Xrd 700

The porous sample nature was investigated by N₂ adsorption-desorption technique and specific surface area was calculated using Brunauer – Emmett-Teller method (BET). Morphology was evaluated by scanning electron microscopy with field emission (SEM-FEG) using FEI Inspect F50 in the secondary electron mode (SE). Chemical composition was evaluated by energy dispersion X-ray spectrometry (EDS). For this purpose, samples were covered with a thin layer of gold. X-ray diffraction pattern (XRD) was recorded on Shimadzu XRD-700 equipment using Cu Kα radiation, voltage of 40 kV, 30 mA (1.5418 Å) ranging from 2 to 70° with scanning speed of 4°/min. Samples thermal stability and the immobilized ionic liquid actual content were evaluated by TGA/DTG (TA Instruments SDT-Q600), under nitrogen atmosphere within the range from 25 to 800 °C and heating rate of 20 °C/min. All analyses were conducted in triplicate. The IL loading in silica support (denoted as IL%) was calculated from the TGA curve using the following Eq. (2): $IL\left(\%\right)=\frac{W_{150}-W_{800}}{W_{150}}\times 100$ Where, W₁₅₀ and W₈₀₀ are sample weight (g) at 150 °C and 800 °C, respectively.

The morphology and structure of samples were investigated by high resolution transmission electron microscopy (TEM, JEOL-3010) and scanning electron microscopy (SEM, SU-8000). Small angle X-ray diffraction (SAXRD) patterns were obtained by using an X-ray diffractometer (XRD Shimadzu Limited XRD-700) with a Cu Kα radiation source (λ ≈ 1.54 Å) in the range of 0.5–5.5°. The elemental analysis was performed on an X-ray photoelectron spectroscopy instrument (XPS AXIS Ultra Kratos Analytical Ltd). The BET specific surface area (S_BET) and Barrett–Joyner–Halenda (BJH) pore size distribution were measured on a NOVA4200e surface area analyzer by using the N₂ gas adsorption/desorption isotherm. Fourier transform infrared (FTIR) spectra were recorded by a FTIR-8400S spectrometer. The samples and KBr were pressed to form thin plates (the mass of KBr and the as-prepared sample was about 200 mg and 2 mg, respectively) for obtaining the FTIR spectra. Thermogravimetric analysis (TGA) was carried out using a F2009 TG analyzer in the range of 25–900 °C at a heating rate of 10 °C min⁻¹ under N₂ flow. The zeta potential of the samples was measured by using a Zetasizer ZEN 3500 potentiometer in the pH range of 7–13.