Efficient Removal of Dyes from Aqueous Solution by a Porous Sodium Alginate/gelatin/graphene Oxide Triple-network Composite Aerogel

A three-dimensional (3D) robust sodium alginate/gelatin/graphene oxide (SGGO) triple-network composite aerogel was designed using a "hydrophilic assembly-sustained release gelation" two-step method. The resulting SGGO aerogel has an ordered fishing net-like microstructure, low density (16.2 mg/cm(3)), high porosity (93.5%), and abundant functional groups when only 3 wt% GO was incorporated. The reinforced mechanical strength can reach 0.37 MPa and 0.12 MPa under dry and wet states, respectively, and the dry strength can still reach 0.31 MPa without a significant loss after five compression cycles. A batch adsorption experiment was performed as a function of pH, contact time and initial concentration. Adsorption behavior followed the pseudo second-order kinetic model and Langmuir isotherm, yielding the maximum monolayer adsorption capacity of 322.6 mg/g and 196.8 mg/g for Methylene blue (MB) and Congo red (CR), respectively. Moreover, thermodynamic studies indicated a spontaneous and endothermic adsorption process. After five regeneration cycles, the adsorption capacity can reach 88.4% and 86.5% of the initial values for MB and CR, demonstrating a high-performance, recyclable and promising candidate for dye wastewater treatment.