Orientador(es)
Resumo(s)
Here we report preliminary catalytic wet peroxide oxidation (CWPO) experiments performed in the presence of
an alternating current (AC) magnetic field. One ferromagnetic graphitic nanocomposite – composed by a cobalt
ferrite core and a graphitic shell (CoFe2O4/MGNC), was employed in the process, here named magnetically
activated catalytic wet peroxide oxidation (MA-CWPO). An aqueous solution containing 5.0 g L−1 of 4-nitrophenol
(4-NP) to simulate a high strength polluted stream was used as model system. The experiments were
performed at room temperature and atmospheric pressure, with stoichiometric amount of hydrogen peroxide
(H2O2), pH=3 and CoFe2O4/MGNC catalyst load=5.0 g L−1 (corresponding to a 4-NP/CoFe2O4 mass ratio of
6.9, as CoFe2O4 accounts for 14.4 wt% of CoFe2O4/MGNC). It was shown that the performance of CWPO is
enhanced upon application of an AC magnetic field (frequency of 533.9 kHz and magnitude of 240 G). As a
result, high 4-NP mineralization was obtained by MA-CWPO (as reflected by a total organic carbon abatement of
79% after 4 h of reaction, instead of 39% in the absence of a magnetic field). This positive effect was ascribed to
the localised increase of CoFe2O4/MGNC surface temperature resulting from heat release upon exposure of the nanoparticulated catalyst to an AC magnetic field, which accelerates the catalytic decomposition of H2O2 via
hydroxyl radicals (HO%) formation.
Descrição
Palavras-chave
Core-shell nanocomposites CWPO Ferromagnetic composites Heterogeneous Fenton process Magnetic hyperthermia
Contexto Educativo
Citação
Ribeiro, Rui; Gallo, Juan; Bañobre-López, Manuel; Silva, Adrián; Faria, Joaquim L.; Gomes, Helder T. (2018). Enhanced performance of cobalt ferrite encapsulated in graphitic shell by means of AC magnetically activated catalytic wet peroxide oxidation of 4-nitrophenol. Chemical Engineering Journal. ISSN 1385-8947. p. 1-7