Preparation, characterization and dye adsorption properties of ZnO aerogels

Purpose The purpose of this research paper was to explore the application of zinc oxide (ZnO) aerogels as adsorbent for removing the toxicity and solubility organic dyes from wastewater. Design/methodology/approach ZnO aerogels with three-dimensional (3D) network structure were synthesized by using sodium alginate (SA) and ZnO. Findings The maximum adsorption capacities of ZnO aerogels reached by pseudo-second-order are 19.23 and 21.37 mg/g for CR and RB, respectively. It is worth noting that the adsorption capabilities of CR and RB on ZnO aerogels decreased with temperature. The results reveal that the adsorption process between the two dyes and the ZnO aerogels involves a combination of chemical and physical interactions, indicating that the ZnO aerogels possess numerous adsorption sites. Research limitations/implications The cross-linking interaction between SA and Ca2+ was found to play a critical role in regulating the pore structure of the aerogels, which significantly enhanced dye removal efficiency. Practical implications This work presents a promising strategy for the practical treatment of wastewater containing water-soluble organic dyes. Originality/value ZnO aerogels are highly efficient and low-cost adsorbents that can be easily separated from wastewater, preventing secondary pollution and offering a sustainable approach to water purification.