Preparation and adsorption performance of functionalization cellulose-based composite aerogel

Herein, functionalization cellulose-based composite aerogels with the addition of carboxyl cellulose nanofibers (CNF), montmorillonite (MMT) and polyethyleneimine (PEI) were fabricated by solution blending and freeze-drying technology. MMT was blended into the cellulose framework as a reinforcing agent. PEI combined with cellulose through amidation reaction, and the synergism of hydrogen bond and chemical bond helped the CNF/MMT/PEI composite aerogels (CMP) with good mechanical properties. The morphology, chemical structure and thermal stability of the CMP were characterized. The adsorption properties and mechanism of the CMP were discussed, using Congo red (CR) dye as an adsorbate. The results showed that the CMP formed a three-dimensional network structure with abundant pores. The addition of PEI regulated the surface charge distribution of cellulose and improved the adsorption performance of CMP for CR with the adsorption capacity of 3114 mg/g calculated by the Langmuir model. The adsorption process of CMP-30 for CR was more in line with the pseudo-second-order kinetic model and Langmuir isotherm model, indicating chemical adsorption of a single molecular layer. After functionalized by octadecyl trichlorosilane (OTS), the contact angle of the aerogel surface was 151.80°. Meanwhile, the CMP-30 was transformed from hydrophilic and lipophilic properties to hydrophobic and lipophilic properties.