Preparation of new materials by ethylene glycol modification and Al(OH)3 coating NZVI to remove sulfides in water

Abstract

In this study, nanoscale zero-valent iron (NZVI) modified by ethylene glycol (EG), and then an aluminum hydroxide (Al(OH)3) film was wound on it to make a new material (EG-NZVI@Al(OH)3), it is used to remove sulfides in water and it has greatly improved the performance of sulfide removal. At different pH values, Al(OH)3 film can effectively improve the adsorption of sulfide by EG-NZVI @Al(OH)3. Al(OH)3 film can also enhance suspension stability and reduce NZVI corrosion in water. The scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) characterization methods were used to prove that the NZVI was successfully modified by EG and coated by Al(OH)3, achieved the role of protecting NZVI from being oxidized during preparation and drying, and enhanced suspension stability, chemical reactivity and longevity. The removal of sulfides in water by NZVI is mainly through the formation of surface complexes, iron mercapto oxide (FeOSH) and the precipitates of iron sulfide (FeS, FeS2, FeSn) adsorbed on the surface of NZVI. Al(OH)3 film is positively charged It will cause electrostatic adsorption and adsorption on sulfur ions. EG-NZVI@Al(OH)3 is used to remove sulfide from 2.5−50 mg/L aqueous solution. It shows the highest adsorption capacity is 175.5 mg/g. And the mechanism of adsorption is speculated.