Characterization and Application of Cellulose-Humic Acid-Based Composite Superabsorbent Hydrogel

Using acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and N,N'-methylenebisacrylamide (MBA) along with leaf cellulose and weathered coal humic acid, a leaf cellulose-humic acid-based superabsorbent hydrogel was synthesized through a water-solution polymerization initiated by potassium persulfate. FTIR analysis confirmed the successful preparation of the composite hydrogel. SEM analysis showed the presence of numerous deep pores and pore structures on the surface of the composite superabsorbent hydrogel. TG analysis indicated that a good thermal stability of the composite hydrogel. The water absorption capacity, water retention ability, salt resistance, and water release performance of hydrogels were studied. Performance tests demonstrated that the water retention rate of superabsorbent hydrogel was 79.2% after 24 h at room temperature and 22.5% after 72 h. Sandy soil absorption release tests showed that the superabsorbent hydrogel could release water into sandy soil continuously, providing long-term water supply. In plant growth experiments, the incorporation of the superabsorbent hydrogel enhanced plant growth height, prolonged wilting time, and significantly promoted plant growth and development.