ZIF nanoparticles and membrane characterizations
Powder X-ray diffraction (PXRD) and Wide-angle X-ray diffraction (WXRD) patterns were determined for ZIFs nanoparticles and membranes by using an X-ray diffractometer (Ultima IV, Japan) with Cu-Kα X-ray radiation (λ =1.54056 Å) from 5 to 40º at the rate of 5o min-1, respectively. For testing the textural properties of synthesized ZIFs materials surface area analyzer (BELSORP Japan) was used by N2 adsorption and desorption at 77 K. The surface areas of ZIF-8 and Ni-ZIF-8 were calculated by the use of standard Brunauer-Emmett-Teller (BET) equation. Before measuring the surface area, the samples were pre-dried at 150ºC for 6 hrs under a continuous flow of N2. Morphologies and Energy disperse X-ray spectroscopy (EDXS) of the ZIFs particles, and MMMs were observed through a field-emission scanning electron microscope (FE-SEM, JSM-7500F, JEOL, Japan), which was operated at 5 kV. FTIR spectrum was plotted by using ATR-FTIR (Thermo Nicolet IS10, USA) by setting the range of 4000–500 cm-1 with a resolution of 4 cm-1. Thermal stabilities analysis of the nanoparticles and MMMs were analyzed by thermogravimetric analysis (TGA-60 Shimadzu Japan) in the range of 30 to 800ºC with a ramp rate of 5ºC min-1, under the continuous flow of nitrogen. The same instrument (TGA-60 Shimadzu Japan) was used for differential scanning calorimetry (DSC) analysis of MMMs.