Preservation of Fe complexes into layered double hydroxides improves the efficiency and the chemical stability of Fe complexes used as heterogeneous photo-Fenton catalysts

Fe complexes ([Fe(Ox)(3)](3-) and [Fe(Cit)(2)](3-)) have been heterogenized through preservation into MgAllayered double hydroxides (LDHs). The SEM images and N2 adsorption-desorption isotherm showed that the obtained products were mesoporous materials and the specific surface area of LDHs/Fe-complex composites were obviously greater than pristine LDHs, which is beneficial for the adsorption of organic pollutants. Measurement of adsorptive and heterogeneous photo-Fenton degradation of methylene blue (MB) suggested that the LDHs/Fe-complex composites had an excellent adsorption capacity at different pHs and the adsorption isotherm modeled well with the Langmuir equation. The enhancement of adsorption capacity may be attributed to the external hydroxyl groups of LDHs. MB was enriched on the surface of LDHs/Fe-complex composites, which favors MB degradation in situ. The obtained composites displayed an high photocatalytic activity in a pH range from 4.0 to 6.0 with dissolved Fe cation at a low concentration. Therefore, Fe complexes intercalated into LDHs can be an effective heterogeneous Fenton catalyst for oxidation of organic pollutants in a relatively wide pH range. (C) 2013 Elsevier B.V. All rights reserved.