Efficient and convenient purification strategy using maltodextrin-based nanosponges for rapid removal of cationic dyes

Developing new adsorbents and studying their adsorption mechanisms can greatly assist in addressing environmental pollution issues. Herein, the maltodextrin-based nanosponges (MD-SPs) were facilely synthesized by esterification reaction at room temperature. The porous features, nanostructure, and swelling capacities of the resulting MD-SPs can be regulated by altering the crosslinking agent, which controls the adsorption properties. Using nine cationic dyes as model adsorbates, the results showed that MD-SPs could adsorb a large amount of cationic dyes in a short time. Especially, MD-SP-1 could rapidly adsorb over 90 % of most cationic dyes within 3 min, and the maximal adsorption quantity (Q_m) of cationic red X-GRL (CRX) was as high as 2137.81 mg/g. The adsorption behaviors were meticulously investigated by multiple adsorption kinetic and thermodynamic models. Furthermore, the integrated analysis of experimental and theoretical calculations results demonstrated that the electrostatic force, hydrogen bonding, hydrophobic interaction, cation-π interaction, and π-π stacking may collectively facilitate the capture of dye molecules. Notably, the absorbent offered excellent anti-interference capabilities, high stability, and reusability, making it an ideal adsorbent for the rapid and batch treatment of dye wastewater. These discoveries may provide valuable references for the theoretical and practical study of adsorbents and offer new insights into the development of advanced maltodextrin-based adsorbents.