Guan Yejun, Liu Yan, Wu Weicheng, Sun Keqiang, Li Ying, Ying Pinliang, Feng Zhaochi, Li Can
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, China.
Langmuir. 2005 Apr 26;21(9):3877-80. doi: 10.1021/la0468545.
Dibenzodioxin adsorption/desorption on solid surfaces is an important issue associated with the formation, adsorption, and emission of dioxins. Dibenzodioxin adsorption/desorption behaviors on inorganic materials (amorphous/mesoporous silica, metal oxides, and zeolites) were investigated using in situ FT-IR spectroscopy and thermogravimetric (TG) analysis. Desorption temperatures of adsorbed dibenzodioxin are very different for different kinds of inorganic materials: approximately 200 degrees C for amorphous/mesoporous silica, approximately 230 degrees C for metal oxides, and approximately 450 degrees C for NaY and mordenite zeolites. The adsorption of dibenzodioxin can be grouped into three categories according to the red shifts of the IR band at 1496 cm(-1) of the aromatic ring for the adsorbed dibenzodioxin: a shift of 6 cm(-1) for amorphous/mesoporous silica, a shift of 10 cm(-1) for metal oxides, and a shift of 14 cm(-1) for NaY and mordenite, suggesting that the IR shifts are proposed to associated with the strength of the interaction between adsorbed dibenzodioxin and the inorganic materials. It is proposed that the dibenzodioxin adsorption is mainly via the following three interactions: hydrogen bonding with the surface hydroxyl groups on amorphous/mesoporous silica, complexation with Lewis acid sites on metal oxides, and confinement effect of pores of mordenite and NaY with pore size close to the molecular size of dibenzodioxin.
二苯并二恶英在固体表面的吸附/解吸是与二恶英的形成、吸附和排放相关的一个重要问题。利用原位傅里叶变换红外光谱（FT-IR）和热重（TG）分析研究了二苯并二恶英在无机材料（无定形/介孔二氧化硅、金属氧化物和沸石）上的吸附/解吸行为。对于不同种类的无机材料，吸附的二苯并二恶英的解吸温度差异很大：无定形/介孔二氧化硅约为200℃，金属氧化物约为230℃，NaY和丝光沸石约为450℃。根据吸附的二苯并二恶英在1496 cm-1处芳环红外谱带的红移，二苯并二恶英的吸附可分为三类：无定形/介孔二氧化硅红移6 cm-1，金属氧化物红移10 cm-1，NaY和丝光沸石红移14 cm-1，这表明红外谱带红移与吸附的二苯并二恶英和无机材料之间相互作用的强度有关。提出二苯并二恶英的吸附主要通过以下三种相互作用：与无定形/介孔二氧化硅表面羟基形成氢键、与金属氧化物上的路易斯酸位点络合以及孔径接近二苯并二恶英分子大小的丝光沸石和NaY的孔道限域效应。
