Oxidation of the thiosulfate ion by some iron(III) complexes with phenolate - amide-amine coordination: A comparative kinetic study

Preparation and characterization of γ-Fe2O3 nanoparticles and investigation of its adsorption performance for sulfide, sulfite and thiosulfate from aqueous solutions using ultrasonic assisted method: Modeling and optimization

Maghemite nanoparticles, as an adsorbent, was used for the removal of sulfur species including sulfide, sulfite and thiosulfate from waste water samples by ultrasonic-assisted adsorption method. The characterization of the prepared nanoparticles was carried out by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and BET technique. The nanoparticles well dispersed in the water. The adsorbent was easily separated magnetically from the solution after loading with adsorbate. According to central composite design, the best experimental conditions including initial pH, the dosage of adsorbent and sonication time were obtained for sulfide, sulfite and thiosulfate. After optimization of the parameters, the removal of analytes in these conditions lead to the highest analytes removal efficiency (above 98%). The adsorption capacity was evaluated using different adsorption isotherm models. The maximum predicted adsorption capacities for sulfide, sulfite and thiosulfate were obtained as 148.5, 122.5 and 119.6mgg^-1, respectively. Then, desorption process of the adsorbed thiosulfate was also investigated using sodium hydroxide solution as the solvent and the other conditions affect to desorption were optimized.