One water-stable magnetic coordination polymer material (Fe3O4@PmPD–[Co-BT]) as an efficient adsorbent for rapid dye removal

Abstract

Recently, lots of organic dye adsorbents were introduced; the pollution of water bodies caused by adsorbents was an urgent problem to be solved. The modified metal–organic frameworks with magnetic properties provided a great platform for solving this disadvantage. In this study, a novel magnetic material Fe₃O₄@PmPD–[Co-BT] (Co-BT = [Co(bcpo)_0.5(tib)(H₂O)₂]_n, bcpo = 2,5-bis(4-carboxylphenyl)-1,3,4-oxadiazole, tib = 1,3,5-tris(1-imidazolyl)benzene)) was prepared using Fe₃O₄ modified by mPDs (mPD = m-phenylenediamine). This material was successfully characterized by transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD), and it was confirmed that Co-BT was adhered to the Fe₃O₄ surface by PmPDs. The dye adsorption performance of magnetic Fe₃O₄@PmPD–[Co-BT] was investigated in detail with selectivity, capacity, thermodynamics and kinetics studies, and with respect to influence factors including the pH value, solvent types, and ionic strength. Notably, the saturated adsorption capacity of magnetic Fe₃O₄@PmPD–[Co-BT] for CR dyes could reach 347.8 mg g⁻¹. The dye removal mechanism was investigated by zeta potential analyses and Fourier transform infrared (FTIR) spectroscopy.