负载纳米零价铁铜藻基活性炭去除水中六价铬

发布时间：2018-05-24 15:03

  本文选题：铜藻 + 活性炭　； 参考：《浙江工业大学》2015年硕士论文

【摘要】：纳米零价铁是一种比表面积大、反应活性高的纳米材料,常被用于去除水中六价铬的研究,由于纳米零价铁粒径小、易团聚,在实际工程应用中受到了一定的限制。将纳米零价铁固定在载体上从而提高其分散度是解决这一问题的有效方法。活性炭作为一种良好的载体,性质稳定,且具有发达的孔道结构,有利于纳米零价铁铁粒子的固定。将活性炭和纳米零价铁结合,能分散负载的纳米零价铁颗粒,有效阻止其团聚,提高了纳米零价铁修复污染物的效率,同时能够对高浓度(90-120 mg·L-1)的含六价铬工业废水高效处理。本文以铜藻基活性炭为载体,分别采用初湿含浸法、中温焙烧法和液相还原法制备负载纳米零价铁铜藻基活性炭(NZVI/SAC);将负载纳米零价铁前后的铜藻基活性炭应用于模拟废水中的Cr(Ⅵ)去除,考察了不同反应条件对反应过程的影响,并对去除过程进行了动力学分析和热力学分析,同时通过分别分析溶液中总铬、六价铬的浓度变化和NZVI/SAC去除六价铬前后材料表面的XPS谱图,对六价铬的去除机制进行了探讨。结果表明:(1)负载纳米零价铁铜藻基活性炭(NZVI/SAC)能够有效地改善纳米铁团聚现象,适用于高浓度(90-120 mg·L-1)六价铬工业废水的处理,其对六价铬的去除效果可满足国家规定的六价铬排放标准,回收效果表明该复合吸附材料对环境无次级污染且性能稳定,是一种高性能的复合吸附材料。(2)负载纳米零价铁铜藻基活性炭的制备条件为焙烧时间240 min,焙烧温度300℃,升温速率10℃·min-1,还原时间120 min,还原温度5℃,原料摩尔比为1:5,制备过程在无氧条件下进行。制备的负载纳米零价铁铜藻基活性炭上的纳米零价铁颗粒以50-150 nm球状形态存在,且其吸附性能明显优于普通铁粉、纳米零价铁和铜藻基活性炭。(3)当NZVI负载量为30%、pH为2、温度为30℃、用量为2 g·L-1条件下NZVI/SAC可在10 min内快速将100 mg·L-1的Cr(Ⅵ)去除,且去除率达100%;随Cr(Ⅵ)初始浓度的增高,去除率逐渐降低。NZVI/SAC通过化学还原和吸附共同作用将水中的六价铬去除,且以化学还原作用为主。(4)NZVI/SAC对水中Cr(Ⅵ)的吸附速率可用伪一级和伪二级动力学模型拟合,吸附等温线可用于Langmuir和Freundlich型吸附等温模型拟合。(5)NZVI/SAC对水中的Cr(Ⅵ)具有良好的选择性,且在处理过程中对Ni2+有一定的去除能力,为进一步研究其实用价值提供了一定的理论依据。
[Abstract]:Nanocrystalline zero-valent iron is a kind of nano-material with large specific surface area and high reactive activity. It is often used to remove hexavalent chromium from water. Due to its small particle size and easy agglomeration, it is limited in practical application. It is an effective way to solve this problem by immobilization of nanometer zero valent iron onto the carrier to improve its dispersion. As a good carrier, activated carbon has stable properties and developed pore structure, which is conducive to the immobilization of iron nanoparticles with zero valence. The combination of activated carbon and nanometer zero-valent iron can disperse the loaded nano-zero-valent iron particles, effectively prevent their agglomeration, and improve the efficiency of remediation of pollutants by nano-zero-valent iron. At the same time, it can efficiently treat the wastewater containing hexavalent chromium with high concentration of 90 ~ 120 mg / L ~ (-1). In this paper, the copper algae-based activated carbon was used as carrier, and the initial wet leaching method was used respectively. NZVI / SACU was prepared by medium temperature roasting and liquid phase reduction method, and the effect of different reaction conditions on the reaction process was investigated by using the Cu (鈪，

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