Hierarchical Porous Aerogels With Multiple Adsorptive Interactions for Dye Wastewater Purification

Abstract Aerogels present a huge potential for removing organic dyes from printing and dyeing wastewater (PDW). However, the preparation of aerogels with multiple dye adsorption capabilities remains a challenge, as many existing aerogels are limited to adsorbing only a single type of dye. Herein, a composite aerogel (CG/T‐rGO) with the addition of carboxymethyl chitosan, gelatin and tannic acid reduced graphene oxide (T‐rGO) was synthesized by freeze‐drying technology. The electrostatic interactions between dye molecular and GEL/CMCS (CG) networks, as well as the supramolecular interactions (H‐bonds, electrostatic interactions and π–π stacks) between T‐rGO, have endowed the aerogel with the ability to adsorb multiple types of dye, such as methylene blue (MB) and methyl orange (MO). Results exhibited that the prepared CG/T‐rGO aerogel possessed strong mechanical strength and a porous 3D network structure with a porosity of 96.33 %. Using MB and MO as adsorbates, the adsorption capacity (88.2 mg/g and 66.6 mg/g, respectively) and the mechanism of the CG/T‐rGO aerogel were investigated. The adsorption processes of aerogel for MB and MO were shown to follow the pseudo‐second‐order kinetic model and Langmuir isotherm model, indicating the chemical adsorption of a monolayer. The proposed aerogel in this work has promising prospects for dye removal from PDW.