Enhanced adsorption capacity of cellulose hydrogel based on corn stalk for pollutants removal and mechanism exploration

Corn stalk is a biomass resource that is discarded in quantity. The reuse of biomass for pollution control is a promising method to utilize the wastes to treat wastes. The main component of corn stalk is cellulose, which is a fin material to prepare hydrogels. However, the low adsorption capacity of cellulose hydrogel limits its appli-cation in wastewater treatment. In our study, water-soluble polysaccharides were used to enhance the cellulose hydrogel adsorption capacity. Pectin, chitosan, sodium alginate, and three heteropolysaccharides (from corn stalk, ginkgo folium, and licorice) were crosslinked with corn stalk cellulose to form composite hydrogels. The morphological and structural performances of hydrogels were evaluated using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analyzer (TGA), etc. The specific surface area, water retention capacity, and thermally resistance of hydrogels were improved after the modifi-cation. Methylene blue (MB), Pb2+, and tetracycline (TC) were taken as model contaminants. The MB adsorption was enhanced from 53.03 to 328.36 mg/g; the Pb2+ adsorption was enhanced from 1.73 to 30.03 mg/g; the TC adsorption was enhanced from 0.50 to 16.49 mg/g. Moreover, the adsorption mechanisms were discussed. This work provides a way to treat the wastes with wastes.

Automated summary

In this study, water-soluble polysaccharides were used to enhance the adsorption capacity of cellulose hydrogel, forming composite hydrogels by crosslinking with corn stalk cellulose. The modified hydrogels showed improved specific surface area, water retention capacity, and thermal resistance. The method provides a way for wastewater treatment and enhances the adsorption capacity of methylene blue, lead ions, and tetracycline.