Modified graphene oxide composite aerogels for enhanced adsorption behavior to heavy metal ions

Abstract

Exploiting adsorbents with high adsorption activity, good durability and low cost is still the core focus of water pollution treatment. In this study, sodium alginate (SA), graphene oxide (GO), and β-cyclodextrin (βCD) were used as raw materials to frame a composite aerogel with an orderly 3D network structure by a sol-gel and freeze-drying method. The incorporation of (graphene oxide)-β-cyclodextrin (GO-βCD) could make SA molecules have higher cohesion and create more active sites for adsorbates. The temperate ratio of GO-βCD and SA to be integrated was also discussed in this work. When GO-βCD was 4 wt% (i.e., SA/GO-βCD-4), the compress performance of the composite aerogel could be 37.97% higher than the original pure SA aerogel, and the saturated adsorption capacity for Cu2+ and Cd2+ reached up 148.49 and 174.85 mg/g. It shows that SA/GO-βCD-4 composite aerogels have excellent adsorption properties for metal ions. The test data was fitted to reveal the adsorption mechanism. The adsorption kinetics of the pseudo-second-order kinetic model and Langmuir isotherm models were identified to coincide with the adsorption behavior of the modified aerogel. Comprehensively, the synthesis of the samples could pave a new way for versatile adsorbents.