飞灰未燃尽碳吸附(HgS)_n及(HgO)_n的量化分析

Quantitative Analysis of the Adsorption of (HgS)_n and (HgO)_n by Unburned Carbon in Flying Ashes

为研究飞灰中未燃尽碳对（HgS）n及（HgO）n（n=1-4）的吸附机理,构建了三碳环石墨烯结构作为未燃尽碳分子表面模型,应用密度泛函理论在B3LYP/6-31G（d）水平上进行结构优化,在PWPB95/def 2-Tzvp水平上计算了体系的单点能。研究表明：HgS及HgO团簇在未燃尽碳表面的吸附形式为化学吸附,吸附能为-646.546--105.116 k J/mol;HgS及HgO团簇以解离和非解离形式吸附于未燃尽碳表面,更倾向于稳定的解离吸附;相同情况下HgO团簇的吸附稳定性高于Hg S团簇;团簇数量的增加对吸附能几乎无影响,当吸附位点增多时,吸附能绝对值显著增加,吸附稳定性提高。

In order to study the mechanism governing the adsorption of （ HgS）, and （ HgO ） n （ n = 1 to 4 ） by unburned carbon in flying ashes, a three-carboncyclic-ring graphene structure was built to serve as a model for surface of unburned carbon molecules, the structure was optimized at the B3LYP/6-31G（d） level by using the density functional theory and the energy was calculated at the PWPB95/def 2-Tzvp level each single points in the system. It has been found that the adsorption of HgS and HgO clusters on the surface of unburned carbon pertains to a chemical one and the adsorption energy amounts to values between - 646. 546 and - 105. 116 kJ/mol. The HgS and HgO clusters are adsorbed on the surface of unburned carbon in the dissociated and non-dissociated form, more prone to a stable dissociated adsorption. Under the same conditions, the stability of HgO clusters adsorbed is higher than that of HgS clusters. To increase the number of the clusters has almost no influence on the adsorption energy. When the adsorption points increase, the absolute adsorption energy will notably increase, thus improving the adsorption stability.