Fenton-like oxidation of phenol with in-situ generated hydrogen peroxide and Pd/Fe-zeolite catalysts

• Published in: Water-Energy Nexus Vol. 4; pp. 95 - 102
• Main Authors: Sable, Shailesh S., Georgi, Anett, Contreras, Sandra, Medina, Francesc
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2021; KeAi Communications Co., Ltd
• Subjects: Adsorption; Advanced Oxidation Processes (AOPs); Degradation; Fe-ZSM5 zeolites; Fenton-like reaction; Palladium; Phenol; Degradation; Phenol; Adsorption; Fe-ZSM5 zeolites; Fenton-like reaction; Palladium; Advanced Oxidation Processes (AOPs)
• ISSN: 2588-9125; 2588-9125
• DOI: 10.1016/j.wen.2021.06.001

•Fe-zeolites were loaded with Pd by impregnation and NaBH4 reduction without affecting Fe speciation.•Addition of low amount of Pd on Fe-ZSM5 improved activity in phenol oxidation by H2O2.•Pd/Fe-ZSM5 allows in-situ generation of hydrogen peroxide from formic acid and oxygen on Pd catalyst.•Pd/Fe-ZSM5 (236) based on high-silica zeolite shows higher efficiency in the formic acid decomposition and phenol removal.•Combined approach of adsorption/oxidation has a positive effect on phenol degradation.
Two types of iron-containing zeolites with different surface hydrophobicity, Fe-ZSM5 (SiO2/Al2O3 = 26) and Fe-ZSM5 (SiO2/Al2O3 = 236) were studied as adsorbents and catalysts for oxidation of phenol by means of a Fenton-like process at ambient conditions and nearly neutral pH, with and without in-situ generation of H2O2. Adsorption of phenol is more favorable on high silica Fe-ZSM5 (236) zeolite due to its higher surface hydrophobicity. Palladium (Pd) immobilization on Fe-ZSM5 zeolites has a positive impact on phenol degradation with a synergistic role of Pd and Fe (II)/(III) for activation of H2O2. The best result for phenol conversion and mineralization was observed over both hydrophilic and hydrophobic 0.1 wt.% Pd/Fe-ZSM5 with commercial H2O2 achieving ≥ 90% conversion of phenol (100 mg/L) in 4 h and 60–63% mineralization in 6 h with 5 g/L catalyst and 5 g/L H2O2. In addition, Pd/Fe-ZSM5 can be used for in-situ formation of H2O2 using formic acid as H-source and externally supplied oxygen. The combination of these processes provided by this adsorbent/catalyst material is exploitable for on-site oxidative regeneration of zeolite adsorbents. This study shows that Fe-containing zeolites are promising catalysts for a combined approach of adsorption/oxidative degradation of phenol by commercial or in-situ produced H2O2.