摘要
在湿法烟气脱硝中,Fe(Ⅱ)EDTA是一种常用的螯合剂,对NO有良好的络合吸收能力,但是Fe(Ⅱ)EDTA容易被O2氧化成对NO无络合能力的Fe(Ⅲ)EDTA。因此,选择合适的还原剂实现Fe(Ⅲ)EDTA的高效还原是络合脱硝的关键技术之一。比较了铁碳(Fe/AC)和铁粉(Fe)在不同搅拌速度下对Fe(Ⅲ)EDTA的还原,系统探讨了铁碳质量比、O2浓度、铁碳中Fe与Fe(Ⅲ)EDTA的摩尔比、pH值和Fe(Ⅲ)EDTA初始浓度对铁碳还原Fe(Ⅲ)EDTA的影响,考察了Fe/AC投加前后NO吸收效率的变化,同时通过BET、XRD表征技术对铁碳材料进行了分析。结果表明:Fe/AC能很好地再生Fe(Ⅱ)EDTA,从而提高NO吸收效率。提高搅拌速度、铁碳中Fe与Fe(Ⅲ)EDTA的摩尔比、Fe(Ⅲ)EDTA初始浓度,Fe(Ⅲ)EDTA的还原速率会相应增大;O2浓度及pH增大会降低Fe(Ⅲ)EDTA的还原速率。表征结果表明,铁碳表面形成的氢氧化物为γ-Fe OOH。
In wet flue gas denitration, Fe （ Ⅱ ） EDTA is a common chelating agent with good complexing ability to NO, but it is easily oxidized to Fe （ Ⅲ ） EDTA which have no binding capacity to NO. Thus it＇ s a key tech- nology to select proper reducing agents to regenerate Fe （ Ⅱ ） EDTA. Batch experiments were conduct to com- pare the Fe （ Ⅲ ） EDTA reduction in Fe/AC and Fe system at different stirring speed. The effects of different pa- rameters on Fe （ Ⅲ ） EDTA reduction were investigated such as the mass ratio of Fe to AC, O2concentration, the molar ratio of Fe to Fe （ Ⅲ ） EDTA, the pH value and the initial concentration of Fe （Ⅲ） EDTA. And the NO removal efficiency was also investigated without and with Fe/AC. Furthermore, Fe/AC material was analyzed by BET, XRD. The experimental results showed NO removal efficiency was improved with regeneration of Fe （ Ⅱ ） EDTA by Fe/AC. The reduction rate of Fe （ Ⅲ ） EDTA increases with the enhancement of stirring speed, the molar ratio of Fe in Fe/AC to Fe （ Ⅲ） EDTA and the initial concentration of Fe （Ⅲ ） EDTA. However, the re- duction rate of Fe （ Ⅲ ） EDTA obviously decreased when the concentration of 02 and the pH value increased. The characterization results demonstrated the surface of Fe/AC was covered with γ-FeOOH.
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第11期5943-5948,共6页
Chinese Journal of Environmental Engineering
基金
湖南省教育厅高校创新平台开放基金项目(14K094)
