Heterogeneous photocatalytic reduction of Fe(VI) in UV-irradiated titania suspensions: effect of ammonia

Authors: Sharma, Virender K.; Chenay, Benoit V.N.

Source: Journal of Applied Electrochemistry, Volume 35, Numbers 7-8, July 2005 , pp. 775-781(7)

Publisher: Springer

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Abstract:

Results of the heterogeneous photocatalytic reduction of Fe(VI) in UV-irradiated TiO₂ suspensions in the presence of ammonia are presented. The initial rate of Fe(VI) reduction, R, may be expressed as R = k _Fe(VI)[Fe(VI)]^1.25 where k _Fe(VI) = a[Ammonia]+b), a = 6.0 × 10³ μ<Emphasis Type="SmallCaps">m</Emphasis> ^0.25 s and b = 4.1 × 10⁶ μ<Emphasis Type="SmallCaps">m</Emphasis> ^−1.25s⁻¹. The rate constant, k _Fe(VI), increases with the ammonia concentration. The photocatalytic oxidation of ammonia is enhanced in the presence of Fe(VI). A mechanism involving Fe(V) as a reactive intermediate is presented which explains the faster photocatalytic oxidation of ammonia in the presence of Fe(VI).

Keywords: ferrate (VI); ferrate(V); TiO2; mechanism; remediation

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s10800-005-5169-8

Affiliations: 1: Email: vsharma@fit.edu

Publication date: 2005-07-01