Performance, kinetics and mechanism of Fe(II)EDTA regeneration with surface-fluorinated anatase TiO2 with exposed (001) facets

Abstract

Fe(II)EDTA regeneration mainly referring to Fe(III)EDTA and Fe(Ⅱ)EDTA-NO reduction has a very remarkable significance for NO removal using Fe(II)EDTA solution. Here, surface-fluorinated anatase TiO2 nanosheets with exposed (001) facets (F-TiO2) was prepared and firstly served for Fe(II)EDTA regeneration with ultraviolet light. The performance and kinetics of Fe(II)EDTA regeneration had been investigated under different F-TiO2 dose, varied pH, and diverse temperatures, in which Fe(III)EDTA and Fe(II)EDTA-NO reduction rate raised and then decreased under pH increasing or F-TiO2 dose rise. High temperature was conducive to Fe(II)EDTA regeneration. Fe(III)EDTA and Fe(II)EDTA-NO reduction presented first order reaction. Moreover, the F-TiO2 still maintained an excellent reduction efficiency after three recycle. Mechanism study showed that excellent Fe(II)EDTA regeneration ability could be partly explained by the high separation efficiency of photogenerated electrons and holes of F-TiO2. The bonded NO was converted into NH4+, N2, and N2O. Finally, compared with other Fe(II)EDTA regeneration systems, photocatalytic regeneration is a more suitable alternative in Fe(II)EDTA complexation denitrification technology.