¦°-complexation Adsorption Desulfurization And Denitrification Of The Theory Of Computing Research

Deep desufurization and denitrogenation by selective adsorption has become more and more important research subject. In this paper, density functional theory calculation has been employed to investigate the Ï€-complexation adsorption of aromatic sulfur compounds such as thiophene, benzothiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene and nitrogenous compounds such as pyrrole and pyridine by metal ionic exchanging faujasitetype zeolites. The calculations were based on the cluster models of 3T(H₁₁Si₂AlO₄), 16T(H₂₂Si₁₅AlO₂₂), 26T(H₃₂Si₂₅AlO₃₆) and 60T(H₅₄Si₅₉AlO₁₄₇). Two methods of Quantum Mechanics and ONIOM (Our-own-N-layer) are used to finish this wok. Natural bond orbital (NBO) calculations has been performed to investigate the Ï€-complexation adsorption mechanism of thiophene, pyrrole, pyridine and benzene on Cu(I)-Y, Ag(I)-Y, Ni(II)-Y and Zn(II)-Y sorbets. With the main findings summarized below: 1. The adsorption ability of the ion exchanging Y zeolites followed the order:Cu(I)-Y>Ag(I)-Y>Ni(II)-Y>Zn(II)-Y.2. The adsorption ability of Ï€-complexation adsorbents for thiophenic compounds is higher than for benzene.3. The adsorption ability of the alkali metals ionic exchanging Y zeolites for nitrogenous compounds followed the order: LiY>NaY>KY>CsY.4. The NBO calculations have shown that the interaction of the Cu(I),Ag(I),Ni(II) and Zn(II) with the organosufur and organic nitrogen molecules is Ï€-complexation. Namely, the Ï€ electrons of the organosufur and organic nitrogen molecules and s-orbitals of transition-metals can form σ bonds, in addition, their d-orbitals can back-donate electron density to the antibonding Ï€-orbitals of the sulfur or nitrogen...