Enhancing H2O2 utilization efficiency for catalytic wet peroxide oxidation through the doping of La in the Fe-ZSM-5 Catalyst

Abstract

Iron-supported zeolite has shown great potential as an e cient catalyst for degrading organic pollutants with high concentrations in the catalytic wet peroxide oxidation (CWPO) process under mild conditions. Here 0.4 wt.% La was added in the 1.0 wt.% Fe-ZSM-5 by two-step impregnation method for an enhanced H 2 O 2 utilization e ciency. For a systematical comparison, the CWPO process under 55°C, where m-cresol with a high concentration of 1000 mg/L as a substrate, was studied over Fe-ZSM-5 and Fe-La-ZSM-5 catalysts. Compared with Fe-ZSM-5, Fe-La-ZSM-5 showed 15% higher H 2 O 2 utilization e ciency with comparable TOC removal at around 40%, meanwhile with a 15% reduced metal leaching. Transmission electron microscopy (TEM) with EDS mapping, surface acidity analysis by Fourier Transform InfraRed (FT-IR) and NH 3 -Temperature Programmed Desorption (NH 3 -TPD), redox property analysis by Raman spectroscopy and H 2 -Temperature Programmed Reduction (H 2 -TPR) of both catalysts revealed, a altered surface acidity, a more uniform and evenly dispersed surface Fe species with a promoted reducibility, which effectively prevented the ineffective decomposition of H 2 O 2 , enhanced the H 2 O 2 utilization e ciency, and increased the catalyst stability. Also, more than 90% conversion of 1000 mg/L m-cresol for more than 10 consecutive test days under 55°C without pH adjustment showed a promising possibility of the Fe-La-ZSM-5 for a practical wastewater treatment process.