本文關(guān)鍵詞： 介孔材料 磁性核殼結(jié)構(gòu) 功能化 光催化 吸附　出處：《西安建筑科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：工業(yè)廢水的大量排放,使得環(huán)境壓力越來越大。其中冶金工業(yè)中的重金屬廢水和染料廢水的污染尤為嚴(yán)重。由于傳統(tǒng)的物理法、化學(xué)法和生物法處理廢水存在成本昂貴、二次污染和出水難以達(dá)到國家排放標(biāo)準(zhǔn)的問題。所以亟待尋找新型的廢水處理辦法,近年來以介孔氧化硅作為載體的吸附劑或光催化劑的功能材料,被廣泛運用于重金屬吸附和光催化領(lǐng)域。但是如何高效的利用介孔材料發(fā)達(dá)的孔道結(jié)構(gòu)和光催化劑(TiO_2)仍然困擾著人們。故而研發(fā)可回收的、利用率高的介孔氧化硅吸附劑或光催化劑是目前熱點的研究課題。本文采用溶劑熱法制備了納米四氧化三鐵微球,采用改進(jìn)St?ber法制備了核殼結(jié)構(gòu)的磁性介孔氧化硅材料。通過掃描電鏡(SEM)和透射電鏡(TEM)對材料的形貌特征進(jìn)行表征分析,發(fā)現(xiàn)可以改變正硅酸乙酯(TEOS)的添加量,可以得到不同尺寸介孔二氧化硅殼層。合成磁性介孔氧化硅的最佳的制備條件為:0.15g Fe_3O_4、0.45mL正硅酸乙酯(TEOS),醇水比(V:V)為3:4,0.6g十六烷基三甲基溴化銨(CTAB),反應(yīng)時間12h。此時制備的磁性介孔氧化硅分散性良好,具備很好的核殼結(jié)構(gòu),磁飽和強(qiáng)度在30.97emu·g~(-1)。在磁性介孔氧化硅基礎(chǔ)上采用浸漬法制備了“磁核-介孔硅-半導(dǎo)體”三元體系光催化劑,研究了負(fù)載不同量TiO_2的光催化劑降解亞甲基藍(lán)的性能,發(fā)現(xiàn)鈦酸四丁酯(TBOT)的添加量為2.5mL的Fe_3O_4@SiO_2@mSiO_2@TiO_2光催化劑催化效率最高。研究發(fā)現(xiàn)是由于磁性介孔氧化硅特殊的孔道結(jié)構(gòu),使得二氧化鈦在結(jié)晶時被限制,在特殊的孔道內(nèi)部生長為納米顆粒,納米尺寸的二氧化鈦結(jié)構(gòu)使得光生空穴-電子對的復(fù)合概率降低,從而提高了光生載流子濃度,進(jìn)一步提高其光催化性能。通過研究不同pH和溫度下復(fù)合光催化劑降解亞甲基藍(lán),得出在25℃,pH=7時,復(fù)合光催化劑降解效率最高。為了進(jìn)一步探究磁性介孔氧化硅的吸附性能,我們在磁性介孔氧化硅基礎(chǔ)上合成了氨基化修飾的磁性介孔氧化硅復(fù)合材料。通過N_2吸脫附測試,得到氨基功能化的磁性核殼微球的比表面積和孔容分別為413.46 m2·g~(-1)和0.21 cm~3·g~(-1)。氨基功能化磁性介孔氧化硅吸附Cr(Ⅵ)的過程中以準(zhǔn)二級動力學(xué)模型為主,其吸附Cr(Ⅵ)的機(jī)理是溶液中離子形態(tài)的Cr(Ⅵ)與氨基化修飾的磁性介孔氧化硅復(fù)合材料表面的氨基通過電子共用或靜電作用實現(xiàn)的。
[Abstract]:The heavy metal and dyestuff wastewater in metallurgical industry are especially polluted because of the traditional physical method. The treatment of wastewater by chemical and biological methods is expensive, the secondary pollution and effluent are difficult to meet the national discharge standards, so it is urgent to find a new treatment method of wastewater. In recent years, mesoporous silica as a carrier adsorbent or photocatalyst functional materials. It is widely used in the field of heavy metal adsorption and photocatalysis. However, how to efficiently utilize the developed pore structure of mesoporous materials and photocatalyst TiO2 still puzzles people. Mesoporous silica adsorbent or photocatalyst with high utilization rate is a hot research topic at present. In this paper, nano-sized ferric trioxide microspheres were prepared by solvothermal method, and modified St3 microspheres were used. Magnetic mesoporous silica materials with core-shell structure were prepared by ber method. The morphologies of the materials were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the addition of tetraethyl orthosilicate (TEOS) could be changed. The mesoporous silica shell with different sizes can be obtained. The optimum preparation conditions for the synthesis of magnetic mesoporous silica are as follows: 0.15g Fe3O-1, 0.45ml tetraethyl orthosilicate (TEOS). The ratio of alcohol to water (V: v) is 3: 4 0. 6 g cetyltrimethylammonium bromide (CTABN), and the reaction time is 12 h. The magnetic mesoporous silicon oxide has good dispersion and good core-shell structure. The magnetic saturation intensity is 30.97 emu 路g ~ (-1). On the basis of magnetic mesoporous silicon oxide, a ternary system of "magnetic nucleus-mesoporous silicon-semiconductor" photocatalyst is prepared by impregnation method. The degradation of methylene blue with different amount of TiO_2 photocatalyst was studied. It was found that tetrabutyl titanate (TBOT). The addition of 2.5 mL Fe_3O_4@SiO_2@mSiO_2@TiO_2 photocatalyst has the highest catalytic efficiency. It is found that the special pore structure of magnetic mesoporous silicon oxide is the main reason. The TIO _ 2 is limited in crystallization and grows into nanocrystalline particles in a special pore. The nano-sized TIO _ 2 structure reduces the recombination probability of photogenerated hole-electron pairs. Therefore, the photocatalytic activity was further improved by increasing the concentration of photogenerated carriers. By studying the degradation of methylene blue by the composite photocatalyst at different pH and temperature, it was found that pH = 7:00 at 25 鈩，

本文編號：1460524