Dendritic bifunctional nanotraps inside SBA‐15 for highly efficient removal of selected nonsteroidal anti‐inflammatory drugs from wastewater

Abstract

Large‐pore mesoporous SBA‐15 materials were functionalized with dendritic bifunctional ligands to achieve efficient adsorption of nonsteroidal anti‐inflammatory drugs (NSAIDs) in aqueous solution mainly through a combination of anion‐exchange ability of quaternary ammonium cations and π‐π interaction capability of oxygen activated phenyls. The synthesis of such a dendritic ligand starts from propylamine on SBA‐15 followed by consecutive amine‐epoxy reactions with resorcinol diglycidyl ether (RDGE) and methylamine, and then amination of terminal epoxy with trimethylamine. The results from Fourier‐transform infrared spectroscopy, nitrogen adsorption–desorption measurements and elemental analysis reveal that the bifunctional dendritic nanotraps have been created successfully inside the mesochannels of SBA‐15 (DNT@SBA‐15). Adsorption kinetics for NSAIDs was very rapid following a pseudo‐second‐order kinetic model, and adsorption isotherms were fitted well by the Langmuir isotherm model. Notably, DNT@SBA‐15 demonstrated remarkably high adsorption capacities for NSAIDs, with maximum values of 1037.3 mg g−1 for ibuprofen, 821.3 mg g−1 for naproxen and 781.3 mg g−1 for diclofenac at pH 7.0. The adsorption was presumed to be governed by a dual‐interaction mechanism including electrostatic and van der Waal's interactions. This study demonstrates that the developed dendritic anion‐exchanger can be a promising material for removing NSAIDs adsorption from environmental water.