Selective removal of diethanolamine from methyldiethanolamine solution using chemically reduced single-layer graphene and activated carbon

The adsorption capacity of chemically reduced graphene (CRG) in selective removal of diethanolamine (DEA) from a mixture of methyldiethanolamine (MDEA) in aqueous solutions was evaluated and compared with commercially available activated carbons using batch studies. Four equilibrium isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin–Radushkevish and three different kinetics models such as Pseudo-first order, Pseudo-second order and Intra-particle diffusion were applied. The maximum uptake capacity for DEA using CRG at 296 K (250.0 mg/g) was high compared to two selected activated carbons (1.05 and 0.559 mg/g). The adsorption of DEA was found to be spontaneous and endothermic process with all the adsorbents.