One‑pot synthesis of S‑doped Fe2O3/ C magnetic nanocomposite as an adsorbent for anionic dye removal: equilibrium and kinetic studies

Novel S-doped Fe2O3/ C nanocomposite was synthesized via a one-pot hydrothermal method and was used for the first time as an efficient adsorbent for Congo red dye (CR) removal from water solution. The obtained catalyst was characterized by various methods including Fourier transform infrared spectroscopy, energy dispersive X-ray spectrometry, vibration sample magnetometry, X-ray diffraction and field emission scanning electron microscopy. To improve the adsorption performance, some important parameters affecting dye removal were optimized such as adsorbent dosage, contact time, solution pH, initial dye concentration and ionic strength. At the optimum conditions, the maximum capacity of adsorption for this nanocomposite was 270.2 mg g−1, which is better than other magnetic adsorbents for CR removal. The results of adsorption isotherm were matched with Langmuir model. Kinetic tests show that adsorption experimental data were best fitted by pseudo-first-order model.