Activation Of Molecular Oxygen By Fe@Fe₂O₃for Wastewater Treatment

In recent years, with the increase of global population, the rapid development of economic and the quick process of industrialization and urbanization, environmental issues including the depletion of ozone, the destruction of forest, the land desertification, the acid rain and the water pollution, are serious threats to human survival and development. These increasingly serious environmental issues have brought great challenges to global environmental researchers. More attention has been paid to water pollution due to the importance of water resource, while to development of novel water treatment technologies with high efficiency have become the focus of attention.The biological method is one of the most common technologies for wastewater treatment; in which organic contaminant could be metabolic degraded by microorganisms under aerobic or anaerobic conditions. However, biological treatment technologies are ineffective for the macromolecule of complexity organic pollutants. Thus advanced oxidation processes become a research hotspot in this area. Activation of molecular oxygen is a friendly and noteworthy advanced oxidation technology, because of the inexpensive and safe oxidants (O2), no secondary pollution, and the good treatment effect.Previously we synthesized Fe@Fe2O3nanowires and found that Microcystis aeruginosa were rapidly degraded with FeCl3-loaded active carbon under microwave. In this study, we prepared Fe@Fe2O3/AC composition and used it to degrade DMP under microwave irradiation. We found the decomposition of DMP could be greatly enhanced over the Fe@Fe2O3/AC catalyst. The great enhanced decomposition of DMP could be attributed to the generation of active species (O2·-and·OH) by a unique microwave induced molecular oxygen activation process with Fe@Fe2O3/AC. We proposed a mechanism of molecular oxygen activation by Fe@Fe2O3/AC under microwave, that is, microwave induced electrons transferring from AC to Fe@Fe2O3to subsequently react with molecular oxygen to generate plenty of O2·-and·OH for the decomposition of DMP. In order to remediate organic pollutants at ambient temperature and pressure, we prepared three kinds of nanoscale zero-valent irons:Fe@Fe2O3nanowires, ZVI-1and ZVI-2. We studied the degradation of4-chlorophenol by activation of molecular oxygen in the presence of EDTA and air. Experimental results showed that the oxide shell of Fe@Fe2O3nanowires was thin and dense, which was benefit for the molecular oxygen activation with the highest degradation of organic pollutants. This study developed a novel oxidation method for organic pollutants degradation by molecular oxygen activation via these two catalysts; it could provide a potential theory guidance technical support for water treatment.