Activation of H2O2 by carbonaceous iron sludge-derived catalyst for methylene blue wastewater treatment

Abstract

Resource utilization of waste iron sludge from wastewater treatment plants can be achieved by leveraging iron sludge-based catalysts to construct Fenton-like systems. Notably，the pyrolysis temperature modulates the composition of metal and non-metal sites on the catalyst surface，thus affecting the activation of hydrogen peroxide（H2O2）. The catalysts prepared at different pyrolysis temperatures（400-700 ℃） were analyzed in terms of morphology，composition，structure and activity. It was found that the degradation efficiency of methylene blue（MB） could reach 92.0% within 100 min with the activation of H2O2 by the catalyst obtained at 700 °C. Additionally，the specific surface area and C content of the catalyst increased as the pyrolysis temperature increased from 400 ℃ to 700 ℃. The mechanistic investigation revealed that Fe0，C̿ C/C—C and C̿ O active sites on the catalyst surface were critical for the activation of H2O2，which facilitated MB degradation. Moreover，hydroxyl radicals（·OH） and singlet oxygen（1O2） were the dominant active species in the iron sludge-derived catalyst/H2O2 system，with superoxide radicals（O2·-） playing a minor role.

Keywords

• waste iron sludge
• fenton-like
• dye wastewater