## 2 Experimental
### Characterizations  
Powder X-ray diffraction (XRD) patterns were estimated using a DBMAXB Rigaku diffractometer (Bruker, Karlsruhe, Germany) with Cu\({}_{\text{K}\alpha}\) radiation at 40 kV and 40 mA. The intensity data was collected over a 20 value from 20\({}^{\circ}\) to 70\({}^{\circ}\). The patterns were indexed using Joint Committee of Powder Diffraction Standard (JCPDS) data base files. Vibrational modes were obtained using Raman spectroscopy with a LabRam spectrometer (HR Horiba Scientific), which is equipped with a charge coupled device. The detector was cooled using liquid nitrogen at \(-\)196 \({}^{\circ}\)C. An excitation source line of 532 nm was used with the laser power of 20 mW. The spectral resolution was 4 cm\({}^{-1}\) with the use of an objective lens of 100 times. The spectra were recorded in the 100-200 cm\({}^{-1}\) range. Fourier transform infrared spectroscopy (FTIR) measurements were carried out in the 500-4000 cm\({}^{-1}\) range in the Spectrum 100 Perkin Elmer equipment (Bruker, Rheinstetten, Germany). About 10 mg of the samples were mixed with 200 mg of vacuum dried KBr and subjected to external pressure of 8 tons on each sample, in order to create an almost transparent pill to perform FTIR measurements. The morphology was observed using a FEI, Quanta 200 FEG electron microscope (FEI Quanta, Hillsboro, OR, USA) in scanning electron microscopy (SEM) mode. The unit is equipped with Energy Dispersive Spectroscopy (EDS) system and all samples were gold sputtered to achieve a good contrast. Textural properties of the solids were evaluated through nitrogen adsorption-desorption isotherms at liquid nitrogen temperature in an ASAP 2420 apparatus from Micromeritics (Micrometrics, Norcross, GA, USA). Previously, the samples were heated at 150 \({}^{\circ}\)C and outgassed at this temperature for 8 h. Specific surface areas were calculated by using the Brunauer Emmett and Teller (BET) equation and the pore size distribution were obtained by the Barrett Joyner Halenda (BJH) model. The chemical states of the elements were determined by X-ray photoelectron spectroscopy (XPS). The XPS spectra were recorded with a Physical Electronics VersaProbe II Scanning XPS Microprobe (Minneapolis, MN, USA) with scanning monochromatic X-ray Al K\(\alpha\) radiation (100 m area analyzed, 52.8 W, 15 kV, 1486.6 eV), and a charge neutralizer. The pressure in analysis chamber was maintained lower than \(2.0\times 10^{-6}\) Pa. High-resolution spectra were recorded at a given take-off angle of 45\({}^{\circ}\) by a multi-channel hemispherical electron analyser operating in the constant pass energy mode at 29.35 eV. The energy scale was calibrated using Cu 2\(p_{3/2}\), Ag 3\(d_{5/2}\), and Au 4\(f_{7/2}\) photoelectron lines at 932.7, 368.2 and 83.95 eV, respectively. Spectra were charge referenced with the C 1\(s\) of adventitious carbon at 284.8 eV. Zeta potential analyses were carried out in a Zetasizer Nano ZS instrument (Malvern, GBR, Cambridge, UK) equipment. About 0.03 g of the samples in 30 mL of ultrapure water was used. The solids were placed in vials and the pH was 6.8. Samples were taken from the supernatants to perform the zeta potential analyses. Electron paramagnetic resonance (EPR) measurements were carried out to detect the local environment of iron atoms and valence states. The EPR measurements were performed using a [PERSON] spectrometer (Bruker, Rheinstetten, Germany) with X-band microwave frequencies at 9.5 GHz with sweep integrated for X-band spectra to determine the \(g\) factor. Before the measurements, all samples were flushed with helium at room temperature. Magnetic properties of the composites were evaluated through the magnetic hysteresis loops using Lakeshore vibrating sample magnetometer (VSM). The analyses were conducted in a Mini 5T Cryogenic equipment. Previously, the VSM was calibrated using YIG spheres to obtain the magnetization curves at room temperature. Structural and magnetic features of the solids were investigated by \({}^{57}\)Fe Mossbauer spectroscopy.