Resumo (PT):
Abstract (EN):
This work deals with the treatment of textile effluents by the heterogeneous Fenton-like process in a
fixed-bed reactor filled with a catalyst based on activated carbon impregnated with iron (AC/Fe). In a preliminary stage, the dye Alcian Blue-tetrakis (methylpyridinium) was used as model compound. The catalyst is essentially microporous, with large micropores and some mesopores, and is able to adsorb the
dye, although its adsorption capacity is limited as a consequence of the large size of the dye molecule.
The stability of the catalyst was checked with five consecutive runs, without significant loss of activity
(less than 5%). Then, the effect of the main operating conditions was analyzed, and the H2O2 dose, pH
and temperature were optimized; the best conditions found using CAB,feed = 0.01 mM and a contact time
of 3.3 g min ml1 were: CH2O2,feed = 30.0 mM, pH = 2.5 and T = 50 C, with which it was achieved 93.2% of
discoloration and 54.1% of total organic carbon (TOC) removal in the steady-state. It was verified that pH
had a preponderant effect on the oxidation performance. Finally, the selected catalytic system was
applied to the treatment of a real textile effluent used in the cotton dyeing. It was achieved almost total
discoloration (96.7%) and a strong abatement of the TOC – 73.6%, as well as of the chemical oxygen
demand (COD) – 66.3%, and biochemical oxygen demand (BOD5) – 72.5%. The iron leached reached very
low levels in every run, which is a crucial factor for the catalyst long-term use
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
8