Reduction of bromate from water by zero-valent iron immobilized on functional polypropylene fiber

• The mZVI immobilized in acrylic acid functionalized PP fiber is prepared.
• The mZVI/PP-g-AA shows a preferable removal efficiency towards bromate.
• The COOH/COO− groups shows buffering ability in close proximity of the mZVI.
• The inhibitory effects by common anions and humic acid are slight.

The highly reactive micro-sized zero-valent iron (mZVI) immobilized in acrylic acid (AA) functionalized polypropylene fiber (PP-g-AA) was successfully prepared, and used for the bromate removal from solution. The PP-g-AA was used as a novel carrier for its high strength and continuous supports with chelating functional groups. The mZVI was immobilized firmly on PP-g-AA via complexation and liquid phase reduction, which prevented the aggregation of mZVI and release of Fe ions. The mZVI/PP-g-AA was characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and emission scanning electron microscope (SEM) and Brunauer–Emmett–Teller (BET) surface area analyzer. Due to the coordination with carboxyl groups, the mZVI presented excellent distribution and high activity for reduction of bromate. Meanwhile, the bromate removal efficiency affected by initial bromate concentration, pH, common anions and humic acid (HA) were respectively evaluated. The effects of pH value on bromate reduction was slight. It was related to the buffering performance of the COOH/COO− groups around the areas where the reduction took place. The inhibitory effects of common anions and HA were slight and negligible. In this study, the concentration of Fe2+/3+ in solution was low (<19.0 μg/L) and kept constant during reduction process. On account of the coordination of carboxyl groups on the functional PP fibers, Fe2+/3+ could be remained in the carrier and not be released into solution.