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Author(s): Samuel Queirós
Vânia Morais
Carmen S.D. Rodrigues
Luis M. Madeira
Title: Heterogeneous Fenton's oxidation using Fe/ZSM-5 as catalyst in a continuous stirred tank reactor
Issue Date: 2015
Abstract: This work is the first known report dealing with the heterogeneous Fenton-like process in a continuous stirred tank reactor. A Fe/ZSM-5 zeolite was used as catalyst for degradation of an azo dye (Orange II, OII)-containing solution.A parametric study was carried out to evaluate the effect of the main operating conditions in the basket reactor performance, namely temperature (in the range 1070 °C), pH (1.54.0), feed hydrogen peroxide concentration [H2O2]feed (1.7520.0 mM), contact time W/Q (10200 mg min/mL), residence time tresid (30180 min) and the size of the catalyst particles (0.25 < dp1 < 0.60, 0.60 < dp2 < 0.80 mm and as pellets, dp3 > 5 mm), for a OII feed concentration of 0.1 mM. Under the best operating conditions found (pH = 3.0, T = 70 °C, [H2O2]feed = 6 mM, W/Q = 200 mg min/mL, dp2 and tresid = 90 min), it was achieved 91% of discoloration and 36% of mineralization, at steady-state. Moreover, it was found a removal of 29% in terms of the chemical oxygen demand (COD), being worth noting the improvement in the effluent biodegradability (k oxygen uptake rate increased from 9.3 to 23.2 mgO2/(gVSS h)) and the fact that the final effluent is non-toxic (0.0% of Vibrio fischeri inhibition).The stability of the catalyst performance was checked during five consecutive runs. The crucial factor for the catalyst long-term use is the leaching of iron, which in all runs reached very low levels (e.g. only 0.173 mg/L of iron for the run in the optimized conditions, corresponding to only 0.13% of leaching). The catalyst was characterized by different techniques before and after the reactions (namely SEM/EDS and N2 adsorption); textural and chemical transformations during its use can be considered negligible (except for very acidic conditions of pH = 1.5) favoring the catalytic stability of the Fezeolite.
Subject: Engenharia química, Engenharia do ambiente
Chemical engineering, Environmental engineering
Scientific areas: Ciências da engenharia e tecnologias::Engenharia do ambiente
Engineering and technology::Environmental engineering
Related Information: info:eu-repo/grantAgreement/Autoriadade de Gestão do Programa Operacional Regional do Norte/Programas Integrados de IC&DT/NORTE-07-0124-FEDER-000025/(Bio) Chemical Engineering: Multi-Scale Approaches for Sustainable Environment and Health/LEPAE/CEFT - RL2
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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