Preparation of natural manganese sand based catalytic ceramic membrane for removing tetracycline from water: The performance and mechanism

The preparation of catalytic ceramic membranes with low cost and high activity to effectively remove antibiotics from water, is still a challenging work. In this paper, natural manganese sand (NMS) was used as an alternative material for synthesized metal oxide catalysts to prepare a novel catalytic ceramic membrane (NMS-CCM) for activating peroxymonosulfate (PMS) to degrade tetracycline (TC) from water. The preparation method, structural characteristics, catalytic performance, and mechanism were investigated. It is found that the NMS-CCM sintered at 1100 °C for 2 h and with the NMS mass ratio of 46 % exhibited appreciable properties, in which the pure water flux, porosity, and bending strength were 182.50 L/m 2 ·h·bar, 9.56 %, and 37.13 MPa, respectively. Additionally, the NMS-CCMs with PMS system can remove TC from water effectively with a removal rate higher than 83.93 %. Moreover, NMS-CCMs have good catalytic stability, with the removal efficiency of TC almost unchanged after 6 repeated use cycles, and the membrane fouling could be effectively reduced by increasing the concentration of PMS. Finally, 1 O 2 was proved to be the main reactive oxygen species for TC oxidation in the NMS-CCMs/PMS system and the catalytic reaction mechanism was preliminarily proposed. It can be concluded that NMS-CCM can be successfully prepared with a relatively low sintering temperature, and it has superior bending strength, appropriate water flux, and high activity to activate PMS for degrading TC in water. The results provide a new strategy for the development of natural mineral-based catalytic ceramic membranes with low cost and high catalytic activity.