Preparing three-dimensional graphene aerogels by chemical reducing method: Investigation of synthesis condition and optimization of adsorption capacity of organic dye

In this study, three-dimensional graphene aerogel materials fabricated by self-assembly of graphene oxide (GO) sheets with ethylenediamine was used as a reducing agent. GO sheets were briefly synthesized from graphite by improved Hummers? method, then partially reduced to create the 3D structure. The GA materials were characterized by density, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscope, and Brunauer - Emmett - Teller specific surface area. The formation mechanism of aerogel was investigated through the evaluation of reduction and drying by sublimation conditions. The adsorption process followed pseudo-second-order kinetic models. The adsorption data was well-fitted to Langmuir isotherm model. The adsorption abilities of GA for methylene blue (MB) and methyl orange (MO) were elaborated with factors including time, pH, and initial concentration. The maximum adsorption capacities of GA for MB and MO were calculated to be 221.77 and 166.66 mg/g, respectively. MO dye was chosen for estimating the simultaneous impact of different factors (pH, contact times, and initial concentration of dye) on the adsorption ability of GA and determine the ideal values for optimal performance by full factorial experimental design according to Box-Behnken designs. Moreover, the adsorption mechanism of GA for dyes also was investigated. Accordingly, GA could be applied as a potential adsorbent for the removal of dyes from aqueous media.

Automated summary

Three-dimensional graphene aerogel materials were fabricated using ethylenediamine and graphene oxide sheets, and showed high adsorption capacities for methylene blue and methyl orange. Optimal adsorption conditions and mechanisms were identified through experiments.