锰负载对磁性铁氧化物吸附Hg^0的影响

EFFECT OF MANGANESE LOADING ON ZERO VALENT MERCURY ADSORPTION ON MAGNETIC IRON OXIDES

针对催化氧化脱汞存在催化剂难以回收和抗硫性能差的问题,采用共沉淀法合成纳米磁流体粒子,并负载Mn氧化物得到Mn/γ-Fe2O3,同时通过固定床吸附实验考察了吸附剂对模拟烟气中汞吸附的特性及规律,探讨了吸附剂对汞的吸附机理。结果表明:磁性Mn/γ-Fe2O3复合纳米颗粒在模拟烟气条件下对汞表现出优异的吸附性能,在<200℃时,500min内平均穿透率达到13%,且几乎不受SO2的影响,表现出良好的耐受性。零价汞吸附的反应机制主要遵循Mars-Maessen机制,无氧情况下,主要由金属氧化物提供晶格氧参与反应,反应生成弱吸附态汞产物;有氧条件下,金属氧化物消耗的晶格氧能够得到补充,并且在O2的助力下形成强吸附态产物。

In order to overcome the difficulties in catalyst recovery and poor sulfur resistance in catalytic oxidative mercury removal, nano-magnetic fluid particles were synthesized by coprecipitation method, and then Mn/γ-Fe 2O 3 was obtained by loading Mn oxide.At the same time, the adsorption characteristics and rules of adsorbents for mercury in simulated flue gas were investigated by fixed bed adsorption experiments, and the adsorption mechanism of adsorbents for mercury was discussed.The results showed that the magnetic Mn/γ-Fe 2O 3 composite nanoparticles exhibited excellent adsorption properties on mercury under simulated flue gas conditions.The average penetration rate reached 13% within 500 min at 200 ℃;and at 200 ℃, they are hardly affected by SO 2, showing good tolerance.The reaction mechanism of zero-valent mercury adsorption mainly followed Mars-Maessen mechanism.In the absence of oxygen, lattice oxygen was mainly supplied by metal oxides to participate in the reaction, and weak adsorbed mercury products were formed.Under aerobic conditions, lattice oxygen consumed by metal oxides could be supplemented, and strong adsorbed products could be formed with the participation of oxygen.