Preparation of porous graphene oxide by chemically intercalating a rigid molecule for enhanced removal of typical pharmaceuticals

Porous graphene oxide (GO) adsorbents were successfully prepared by connecting GO sheets with tetrafluoroterephthalonitrile (TFT) or decafluorobiphenyl (DFB) through a nucleophilic aromatic substitution reaction. Textural characterization indicated that the enlarged surface area and pore size of the as-synthesized GO-based adsorbents were favorable for the diffusion and adsorption of the typical pharmaceuticals. The GO reacted with 20 mmol/L DFB (GO-DFB20) exhibited the highest removal for six pharmaceuticals among the prepared adsorbents, and can be separated easily. The adsorption capacities of GO-DFB20 for carbamazepine (CBZ), sulfamethoxazole (SMZ), sulfadiazine (SDZ), ibuprofen (IBP), paracetamol (PCT) and phenacetin (PNT) were 340.5, 428.3, 214.7, 224.3, 350.6 and 316.1 μmol/g, respectively. The adsorption kinetics of PCT on the GO-DFB20 was faster than SMZ. According to the Langmuir fitting, the maximum adsorption capacities of GO-DFB20 for SMZ and PCT were 749.6 and 663.9 μmol/g, respectively. The spent GO-DFB20 was successfully regenerated by methanol with little loss of adsorption capacity in five successive adsorption cycles. This study shows that the porous GO adsorbent has a promising application for the removal of typical pharmaceuticals from water or wastewater.

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