Preparation of 3D multilayer composite aerogel from regenerated cellulose/polyethylenimine using ice template method for efficient anionic dye adsorption

Abstract

As modern society places a growing emphasis on sustainable development, the demand for eco-friendly adsorbent materials to effectively remediate toxic dyes in water has become increasingly critical. This study utilizes cost-effective cellulose nanofibers as the primary raw material, along with polyethyleneimine and trimethoxysilane as modifying agents. A composite aerogel adsorbent, referred to as cellulose/polyethyleneimine (CMP), is synthesized via a combination of chemical crosslinking and directional freezing employing an ice template method. The resulting CMP composite aerogel features a three-dimensional multi-walled porous structure enriched with amino and oxygen-containing functional groups, facilitating the efficient adsorption of organic dyes from aqueous solutions. The directional porous architecture and high specific surface area of the CMP composite aerogel enhance the binding affinity of organic pollutants to its active sites, thereby accelerating ion transfer. Calculations based on the Langmuir isotherm model demonstrate that the CMP composite aerogel exhibits an impressive adsorption capacity of 513.30 mg/g for the organic dye methyl orange, offering an effective solution to dye pollution in aquatic environments. The application of directional freeze-drying technology represents a green and efficient method for the fabrication of layered microporous structures. Additionally, the resulting aerogel demonstrates a low density (0.027 g/cm³) and high hydrophobicity (water contact angle 132.3°), significantly enhancing its utility. The adsorption material demonstrates considerable potential for application in the domain of water treatment, effectively removing chemical pollutants such as dyes from water.