V_2O_5/AC在含SO_2气氛中对气态Hg^0的吸附脱除研究  

Adsorption and Removal of Gas-Phase Hg^0 over a V_2O_5/AC Catalyst in the Presence of SO_2

作　　者：王钧伟[1,2] 杨建丽[1] 刘振宇[3] 

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,太原030001 [2]中国科学院研究生院,北京100049 [3]北京化工大学化工资源有效利用国家重点实验室,北京100029

出　　处：《环境科学》2009年第12期3455-3460,共6页Environmental Science

基　　金：国家自然科学基金重点项目(20736001);煤转化国家重点实验室自主研究课题项目(09BWLA1942);国家高技术研究发展计划(863)项目(2007AA05Z310)

摘　　要：利用固定床反应器研究了模拟烟气(N2、SO2、O2)气氛下,气态Hg0在V2O5/AC催化剂上的吸附脱除行为.考察了V2O5担载量、SO2浓度和吸附温度等对V2O5/AC吸附脱除Hg0的影响,并对V2O5/AC上吸附汞的形态进行了XPS分析表征.研究发现,V2O5/AC对Hg0的吸附能力远大于载体AC.汞的吸附量与V2O5/AC中V2O5的质量分数有关,随着V2O5质量分数从0.5%增加到1.0%,汞的吸附量从75.9μg.g-1增加到89.6μg.g-1(无氧)和115.9μg.g-1增加到185.5μg.g-1(有氧),远高于相同吸附条件下的AC上的汞吸附量(9.6μg.g-1和23.3μg.g-1).SO2对Hg0的吸附有促进作用,主要是由于SO2和Hg0在V2O5/AC上发生了化学反应.但是当SO2体积分数从500×10-6增加到2 000×10-6时,V2O5/AC对汞的吸附量只增加了5%.不同温度下的实验结果表明,V2O5/AC催化剂在150℃左右的吸附脱除Hg0的能力最高,汞的吸附量达到98.5μg.g-1(无氧)和187.7μg.g-1(有氧).XPS分析结果表明,在V2O5/AC催化剂表面有HgO和HgSO4生成,证实了V2O5和SO2的作用.The adsorption and removal behaviors of gas-phase Hg^0 over V： 05/AC and AC were studied under a simulated flue gas （containing N2, SO2, 02 ） in a fixed-bed reactor. The influences of the V2O5 loading, SO2 concentration and adsorption temperature on Hg^0 adsorption were investigated. The speciation of mercury adsorbed was determined by X-ray photoelectron spectroscopy （XPS）. It was found that the V2O5/ AC catalyst has a much higher capability than AC for Hg^0 adsorption and removal, mainly because of the catalytic oxidation activity of V2O5 . The Hg^0 adsorption capability depends on the V2O5 content of the V2O5/AC catalyst. The amounts of mercury adsorbed increase from 75.9 μg·g^-1 to 89.6μg·g^-1 （in the absence of 02） and from 115.9 μg·g^-1 to 185.5μg·g^-1 （in the presence of O2） as the V2O5 loading increases from 0.5% to 1.0% ,which are much higher than those over AC under the same conditions （9.6μg·g^-1 and 23.3 μg·g^-1）. SO2 in the flue gas enhances Hg^0 adsorption over the V2O5/AC catalyst, which is due to the reaction of SO2 and Hg^0 on V2O5/AC. But as the SO2 concentration increases from 500 × 10^-6 to 2 000 ×10^-6 , the amount of mercury adsorbed has only a slight increase. The optimal temperature for Hg^0 adsorption over the V2O5/AC catalyst is around 150μ℃, at which the amounts of mercury adsorbed are up to 98.μg·g^-1（in the absence of 02 ） and 187.7 μg·g^-1 （in the presence of O2 ） . The XPS results indicate the formation of HgO and HgSO4 on the surface of the V2 O5/AC catalyst, which confirms the role of V2O5 and SO2 .

关 键 词：V2O5/AC SO2 气态Hg^0 吸附 脱除 

分 类 号：X701[环境科学与工程—环境工程]