用轻烧氧化镁—粉煤灰复合材料去除砷污染废水的技术研究

发布时间：2018-11-02 08:02

【摘要】：随着人们对环境重视程度的逐渐提高,越来越关心身边的环境质量,所以对环境的治理已经迫在眉睫。在众多的污染物之中,砷是一种污染极其严重的污染物,其来源广泛,例如工业排放的废水和固体垃圾填埋厂的废液中均含有砷。砷通过食物链的逐级絮集,进一步造成环境的严重的污染和对人体产生极大的损害。人们常用絮凝沉淀、物理与化学吸附、生物吸附等方法处理砷离子。轻烧氧化镁与粉煤灰复合矿物应用于砷污染废水的处理,具有便于操作、可行性高、成本低等特点。制备的轻烧氧化镁与粉煤灰复合矿物材料,可以有效的吸附水溶液中的重金属砷。本文主要以重金属砷为研究对象,将菱镁矿进行煅烧获得高活性的轻烧氧化镁,再以轻烧氧化镁-粉煤灰复合矿物材料为吸附剂,通过对普通的矿物质材料进行改性,增加其利用价值,对不同影响因素下的砷具有较好的吸附效果。首先,对复合吸附剂(轻烧氧化镁-粉煤灰)在不同条件下的改性,实验结果表明:用固液比为7g/L的复合吸附剂在混酸溶液(1mol/L HCl和1mol/L H_2SO_4)中进行酸浸渍,其中混酸(HCl:H_2SO_4)的体积比为2:1,总酸与复合吸附剂的液固比为5:1(v/m),60℃的温度下进行活化处理,在活化的过程中加入铁粉0.15 g/L,NaCl 1g/L,经过60 min的匀速搅拌,得到具有良好吸附性能的复合吸附剂。其次,探讨复合矿物材料治理砷污染废水的最佳条件。实验结果表明:复合吸附剂的用量、溶液的pH、吸附时间、吸附温度、溶液的初始浓度等因素对复合吸附剂对砷的吸附效果有影响。实验过程中,含砷溶液的初始浓度为2 mg/L,pH为9.81左右,加入吸附剂的量为2 g/L,吸附温度45℃,吸附时间90 min,改性吸附剂对砷的去除率达到85%左右,对于低浓度溶液中的砷的吸附效果达到理想预期。最后,为了探究复合吸附剂对砷(V)的吸附机理,通过扫描电镜、零电位测试对其进行表征,主要对改性吸附剂结构形态进行分析。结果表明:改性吸附剂的表面孔隙变大,比表面积变大,活性基团的数量增加,无机絮凝剂的含量增加,这些变化决定了对砷(V)具有良好的吸附效果。
[Abstract]:As people pay more and more attention to the environment, they are more and more concerned about the environmental quality around them. Among the many pollutants, arsenic is a kind of extremely serious pollution pollutant, its source is widespread, for example, the industrial waste water and the solid waste landfill waste liquid all contain arsenic. Arsenic can cause serious environmental pollution and great damage to human body through the successive flocs in the food chain. Flocculation precipitation, physical and chemical adsorption, and biological adsorption are commonly used to treat arsenic ion. The application of light burned magnesium oxide and fly ash compound minerals to the treatment of arsenic-polluted wastewater has the advantages of easy operation, high feasibility, low cost and so on. The composite mineral material of light burning magnesium oxide and fly ash can effectively adsorb arsenic in aqueous solution. In this paper, magnesium oxide with high activity was obtained by calcination of magnesite, and then the ordinary mineral material was modified by using the composite mineral material of light burning magnesium oxide and fly ash as adsorbent. By increasing its utilization value, it has a better adsorption effect on arsenic under different influence factors. First of all, the modification of composite adsorbent (light burning magnesia fly ash) under different conditions, The experimental results show that the composite adsorbent with solid / liquid ratio of 7g/L is impregnated with acid in mixed acid solution (1mol/L HCl and 1mol/L H_2SO_4), where the volume ratio of HCl:H_2SO_4 is 2: 1. The liquid-solid ratio of total acid to composite adsorbent is 5:1 (v / m), and the activation treatment is carried out at 60 鈩，

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