微孔沸石对卷烟烟气中多环芳烃去除的机理研究

The mechanism of micropore zeolites removing polycyclic aromatic hydrocarbons in cigarette smoke

通过多环芳烃(polycyclic aromatic hydrocarbon,PAHs)荧蒽(fluoranthene,Flu)和蒽(anthracene,Ant)在微孔沸石Y、ZSM-5和NaA上的吸附和催化裂解实验,探讨了沸石对卷烟烟气中PAHs选择性去除作用机理。实验结果表明:Y型沸石能吸附和催化裂解Flu和Ant;ZSM-5沸石能吸附和催化裂解Ant而不能吸附Flu;NaA沸石受孔径限制,不能吸附和催化裂解Ant和Flu。然而,将这些沸石添加到卷烟中,它们都不同程度地减少了烟气中B[a]P、Ant和Flu的含量。结合沸石吸附PAHs的红外图谱及量子化学计算结果:微孔沸石对卷烟烟气中PAHs的去除不是直接吸附或催化降解,而是吸附了形成PAHs的中间体/前体从而减少了PAHs的生成。

Mechanism of zeolite selectively reducing polycyclic aromatic hydrocarbon （PAHs） in cigarette smoke was analyzed through adsorption and catalytic cracking experiments of two PAHs, fluoranthene （Flu） and anthracene （Ant）, in zeolite Y, ZSM-5, and NaA. Results indicated that zeolite Y can adsorb both Flu and Ant while zeolite ZSM-5 can only adsorb Ant. However, both zeolites can catalyze Flu and Ant. Zeolite NaA can not adsorb and catalyze Ant nor Flu due to its small pore diameter. Nevertheless, when these zeolites were added into cigarettes filter, the content of B[a]P, Ant, and Flu in smoke were all decreased. Considering with the FTIR spectra of zeolites adsorbing PAHs and theoretical calculation by quantum chemistry, a reasonable conclusion could be made that the removal of PAHs by zeolites was not caused by direct adsorption or catalytic cracking but caused by the adsorption of intermediates or precursors which may inhibit the formation of PAHs.