Metal–Organic Framework Based on Nickel, L-Tryptophan, and 1,2-Bis(4-Pyridyl)Ethylene, Consolidated on a Track-Etched Membrane

An approach to the functionalization of track-etched membranes (TMs) by a metal–organic framework consisting of nickel, L-tryptophan, and 1,2-bis(4-pyridyl)ethylene (Ni-MOF) was developed. The effect of the TM surface charge on the Ni-MOF self-assembly was studied. It was discovered that the Ni-MOF microstructure was independent of the way in which the TM has been modified. The Ni-MOF self-assembly on chitosan nanofiber–modified TMs appeared to be the most promising approach to the creation of a TM + Ni-MOF composite because it did not deteriorate the performance of the membrane. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), and IR spectroscopy showed that free Ni-MOF (in a powder form) and Ni-MOF in the consolidated material have the same composition and structure. The XPS spectra of Ni-MOF powders after their contact with Cd, Cu, or Cs salt solutions and the kinetic study of Cd, Li, Ag, Zn, Mg, and Li ion adsorption showed that Ni-MOF is a candidate adsorbent of metal ions.