Research On Modified Fly Ash In The Ozone-fly Ash Combined System

With the quantity of coal fly ash emissions has been increased year by year, the utilization of coal fly ash has gained more and more attention. Dicamba is a common herbicide pollutant. The contamination of dicamba in aqueous solution has dangers to human health and the environment. Ozone oxidation technology has many advantages that including the strong ability of oxidation, no secondary pollution, easy operation and management, etc. Ozone oxidation technology is suitable for the degradation of pesticide in water contaminant. However, ozone oxidation technology operating costs is high. So we need to add a catalyst to promote the effective use of ozone.In order to find an effective method to degrade dicamba in aqueous solution and make use of fly ash, dicamba is selected as the model pollutant to be degraded using ozonation assisted by fly ash in a bubble reactor. In this paper, fly ash was modified in order to improve the degradation efficiency. Fly ash modified include synthetic zeolites, and forming study of fly ash.Fly ash as the main raw material compound zeolites by hydrothermal crystallization. Fly ash add some adjuvants and prepared granule. This modified fly ash was identified by SEM, XRD, BET, and laser particle sizer measurements as well,researching the structure and properties of the fly ash, zeolite and granule.Through those researches, we could draw those conclusions: the promoting effect of modified-fly ash to ozonation process was more obvious than the unmodified,in the processing of reaction, there was synergistic effect between fly ash and ozone.The pH of the solution changed which was caused by the modified fly ash. The experiment results showed that the main factor of promoting effect was not the changed pH of solution. With the increase of react time, the dicamba degraded gradually by losing chlorine elements and the concentration of chlorion increased.The oxidative degradation process of dicamba between fly ash and ozone could belong to indirect reaction of hydroxyl radical. With the increase of cycle times of the modified fly ash, the degradation effect of dicamba became low gradually, even so,after use of four times, the removal efficiency of the modified fly ash were still higher than that use only ozone, drawing the conclusion that the doped fly ash had favorable stability.Fly ash synthetic zeolite can get better degradation efficiency of dicamba greatly.It improves the utilization of ozone, meanwhile, it reduces the ozone input. Granule more easily separated from the water. Granule easy to recycle. This paper lays afoundation in practical application of the combined technology of ozonation assisted by fly ash in water treatment.