Preparation of porous diethylene triamine reduced graphene oxide aerogel for efficient pollutant dye adsorption

Diethylene triamine (DETA) reduced graphene oxide aerogel (DRA) was fabricated by self-assembly and freeze-drying method. The effects of preparation processes, including reduction temperature and DETA concentration, on the aerogel performance were investigated. It can be found that the density of the as-prepared DRA-8 is as low as 11. 15 mg/cm 3 when the DETA concentration is 16 µL/mL, and the reduction temperature is 95 °C. And the DRA-8 has abundant macro-pores between 10 and 100 μm in size. Meanwhile, using azo dyes as adsorbates, the adsorption capacities of DRA-8 under different process conditions were examined. The results demonstrate that the pseudo-second-order model and the Langmuir isotherm model agree well with the experimental data. At 298 K, the adsorption capacities for methyl orange (MO) and methylene blue (MB) are up to 227.24 and 266.82 mg/g, respectively. The thermodynamics analysis presents the adsorption belongs to a spontaneous thermodynamic reaction. The adsorption mechanism of DRA-8 for MO and MB was also explained. Meantime, DRA-8 can have a high adsorption capacity for MB and MO after multiple cycles. All of these point to the possibility of using DRA-8 as a suitable adsorbent material for dye elimination from aqueous environments.