Performance and mechanism of ferric tannate in nitrogen removal from wastewater

Ferric tannate (FT) has capacities on simultaneous adsorption of NH₄ ⁺-N and NO₂ ^--N. So far, no study has been reported on the mechanism of FT in the removal of NH⁺-N and NO₂ ^--N. In this work, FT was prepared for nitrogen removal, and the potential of FT in treating NH⁺-N and NO₂ ^--N from aqueous solution was investigated. The influence parameters e.g. substrate concentration and FT dosage on removing nitrogen from aqueous solution were optimized. The results showed that more N₂ generated when FT was added to the oxidation-reduction reaction between NH₄ ⁺-N and NO₂ ^--N. The concentration of NO₂ ^--N was higher than that of NH₄ ⁺-N would be conductive for the N² generation when adding FT. The Fourier Transform Infrared (FTIR) Spectrometer results showed that the structure of the FT (Fe-O) changed in the redox between NH₄ ⁺-N and NO₂ ^--N. The X-ray photoelectron spectroscopy (XPS) results showed that Fe³⁺ and Fe²⁺ coexisted in FT. (paper)