Removal efficiency and mechanism of refractory organic matter from landfill leachate MBR effluent by the MoS2-enhanced Fe0/H2O2 system

In this study, molybdenum disulfide (MoS 2 ) was used to enhance a zero-valent iron/hydrogen peroxide (Fe 0 /H 2 O 2 ) Fenton-like system, which was able to remove refractory organic matter from the effluent produced during the treatment of landfill leachate by a membrane bioreactor (MBR). The MoS 2 /Fe 0 /H 2 O 2 system could efficiently remove refractory organic matter (i.e., fulvic acid-like substances and humic-like substances) from the MBR effluent and also exhibited a strong synergistic effect. Under the conditions of initial pH = 3, H 2 O 2 = 40 mmol/L, Fe 0 = 0.4 g/L, MoS 2 = 0.1 g/L, and t = 30 min, compared with a Fe 0 /H 2 O 2 system, the absorbance UV 254 , chroma (CN), and total organic carbon (TOC) removal rates in MBR effluent treated with MoS 2 /Fe 0 /H 2 O 2 increased to 48.68%, 63.85%, and 35.85%, respectively. Through the identification of reactive oxygen species (ROS), the hydroxyl radical (HO • ) concentration and an analysis of the effective utilization rate of H 2 O 2 , as well as an analysis of the morphology of the material, the distribution of Fe compounds, valence changes, and the Fe ion concentration , it was proven that MoS 2 promoted the cycling of Fe 3+ /Fe 2+ in the Fe 0 /H 2 O 2 process. The addition of MoS 2 promoted the Fe 3+ /Fe 2+ cycling reaction through the exposed Mo 4+ active center, significantly promoting the decomposition of H 2 O 2 and the formation of HO • . The MoS 2 /Fe 0 /H 2 O 2 system was able to remove a wide range of aromatic organics, indicating the wide applicability of the system. This study developed a new method for the efficient removal of refractory organic matter from landfill leachate.