Mild preparation of amino-functionalized graphene oxide-based recyclable aerogel to efficiently adsorb methyl orange

With acrylamide (AM), methacryloxyethyltrimethyl ammonium chloride, polyethyleneimine ethoxylated (PEI), and graphene oxide (GO) as the raw materials, an amino-functionalized GO-based recyclable composite aerogel (CPAM/PEI/GO, CPAM = cationic polyacrylamide) was constructed by a mild method. In order to verify successful preparation of the composite aerogel, it was characterized by Fourier infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Since CPAM/PEI/GO had negative charge on the surface, methyl orange (MO), an anionic dye, was chosen as the adsorption molecule to study adsorption performance of the aerogel. The results showed that CPAM/PEI/GO possessed efficient adsorption performance toward MO, and the equilibrium adsorption capacity could attain 677.55 mg/g at 303 K. The adsorption process for CPAM/PEI/GO toward MO could be well simulated by pseudo-second-order kinetic and Langmuir adsorption model, and the adsorption was a spontaneous process. The main driving forces of adsorption process were hydrogen bonding, pi-pi conjugate interaction, and electrostatic interaction. Even after six adsorption-desorption cycles, the equilibrium adsorption capacity of CPAM/PEI/GO aerogel still could retain 536.99 mg/g, which indicated that the aerogel exhibited good regenerability. The composite aerogel might provide a new inspiration for the preparation of amino-functionalized GO-based aerogels and broaden their application field in wastewater treatment.