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

Abstract

Abstract Iron-supported zeolite has shown great potential as an efficient 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 H2O2 utilization efficiency. 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 H2O2 utilization efficiency 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 NH3-Temperature Programmed Desorption (NH3-TPD), redox property analysis by Raman spectroscopy and H2-Temperature Programmed Reduction (H2-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 H2O2, enhanced the H2O2 utilization efficiency, 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.