FTIR-ATR spectra of the synthesized MIL-101 (Fe), MIL-GO composite fillers and membranes were obtained by using Nicolet iS10 (Thermal Scientific, Waltham, USA) spectrometer in the range of 400–4000 cm−1.
XRD analyses for the synthesized MIL-101 (Fe), and MIL-GO composite fillers were conducted by utilizing Philips X′′Pert (Malvern Panalytical, Malvern, UK). The transmission mode and 2θ range of 5–80° were applied.
The nitrogen adsorption/desorption measurements for the synthesized MIL-101 (Fe), and MIL-GO composite fillers were conducted at −195.7 °C via Gemini VI (Micromeritics Instrument Corp., Norcross, GA, USA). All samples were degassed for 6 h at 110 °C before the measurements.
Thermal properties of the synthesized MIL-101 (Fe), MIL-GO composite fillers and membranes were analyzed by using a Jupiter STA 449 F5 (Netzsch, Germany) thermogravimetric analyzer. TGA measurements were conducted from 25 °C to 950 °C under the nitrogen atmosphere.