Heterogeneous Fenton’s oxidation using Fe/ZSM-5 as catalyst in a continuous stirred tank reactor

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Samuel Queirós (Author) FEUP; Vânia Morais (Author) FEUP; Carmen S. D. Rodrigues (Author) FEUP; Luís M. Madeira (Author) FEUP; F. J. Maldonado-Hódar (Author) Other

Journal

Title: Separation and Purification Technology

Vol. 141

Pages: 235-245

ISSN: 1383-5866

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 23 Citations

ISI Web of Science

Scopus - 39 Citations

Scientific classification

FOS: Engineering and technology > Environmental engineering

CORDIS: Technological sciences > Engineering > Chemical engineering

Associated Projects

LEPAE/CEFT - RL2 - (Bio) Chemical Engineering: Multi-Scale Approaches for Sustainable Environment and Health

Other information

Authenticus ID: P-00A-5XN

DOI: 10.1016/j.seppur.2014.11.046

Abstract (EN): 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 10–70 C), pH (1.5–4.0), feed hydrogen peroxide concentration – [H2O2]feed (1.75–20.0 mM), contact time – W/Q (10–200 mg min/mL), residence time – tresid (30–180 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 (k0 – 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 Fe-zeolite.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11