Ice segregation induced self-assembly of graphene oxide into graphene-based aerogel for enhanced adsorption of heavy metal ions and phenolic compounds in aqueous media

In this study, we reported the synthesis of graphene oxide aerogel (GOA) through ice segregation induced self-assembly of GO sheets. The formation mechanism of GOA was studied via Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller surface area. The GOA with GO concentration of 10 mg/mL was applied as an adsorbent to remove heavy metal ions (Cd2+, Ni2+). The adsorption processes of GOA for Cd2+, Ni2+ fitted well with pseudo-second-order kinetics and Langmuir isotherm models. The maximum adsorption capacities for Cd2+ and Ni2+ were determined to be 108.70 and 91.74 mg/g, respectively. Moreover, the electrostatic attraction was found to be the main interaction between GOA and Cd2+, Ni2+. The adsorption of phenolic compounds (phenol and bisphenol A) was studied to expand the adsorption applications of GOA. In addition, The maximum adsorption capacities for phenol and bisphenol A were determined to be 129.37 and 64.76 mg/g, respectively. Therefore, GOA has the potential to be used as a highly efficient adsorbent for the treatment of heavy metal ions and phenolic compounds from water.