| Coal-fired power plants and industrial boilers are major sources of arsenic pollution, in the context of the growing volume of coal-fired, the emission of arsenic in the coal-fired flue gas increases year by year, industrial waste water emissions of chemical, metallurgical and power plant also contains a lot of heavy metal ions, such as arsenic, mercury, lead, chromium and the like. Heavy metals arsenic, mercury and other pollutions in the flue gas and industrial waste are important issues that threaten human health and the environment.This paper outlines the arsenic pollution hazards to human and ecological environment, and describes the current status of the source and arsenic emissions. This paper details the existing adsorption of arsenic and technology at home and abroad and method for controlling emissions of arsenic, activated carbon for most trace heavy metal elements has a strong adsorption capacity, but the cost of large-scale use is too high. Therefore, to develop a low cost and good adsorption performance of adsorbent now become the focus of academic inquiry.Fly ash is a waste of coal-fired power plant emissions. In recent years, China’s annual emissions were over 300 million tons of ash. The utilization of fly ash is not high, mainly for the production, irrigation, application of road works, as well as part of the application materials in the field of agriculture, etc., most of the rest of fly ash are stacked idle, On the one hand take up a lot of arable land, is a waste of land resources, on the other hand due to the ash particle size is small and light weight, easy to be blown up, floating in the air, causing serious pollution to the atmosphere, so the powder comprehensive utilization of fly ash has been attracted environmentalists’and researchers’attention, and also need to focus on environmental science research. Since fly ash with porous, large surface area and other physical properties and chemical properties of more calcium, iron active sites and the like, and therefore it can absorb industrial waste gas and wastewater heavy metal pollutants, combined with fly ash inexpensive, low cost, in recent years, the use of fly ash processing has a good prospect of flue gas and wastewater heavy metals and other pollutants. However, due to the adsorption capacity of the fly ash itself is not ideal, in practice before being put into production, need physical extraction and modified to make it more conducive to treat flue gas and wastewater pollutants.Eight kinds of fly ashes are used in this paper’experiment, including three species of Pulverized Coal (PC) of the fly ash and five species circulating fluidized bed boiler (CFB) of fly ash. Fly ash samples were XRD, SEM, BET, XRF and other study the microstructure and composition of its molecular composition and the like.Based on iron component in the fly ash has significant arsenic removal effect, and the use of fly ash in the flue gas of its own iron component control arsenic emissions have cheap, no effect on the use of fly ash, no secondary pollution, and other advantages, therefore proposed that separate the high and enrichment iron content ferrosphere of fly ash from power plants, which focuses on the characteristics of removing of heavy metals as arsenic from coal-fired flue gas, reveal the mechanism of arsenic removal. We designed a gaseous reaction and fixed bed adsorption of arsenic occur integration experimental device; wet magnetic separation methods enriched a high iron content in the fly ash beads, which reached 50% Fe2O3 content; study the feature of arsenic removal on fly ash, ferrosphere, exploring the physical properties of the fly ash and the ferrosphere and the temperature of external flue gas on the impact of arsenic removal mechanism. The development of the adsorbent in a fixed bed adsorption homemade adsorption experiments on the reaction of gaseous arsenic integration experimental device, experimental results show that the ferrosphere adsorption capacity of arsenic removal is enhanced greatly than the corresponding fly ash.Previous studies have been referenced, using alkali fusion, pickling situ synthesis method of combining fly ash was modified by increasing the activity of the modified sorbent adsorption sites, increasing the pore structure and increase surface area. The developed adsorbent proceeded arsenic adsorption experiments in simulated containing arsenic wastewater, compared with the original ash, showing good adsorption properties. |
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