Comparison of SO2 and CO2 absorption by diamines

The presence of SO2 gas out of standard value at the atmosphere causes damages to humanhealth and environment. There are various methods to remove SO2 exhaust from the flue gas.One of the latest considered methods is the absorption in which diamines are used as solvent. Inthe current study, quantum density functional theory computation at gas phase was applied tostudy the absorption characteristics of SO2 and CO2. First, the optimum structure and energy ofall three diamine compounds, SO2 and CO2 were explored by the computational level of theoryB3LYP/6-31G(d,p) [1]. Then, the frequency analysis of the combinations was performed toguarantee the structures are at the ground state; notice that frequency must be positive. Studyingthe interaction of the diamines with SO2 and CO2 was carried out by introducing the gases to thediamines at the initial distance of 3 Å. Finally, the compounds at the same computational levelwere optimized and (Eabs) was obtained through the following relation; see Table 1 for the results. (...) The results show that N,N,N ,N -tetrakis (2-hydroxyethyl) ethylenediamine has the highestabsorption energy for SO2 than CO2 in comparison with other diamines. In addition, this solventshows the lowest distance from SO2.

Keywords:

Flue Gas , Absorption Energy , Diamine , DFT