铝孟复合金属氧化物同步去除水体中砷氟的效能研究

发布时间：2019-03-19 16:07

【摘要】：针对目前地下水体中砷氟复合污染的问题,已经被众多学者和社会所广泛关注。在众多砷、氟去除方法中,吸附法以其高效经济、简单易行的特点已经成为了人们的研究热点,并且已有研究表明吸附法对砷和氟都具有良好的去除性能。但是多数研究都致力于新材料的开发,有关于同步去除砷氟的研究也比较少,而现有的砷、氟去除技术具有一定共通性,在此基础上,寻求一种方法来同步治理水体中的砷氟本文在课题组前期研究的基础上制备出铝锰系列复合金属氧化物并研究其同步去除砷氟的效能及其在去除过程中pH值影响,在此基础上通过吸附前后吸附剂的FT-IR图谱和XPS图谱来初步探讨吸附机理。研究结果表明:(1)与活性氧化铝相比,铝锰复合吸附剂的砷氟共除能力大大增强,尤其是对于As(III),并且在更宽的pH范围内能保持对砷和氟的高吸附量。(2)在中性条件下同步去除AsF时,铝锰复合金属氧化物对As(III)、As(V)和F的吸附容量分别为0.833 mmol/g、0.839 mmol/g和5.032 mmol/g。铝锰复合金属氧化物同步去除AsF时,在12h内基本可以达到吸附平衡。吸附剂中锰含量增加有利于提高As(III)的吸附量,加快As(III)的去除速率,铝含量增加可以促进对As(V)、F的吸附,增加As(V)、F的吸附速率。应用中可根据具体水质选择适宜的铝锰配比。(3)MODAO对As(III)的吸附在酸性和碱性条件下效果更好,对As(V)的吸附量受pH影响不大,对F的吸附量在偏酸性条件下较高,碱性条件下较低。使用过程中,可根据去除对象不同适当调节pH(4)As和F都与吸附剂表面羟基基团发生反应,导致As、F的竞争吸附。F的存在可以使As的吸附量明显下降,而As的存在对F的吸附却没有太大的影响。As(III)主要被氧化为As(V)后吸附在吸附剂表面,而F吸附前后没有发生形态变化。铝锰复合金属氧化物对水体中砷氟具有良好的共除效果,特别是对As(III)的去除,是一个新的突破。吸附法去除水体砷氟操作简便,简单易行,而铝锰在自然界中来源广泛,成本低廉,因此该方法在水体中砷氟共除方面具有广阔的前景。
[Abstract]:In view of the problem of the compound pollution of the arsenic and fluorine in the underground water, it has been widely concerned by many scholars and the society. In many arsenic and fluorine removal methods, the adsorption method has become a hot spot of people's research, and has shown that the adsorption method has good removal performance for both arsenic and fluorine. However, most studies are committed to the development of new materials, and there are few studies on the simultaneous removal of arsenic and fluorine, and the existing arsenic and fluorine removal technologies have a certain common, on the basis of which, In this paper, an aluminum-manganese series composite metal oxide is prepared on the basis of the previous research of the research group, and the effect of the simultaneous removal of arsenic and fluorine and its influence on the pH value in the removal process are studied in this paper. On this basis, the adsorption mechanism was primarily discussed by the FT-IR and XPS spectra of the adsorbent before and after adsorption. The results show that (1) As compared with activated alumina, the total arsenic and fluorine co-removal capacity of the aluminum-manganese composite adsorbent is greatly enhanced, especially for As (III), and the high adsorption capacity of arsenic and fluorine can be maintained in a wider pH range. (2) The adsorption capacity of Al-Mn composite metal oxide to As (III), As (V) and F was 0.833 mmol/ g, 0.839 mmol/ g and 5.032 mmol/ g, respectively, when the AsF was removed synchronously under neutral conditions. When the Al-Mn composite metal oxide is synchronously removed by AsF, the adsorption equilibrium can be basically achieved within 12 h. The increase of the manganese content in the adsorbent is beneficial to the improvement of the adsorption capacity of As (III), the removal rate of As (III) and the increase of the aluminum content can promote the adsorption of As (V) and F, and the adsorption rate of As (V) and F can be increased. And the suitable aluminum-manganese ratio can be selected according to the specific water quality. (3) The adsorption of As (III) to As (III) is better under acidic and alkaline conditions, and the adsorption capacity of As (V) is not affected by the pH, and the adsorption of As (III) is higher under the bias acid condition and lower in alkaline condition. In that course of use, the reaction of the pH (4) As and F with the hydroxyl group on the surface of the adsorbent can be appropriately adjusted according to the difference of the removal object, leading to the competitive adsorption of As and F. The presence of F can significantly reduce the adsorption amount of As, and the presence of As does not have much influence on the adsorption of F. As (III) is mainly oxidized as As (V), it is adsorbed on the surface of the adsorbent, and no morphological change occurs before and after F adsorption. The Al-Mn composite metal oxide has a good co-removal effect on the arsenic fluorine in the water body, in particular to the removal of As (III), which is a new breakthrough. The method for removing the arsenic in the water body by the adsorption method is simple and easy to operate, and the aluminum-manganese is widely used in the natural world and has low cost, so that the method has a wide prospect in the aspects of arsenic and fluorine in the water body.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X52

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