利用粉煤灰制备（介孔）活性氧化铝及其对铜离子的吸附性能表征

发布时间：2018-05-12 14:46

  本文选题：粉煤灰 + 活性氧化铝　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：活性氧化铝是一种具有多孔性的固体物料,有很大的比外表积,是具有高吸附性能的固体材料。粉煤灰是燃煤电厂排出的主要固体废物,它的氧化物组成主要为:Si O2、Al2O3、Fe O、Fe2O3等。利用粉煤灰制备活性氧化铝既可以做到废物利用,又可以生产出高附加值得吸附产品,对环境保护和工业发展都有重要意义。本论文以粉煤灰为铝(Al)源,采用酸碱联合法制备活性氧化铝,以表面活性剂为改性剂,通过有机物和无机物之间的自组装作用对其进行改性,对改性前后产物物相组成、形貌、孔隙度、孔径、比表面积进行X射线物相分析,扫描电子显微镜形貌分析,BET法比表面测定等表征;并比较地研究了改性前、后活性氧化铝对重金属离子废水中铜离子的吸附性能特征,探讨了吸附机理。本文采用粉煤灰与纯碱混合—中温烧结—浸入硫酸—过滤—煅烧的工艺制备出纯活性氧化铝。结果表明,优化工艺条件为初始纯碱与粉煤灰的质量比例:0.90:1、烧结时间为4小时(h),氢氧化铝的煅烧温度为400℃、煅烧时间为5小时(h),所得产物的比表面积为357.057m2/g,孔容为0.35cm3/g,平均孔径为4.317nm。在优化工艺条件下,分别用三种不同的改性剂(十六烷基三甲基溴化铵(CTAB)、聚乙烯亚胺(PEI)、羧酸钠)对上述活性氧化铝改性。经三种不同的改性剂改性后的产物均为纯活性氧化铝,其比表面积、孔容和平均孔径分别为:369.701 m2/g,0.37cm3/g,4.265nm(CTAB);371.942 m2/g,0.36 cm3/g,4.197nm(PEI);365.721m2/g,0.40cm3/g,4.287nm(羧酸钠)。结果表明,三种改性剂在不同程度上均提高了产物的比表面积、孔容和平均孔径,其中经PEI改性的活性氧化铝比表面积增加最明显。通过改性前后的活性氧化铝吸附重金属液中铜离子的吸附试验,在控制吸附时间,废水模拟液初始浓度,p H值等条件下对其吸附性能进行表征,结果表明,改性前的活性氧化铝吸附的最佳的p H值和吸附率分别为5和68.79%,利用不同改性剂改性后活性氧化铝吸附优化的p H值和吸附率分别为:CTAB改性的为5和75.43%,PEI改性的为3和77.02%,羧酸钠改性的为3和76.22%,经三种改性剂改性,不同程度上均提高产物对重离子废水中铜离子的吸附率。其中PEI改性效果最佳,在其最佳p H条件下,对重金属废水中铜离子吸附率达到77.02%。
[Abstract]:Active alumina is a kind of porous solid material with large specific surface product. It is a solid material with high adsorption performance. Fly ash is the main solid waste discharged from coal-fired power plants, and its oxide composition is mainly composed of:% Sio _ 2, Al _ 2O _ 3, Fe, O _ 2O _ 3 and so on. The preparation of activated alumina from fly ash can not only make use of waste, but also produce high value-added adsorbed products, which is of great significance to environmental protection and industrial development. In this paper, fly ash was used as Al source and acid-base method was used to prepare active alumina. Surfactant was used as modifier, which was modified by self-assembly between organic and inorganic compounds. The phase composition and morphology of the products before and after modification were studied. The porosity, pore size and specific surface area were characterized by X-ray phase analysis, scanning electron microscopy (SEM) morphology analysis and BET method. The adsorption characteristics of copper ion in heavy metal ion wastewater by post-activated alumina were studied, and the adsorption mechanism was discussed. In this paper, pure active alumina was prepared by mixing fly ash with soda, sintering at medium temperature, soaking in sulfuric acid, filtering and calcining. The results show that the optimum process conditions are as follows: mass ratio of initial soda to fly ash: 0.90: 1, sintering time 4 hours, calcination temperature of aluminum hydroxide 400 鈩，

本文编号：1879020