活性炭负载催化剂对模拟烟气中单质汞的吸附

通过浸渍法在活性炭上负载催化剂MgCl_2、CoCl_2、MnCl_2对活性炭进行改性,研究了催化剂负载量、吸附温度对活性炭吸附模拟烟气中单质汞的影响。在活性炭表面上添加无机盐MgCl_2、COCl_2、MnCl_2形成各种表面化学基团,从而加快了在炭表面对汞进行的化学吸附行为,提高活性炭的吸附能力和选择性。结果表明,在负载量为5%时,MnCl_2的改性效果最好,吸附效率提高了93%,其次是CoCl_2效率提高了90%。这在于Mn、Co这两种过渡元素价电子层结构为:(n-1)d~(1-10)ns~2,易形成杂化轨道,与单质汞发生氧化还原反应,也可以接受烟气中氧等配体的孤电子对,与活性炭表面的官能团易形成具有独特的催化性能的配合物,这种配合物作为中间产物可对汞的氧化-化学吸附起到配位催化作用,为模拟烟气中单质汞的吸附提供了适宜的反应表面。

Activated Carbon Loaded with Catalyst to Adsorb Element Mercury in Simulated Flue Gas

Activated carbon(AC)was modified via loading MnCl_2, COCl_2 and MgCl_2 by immersion method.The load amount on AC and adsorption temperature was investigated to absorb element mercury in the stimulated flue'gas.Results showed that a variety of chemical groups were formed in the surface of AC by loading MnCl_2,COCl_2 and MgCl_2, leading to improvement in AC ability and selectivity to adsorb mercury. When loading percentage was 5%,the adsorption efficiency of modified AC by MnCl_2 and COCl_2 increased significantly by 93% and 90% respectively since the transition metal Mn and Co provided suitable surface for chemical adsorption.