Water-stable metal organic framework-199@polyaniline with high-performance removal of copper II.

Metal organic frameworks (MOFs)-based adsorbents for copper ion (Cu2+) generally have the disadvantages of instability in water, low adsorption capacity, and selectivity. Aimed at such problems, we fabricated MOF-199 coated with polyaniline (MOF-199@PANI, core@shell) composite for specific adsorption of Cu2+ in water efficiently. Combined with the characterization by SEM, XRD, and FT-IR, the comprehensively excellent performance probably derived from porous structures of MOF-199, as well as the complexation between Cu2+ and the N atoms of imine moieties in PANI. In addition, the coating process by PANI perfectly protected the MOF skeleton. The isothermal data fitted well to Langmuir isotherm model, of which the calculated adsorption capacity reached 7831.34 mg/g. It was one or two orders of magnitude higher than some other new absorbent for Cu2+ including some carbon-based or organic adsorbents. On the basis of the optimization including pH value, temperature, and ratio of raw materials, the fabricated composite has realized the removal of the spiked Cu2+ in actual fresh water and industrial wastewater samples.