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稀土亞鉻酸鹽的合成及介孔材料降低卷煙煙氣中鉻和鎘釋放量的研究

發(fā)布時(shí)間:2018-09-02 08:41
【摘要】:本論文的研究主要包括兩個(gè)部分:采用水熱法合成了稀土亞鉻酸鹽微米材料,包括正交相的PrCrO3正方體粒子和正交相的NdCrO3橢圓片狀粒子,通過(guò)X射線光電子能譜、X射線衍射、場(chǎng)發(fā)射掃描電鏡等方法對(duì)材料的結(jié)構(gòu)和形貌進(jìn)行了表征,優(yōu)化了合成其較佳結(jié)構(gòu)和形貌的反應(yīng)參數(shù)。提出了各物質(zhì)不同形貌的可能生長(zhǎng)機(jī)理,研究了材料的磁性質(zhì);采用浸漬法制備了EDTA-4Na/γ-Al2O3介孔復(fù)合體納米材料,通過(guò)熱重分析、X射線衍射、透射電子顯微鏡等方法對(duì)材料的結(jié)構(gòu)和性能進(jìn)行了表征。探究了該材料在降低卷煙主流煙氣中重金屬釋放量上的應(yīng)用。論文的主要研究工作總結(jié)如下: (1)采用簡(jiǎn)單一步水熱法合成了正交相的PrCrO3正方體粒子,制備方法簡(jiǎn)單,產(chǎn)物結(jié)晶度較好,通過(guò)XRD、 XPS. FTIR、 FESEM等方法對(duì)合成的產(chǎn)物進(jìn)行了表征,確定了合成PrCrO3正方體粒子的較佳反應(yīng)條件為反應(yīng)溫度280℃,反應(yīng)時(shí)間7天,Pr3+與Cr3+摩爾比1:1,溶液堿度8mol/dm3。研究了PrCrO3正方體粒子可能的形成機(jī)理。探討了其磁性質(zhì)。結(jié)果表明PrCrO3正方體粒子表現(xiàn)出磁相變和負(fù)磁化性質(zhì)。其尼爾溫度約為232K,4K下的磁滯回線表明該材料的矯頑力和剩磁分別為17280e和4.88emu/g,與之前報(bào)道的PrCrO3材料的尼爾溫度、矯頑力和剩磁有小的偏差,這可能是材料的不同形貌和尺寸大小導(dǎo)致的原因,然而更深入地理解其磁性質(zhì)有待進(jìn)一步的研究。采用類(lèi)似的方法制備了正交相的NdCrO3橢圓片狀粒子,確定了合成NdCrO3橢圓片狀粒子的較佳反應(yīng)條件為反應(yīng)溫度280℃,反應(yīng)時(shí)間3天,Nd3+與Cr3+摩爾比0.56:1,溶液堿度8mol/dm3。提出了NdCrO3橢圓片狀粒子形成的可能機(jī)理,研究了其磁性質(zhì)。 (2)采用浸漬法制備了介孔復(fù)合體EDTA-4Na/y-Al2O3,利用TEM、 XRD口TG等對(duì)材料的結(jié)構(gòu)和性能進(jìn)行了表征,將介孔復(fù)合體EDTA-4Na/γ-Al2O3添加到濾棒中,制成添加了介孔復(fù)合體的特種二元復(fù)合濾棒,并制成卷煙,考察其對(duì)卷煙主流煙氣中鉻和鎘釋放量的影響。結(jié)果表明:將介孔復(fù)合體EDTA-4Na/γ-Al2O3按每支濾嘴16.25mg的添加量添加到二元復(fù)合濾棒中,可使卷煙主流煙氣中的鉻和鎘釋放量分別降低‘33.2%和31.1%。同時(shí)還研究了介孔復(fù)合體EDTA-4Na/γ-Al2O3降低卷煙主流煙氣中鉻和鎘釋放量的可能機(jī)理,主要有吸附截留和絡(luò)合截留兩種。
[Abstract]:The research of this thesis mainly includes two parts: rare earth subchromate micron materials were synthesized by hydrothermal method, including the PrCrO3 cube particles in the orthotropic phase and the NdCrO3 elliptic sheet particles in the orthotropic phase, and the X-ray diffraction was carried out by X-ray photoelectron spectroscopy (XPS). The structure and morphology of the materials were characterized by field emission scanning electron microscopy, and the optimum reaction parameters of their structures and morphologies were optimized. The possible growth mechanism of different morphologies of various substances and the magnetic properties of the materials were studied. EDTA-4Na/ 緯 -Al 2O 3 mesoporous nanocomposites were prepared by impregnation method and were characterized by thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The structure and properties of the materials were characterized by transmission electron microscopy (TEM). The application of this material in reducing heavy metal emission from mainstream cigarette smoke was investigated. The main work of this paper is summarized as follows: (1) the orthotropic PrCrO3 cube particles were synthesized by a simple one step hydrothermal method. The preparation method is simple and the crystallinity of the product is better. The synthesized product was characterized by FTIR, FESEM and other methods. The optimum reaction conditions were determined as follows: reaction temperature 280 鈩,

本文編號(hào):2218839

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