturated liquid absorption capacity remained at 68% of its initial value. Treatment of soil with the resin microspheres for 30 days resulted in a volume expansion from 400 to 490 mL, representing a 22.5% increase. The resin also demonstrated favorable biodegradability in soil, with a degradation rate of 47.2% over 28 days, thereby minimizing the risk of long-term secondary contamination. These findings indicate that lignin-poly (acrylic acid-acrylamide) superabsorbent resin microspheres hold considerable promise for applications in modern sustainable agriculture.