改性粉煤灰复合催化剂制备及降解2-氯酚研究
发布时间：2018-09-04 11:22
【摘要】：粉煤灰是以煤为能源电厂发电产生的废弃物,本课题以内蒙古的粉煤灰为原料,通过对粉煤灰EDTA水热改性后,共沉淀Fe制备复合催化剂,主要使用扫描电子显微镜(SEM)、比表面积(BET)、傅里叶转换红外光谱(FTIR)、热重(TGA)、X射线光电子能谱分析(XPS)等手段对复合催化剂的形貌结构、表面性质、热稳定性等进行了表征。实验室研究以2-氯酚模拟废水中的苯系污染物,建立臭氧催化氧化体系进行废水氧化降解研究。中试试验应用到煤化工MTO汽提塔外排污水中,主要结论如下：(1)利用0.05 mol/L的EDTA对粉煤灰通过水浴加热方法表面改性,Al、Si含量升高。活化改性后共沉淀Fe制备粉煤灰基复合催化剂,扫描电镜SEM分析FA-A基复合催化剂具有不规则,多孔的表面,BET增大到200.3 m2/g；热重TGA分析在600℃左右具有良好的热稳定性：红外光谱FTIR分析FA-A基复合催化剂没有明显的基团变化；XPS分析载铁FA-A基复合催化剂负载了一定量的铁氧化物,其中含有二价和三价铁。(2)载铁粉煤灰基复合催化剂臭氧催化降解2-氯酚：①液固比为5：1(mL/g),2-氯酚的初始浓度为200 mg/L,在pH为9时,催化臭氧化降解2-氯酚的去除效率提高了40.57%-57.21%。②不同液固比下2：1、5：1、10：1(mL/g),液固比2：1的2-氯酚催化氧化的去除效率较好。③液固比为10:1 (mL/g),100mg/L、200 mg/L、 500 mg/L、1000mg/L的2-氯酚,100 mg/L的2-氯酚的去除效率较高,但测定的2-氯酚降解的量是逐渐降低的。④2-氯酚初始浓度为200 mg/L,液固比为10：1(mL/g),添加叔丁醇的量为5mmol/L,叔丁醇的添加更加明显抑制了单独臭氧过程中2-氯酚的去除效率,而对催化臭氧过程抑制效果的影响降低。⑤臭氧氧化降解2-氯酚的过程遵循准一级动力学模型,对于单独臭氧、粉煤灰、载铁FA-A基催化剂来说,臭氧氧化降解2-氯酚的动力学反应速率常数分别为0.03、0.05、0.1 min-1。2-氯酚通过臭氧催化氧化首先降解为邻苯二醌；然后邻苯二醌中间产物氧化开环,转化为己二烯二酸、马来酸、草酸等中间产物；最后上述有机酸降解为二氧化碳的过程。(3)MTO汽提塔外排污水中试及载铁复合催化剂机理研究：利用臭氧催化氧化与分离技术对MTO汽提塔外排污水进行处理,出水指标符合仪表冲洗水指标。载铁FA-A基复合催化剂的加入,促进产生了更多的羟基自由基,吸附在催化剂表面上的有机物直接与臭氧发生氧化作用,也可以与羟基自由基发生间接的氧化作用。
[Abstract]:Fly ash is a kind of waste produced by coal-fired power plant. In this paper, fly ash from Inner Mongolia was used as raw material, after hydrothermal modification of fly ash EDTA, composite catalyst was prepared by coprecipitation of Fe. The morphology, surface properties and thermal stability of the composite catalysts were characterized by scanning electron microscopy (SEM), specific surface area (SEM), (BET), Fourier transform infrared spectroscopy (FTIR), (FTIR), thermogravimetric (TGA) (TGA) and X-ray photoelectron spectroscopy (XPS). In the laboratory, 2-chlorophenol was used to simulate benzene pollutants in wastewater, and ozone catalytic oxidation system was established to study the degradation of wastewater. The main conclusions are as follows: (1) the surface modification of fly ash by water bath heating method with EDTA of 0.05 mol/L is used to increase the content of MTO Si. The composite catalyst based on fly ash was prepared by co-precipitation of Fe after activation. SEM analysis showed that the composite catalyst based on FA-A was irregular and the porous surface increased to 200.3 m2 / g. The thermogravimetric TGA analysis shows good thermal stability at about 600 鈩，
本文编号：2221942
[Abstract]:Fly ash is a kind of waste produced by coal-fired power plant. In this paper, fly ash from Inner Mongolia was used as raw material, after hydrothermal modification of fly ash EDTA, composite catalyst was prepared by coprecipitation of Fe. The morphology, surface properties and thermal stability of the composite catalysts were characterized by scanning electron microscopy (SEM), specific surface area (SEM), (BET), Fourier transform infrared spectroscopy (FTIR), (FTIR), thermogravimetric (TGA) (TGA) and X-ray photoelectron spectroscopy (XPS). In the laboratory, 2-chlorophenol was used to simulate benzene pollutants in wastewater, and ozone catalytic oxidation system was established to study the degradation of wastewater. The main conclusions are as follows: (1) the surface modification of fly ash by water bath heating method with EDTA of 0.05 mol/L is used to increase the content of MTO Si. The composite catalyst based on fly ash was prepared by co-precipitation of Fe after activation. SEM analysis showed that the composite catalyst based on FA-A was irregular and the porous surface increased to 200.3 m2 / g. The thermogravimetric TGA analysis shows good thermal stability at about 600 鈩，
本文编号：2221942
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