Synthesis of coal fly ash zeolite for the catalytic wet peroxide oxidation of Orange II
Fly ash, a coal combustion residue produced by Termotasajero in Colombia, has been hydrothermally treated after an alkaline fusion to produce zeolite without addition of silicon or aluminum. The starting material was thoroughly mixed with NaOH, in a 1:1.2 mass ratio, to obtain a homogeneous mixture that was heated to 100 °C during different times (6, 8, and 10 h) and three zeolite samples were produced. The samples were characterized by XRD, SEM, XRF, Mössbauer spectroscopy, and N2 physisorption. According to characterization results (high surface area and appropriate morphological properties including crystallinity) and synthesis time, zeolitic catalyst synthesized with 8 h of hydrothermal treatment was selected to perform further analysis. This sample consisted of a mixture of zeolite X and zeolite A of high surface area (301 m2 g−1) and a Fe content of 6% wt/wt. The zeolite was used as a catalyst for the Fenton oxidation of Orange II. Experiments were performed in a laboratory batch reactor at 70 °C and constant pH = 3, using different concentrations of H2O2. When the stoichiometric amount of H2O2 was used, good mineralization (XTOC = 45%), complete discoloration, and oxidant consumption were obtained after 240 min of reaction. The sample retained activity after 16 h of usage. The presence of Fe in the reaction media was always detected and a homogeneous Fenton mechanism induced by surface-leached iron is suggested.
KeywordsFly ash Zeolite Geo-catalyst Fenton reaction Orange II Mineralization Discoloration
The Argentinian authors want to express their gratitude to Ms. Carmen Rodriguez for the execution of experiments.
This study received financial support from CONICET (Argentina) and AUIP (Spain).
- Brand RA (1991) Normos programs (SITE-DIST). Duisburg UniversityGoogle Scholar
- Cornell RM, Schwertmann U (2000) The iron oxides, structure, reactions, occurrence and uses, 2nd edn. VCH, WeinheimGoogle Scholar
- Duarte F, Maldonado-Hódar FJ, Madeira LM (2011) Influence of the characteristics of carbon materials on their behaviour as heterogeneous Fenton catalysts for the elimination of the azo dye Orange II from aqueous solutions. Appl Catal B Environ 103(1–2):109–115. https://doi.org/10.1016/j.apcatb.2011.01.016 CrossRefGoogle Scholar
- Guerra Núñez MM (2016) Photocatalytic degradation of Orange II dye using zeolite x-Fe catalyst synthesized from coal fly ash (Master Thesis). In: Bogotá D.C.: Universidad Nacional de Colombia. Bogotá, ColombiaGoogle Scholar
- Rache ML, García AR, Zea HR, Silva AMT, Madeira LM, Ramírez JH (2014) Azo-dye orange II degradation by the heterogeneous Fenton-like process using a zeolite Y-Fe catalyst- kinetics with a model based on the Fermi's equation. App Catal B: Environ 146:192–200. https://doi.org/10.1016/j.apcatb.2013.04.028 CrossRefGoogle Scholar
- Ramírez JH, Costa CA, Madeira LM, Mata G, Vicente MA, Rojas-Cervantes ML, López-Peinado AJ, Martín-Aranda RM (2007b) Fenton-like oxidation of Orange II solutions using heterogeneous catalysts based on saponite clay. Appl Catal B Environ 71(1–2):44–56. https://doi.org/10.1016/j.apcatb.2006.08.012 CrossRefGoogle Scholar
- Vandenberghe RE (1991) Mössbauer spectroscopy and applications in geology. Apostilha International Training Centre for Post-Graduate Soil ScientistsGoogle Scholar
- Ventura Camargo BC, Marin Morales MA (2013) Azo dyes: characterization and toxicity- a review. Textiles Light Ind Technol 2:85–103Google Scholar