Resumo (PT):
Abstract (EN):
This work is focused on the characterization of heterogeneous Fe-based catalysts supported on activated
carbons (ACs) that are used in elimination of the azo-dye orange II (OII) from an aqueous solution. The
main goal is to clarify the process of OII removal by analyzing textural and chemical surface properties of
the fresh and spent activated carbon and Fenton-like catalysts upon using as adsorbents and/or catalysts.
Textural changes were analyzed based on the corresponding N2 adsorption isotherms and the nature of
the adsorbed products by TG-DTG and TPD. It was found that OII was adsorbed filling the microporosity
without degradation, although interactions between OII molecules and the AC surface groups have been
detected. The total organic carbon (TOC) removal is complete in adsorption experiments. In the catalytic
experiments using different H2O2 concentrations (in the range 6–24 mM) the TOC elimination was never
complete and got worse when increasing the H2O2 load. The OII molecules were partially oxidized and
the adsorption of these products also leads to some blockage of the porosity; higher blockage and higher
TOC removals was noticed after experiments carried out with low H2O2 concentration. The different TOC
removal was related to the interactions of the oxidation products with the carbon surface. When using
the highest concentration of the oxidant (24 mM), the highest biodegradability and the lowest toxicity of
the treated solution were reached, corroborating again the different nature of the oxidation by-products
formed in each case.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Notas:
http://dx.doi.org/10.1016/j.apcatb.2012.09.037
Nº de páginas:
9