%0 Journal Article %T Reduction Kinetics of Nitroaromatic Compounds by Titanium Substituted Magnetite %+ Institut des Sciences Chimiques de Rennes (ISCR) %+ Géosciences Rennes (GR) %A Marsac, Remi %A Pasturel, Mathieu %A Hanna, Khalil %Z ADEME "Agence de l'Environnement et de la Maitrise de l'Energie" [1472C0030] %< avec comité de lecture %@ 1932-7447 %J Journal of Physical Chemistry C %I American Chemical Society %V 121 %N 21 %P 11399-11406 %8 2017-06-01 %D 2017 %R 10.1021/acs.jpcc.7b01920 %Z Chemical SciencesJournal articles %X Although there is a growing interest in environmentally friendly catalytic processes based on magnetic solids, the reactivity of titanomagnetite (Fe-3,TixO4) having a "tunable" solid-state Fe(II)/Fe(III) ratio for reductive transformation of nitroaromatic compounds has been never investigated. This study, for the first time, comprehensively examines the reduction kinetics of nitroaromatic compounds by titanium-substituted magnetite and compares with that of Fe(II) amended-unsubstituted magnetite at equal amounts of total Fe(ll). First, we demonstrated that Ti substitution in magnetite increased considerably the ability of magnetite to reduce 4-nitrophenol (4-NP) as well as nitrobenzene (NB) in a surface-mediated electron transfer pathway. However, Fe(II) amendment of magnetite (x = 0) to have an equivalent amount of total Fe(II) as in the corresponding titanomagnetite (0.25 <= x <= 0.75) resulted in higher reduction rate constants for both substrates (4-NP and NB). Initial k(obs) was shown to increase exponentially with (Fe(II)/Fe(III))(bound) in magnetite, while for titanomagnetites a logarithmic dependence of k(obs) with increasing (Fe(II)/Fe(III))(bound) was observed. Only the early-stage kinetic behavior differs between titanomagnetite and Fe(II)-amended magnetite at the same total Fe(II) amount. Changes in Fe2+/Fe3+ electron delocalization properties or electron hopping, presumably due to the mixing of Fe' and Ti4+ on the octahedral sites, may affect the surface-mediated electron transfer between the solid-state and the redox-sensitive species in solution. These bulk-controlled mechanisms drive the electron transfer process both within the solid phase and across the solid/ water interface, thereby altering the regeneration of active sites and ongoing reduction reaction on the magnetite surface. %G English %2 https://univ-rennes.hal.science/hal-01559202/document %2 https://univ-rennes.hal.science/hal-01559202/file/Marsac%20et%20al.%20-%202017%20-%20Reduction%20Kinetics%20of%20Nitroaromatic%20Compounds%20by%20T.pdf %L hal-01559202 %U https://univ-rennes.hal.science/hal-01559202 %~ INSU %~ UNIV-RENNES1 %~ UR2-HB %~ CNRS %~ INSA-RENNES %~ ENSC-RENNES %~ GR %~ OSUR %~ ISCR %~ SCR-CIP %~ ISCR-CSM %~ STATS-UR1 %~ UR1-SPM %~ INC-CNRS %~ UR1-UFR-SPM %~ UR1-HAL %~ UR1-SDLM %~ UNIV-RENNES2 %~ TEST-UNIV-RENNES %~ TEST-UR-CSS %~ UNIV-RENNES %~ GR-NBG %~ INSA-GROUPE %~ INRAE %~ TEST-HALCNRS %~ UR1-MMS %~ UR1-ENV %~ GR-NANO %~ TEST2-HALCNRS