Study on the Green Extraction Process of Lignin and the Effect of its Synthesized Hydrogel Microspheres on Seed Germination

Hydrogel is a kind of polymer material with water absorption performance, which can absorb and fix a large amount of water. Such materials are usually composed of cross-linked polymers whose cross-linked structure can form a three-dimensional network that allows water molecules to be absorbed and stored. After a variety of preparation processes, lignin hydrogel microspheres have played an important role in improving soil quality, promoting plant growth and improving environmental quality, and have broad market prospects. The hydrogel prepared by sodium alginate and lignin has excellent performance, mild reaction conditions, and can effectively avoid the deactivation of active substances. In this study, sodium alginate extracted from kelp and lignin extracted from wheat straw were innovatively used to prepare hydrogels. The results of thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) confirmed the successful extraction of sodium alginate and lignin. Lignin@SA-PVA (SPL)microspheres were prepared by dropping method, and the expansion rate was 302.58 g/g. In this study, lignin hydrogel microspheres were applied to wheat seed germination experiments to verify its promoting effect on wheat seed germination and growth, which provided new ideas for the development of new hydrogel microsphere materials and laid a theoretical foundation for the popularization and application of such materials in the field of agriculture.