Synthesis and application of graphene aerogel as an adsorbent for water treatment

Abstract

In this research, graphene aerogel (GA) was fabricated by chemical reduction method, in which ethylenediamine (EDA) was used as a reducing and functionalising agent. The characterisation of GA was studied by density, field-emission scanning electron microscope, Brunauer-Emmett-Teller (BET) specific surface area, Fourier transform infrared spectroscopy, and X-ray diffraction. The results of the analysis showed that GA exhibits low density, ranging from 4-8 mg/cm³, high porosity, and BET specific surface area changes from 176 to 1845 m²/g. It was found that the suitable content of EDA on the synthesis of GA is 30 µl. The obtained GA was used as an adsorbent for removal of oils and methylene blue (MB) from aqueous solutions. The maximum adsorption capacities of GA for lubricant and crude oils are 160 g/g and 110 g/g respectively. The effecting factors including pH, contact time, and initial concentrations on the adsorption capacity of GA for MB were investigated. The adsorption process of MB onto GA followed the pseudosecond-order kinetic and well-fitted to Langmuir isotherm model. The maximum adsorption capacity for MB from linear Langmuir model was calculated to be 212.76 mg/g at pH 7. Accordingly, GA could be used as a potential adsorbent for removal of oils and MB from water.