Green synthesis of nanostructure Schiff base complex based on aromatic polyamide and manganese(III) for elimination of Hg(II) and Cd(II) from solutions

Preparation and characterization of polyimide membranes modified by a task-specific ionic liquid based on Schiff base for CO2/N2 separation

In order to increase CO₂/N₂ selectivity of polyimide (PI) dense membranes, task-specific ionic liquid (TSIL), 1-aminoethyl-3-buthylimidazolium hexafluorophosphate ([NH₂ebim][PF₆]), has been grafted to polymer chains as large side groups by forming the structure of Schiff base for the first time. The modified membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis, thermogravimetric analysis (TGA), X-ray diffraction (XRD), dynamic thermomechanical analysis (DMA), and stress-strain testing. The results showed that TSIL had been successfully linked to PI chains by forming "C=N." The modified membranes had more free volume, which was favorable to the improvement of CO₂ permeability. The reduction of spin degree of freedom means the rigidity increment of polymer chains, which indicated that the selectivity of CO₂/N₂ can be enhanced. As a result, CO₂ permeability of the modified membrane (TSIL-0.8 wt%) was increased from 5.28 to 10.2 Barrer, and CO₂/N₂ selectivity was increased from 21.9 to 92.8 at 30 °C and 0.1 MPa. Meanwhile, the effects of different feed pressures (0.1-0.6 MPa) and different operating temperatures (30-60 °C) on CO₂/N₂ transport properties were also investigated, and it was found that the separation performances of the modified membranes had already exceeded Robeson's upper bound.

Adsorption Processing for the Removal of Toxic Hg(II) from Liquid Effluents: Advances in the 2019 Year

Mercury is a toxic metal, thus, it is an element which has more and more restrictions in its uses, but despite the above, the removal of this metal, from whatever the form in which it is encountered (zero valent metal, inorganic, or organic compounds), and from different sources, is of a widespread interest. In the case of Hg(II), or Hg2+, the investigations about the treatment of Hg(II)-bearing liquid effluents (real or in most cases synthetic solutions) appear not to end, and from the various separation technologies, adsorption is the most popular among researchers. In this topic, and in the 2019 year, more than 100 publications had been devoted to this field: Hg(II)-removal-adsorption. This work examined all of them.