超声强化含铁矿石及零价铁活化过硫酸盐降解地下水中二恶烷

发布时间：2017-12-26 22:33

本文关键词：超声强化含铁矿石及零价铁活化过硫酸盐降解地下水中二恶烷　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：二恶烷(1,4-dioxane)被广泛应用于化工生产,在许多污染场地中均发现二恶烷的存在。二恶烷化学性质稳定,且由于其具有毒性,在环境中难以被生物降解。高级氧化法中,过硫酸盐氧化法是一种能够对难降解有机物具有高效降解能力的方法,且过硫酸盐氧化法已有在地下水中处理有机污染物的研究,但尚未有利用此方法降解地下水中二恶烷的报道。本论文选取黑云母、电气石、硫铁矿三种含铁矿石及零价铁(ZVI)作为活化过硫酸盐的材料,对其活化过硫酸盐降解二恶烷的能力进行对比,同时从物料添加和地下水中离子两个方面对影响二恶烷降解的因素进行研究,主要成果如下:首先,对四种材料在超声强化条件下活化过硫酸盐降解二恶烷的能力进行了初步对比实验,并对四种材料进行了表征分析。结果表明,在有无超声强化时硫铁矿和ZVI均能够应用于活化过硫酸盐降解二恶烷。黑云母和电气石无法向溶液中释放足量的铁离子,过硫酸盐不能够被充分活化产生SO_4~-,因此二恶烷的降解率均低于30%。硫铁矿的成分为FeS_2、铁氧化物及铁盐,其中FeS_2不仅能够还原溶液中的Fe~(3+)生成大量的Fe~(2+),同时还能够直接活化过硫酸盐,因此超声强化硫铁矿体系中二恶烷的降解率高达92.3%。超声强化ZVI体系的降解率也达到了93%。ZVI中主要成分为Fe0,以及ZVI表面形成的铁氧化物。充足的Fe0能够持续还原溶液中的Fe~(3+),使Fe~(2+)保持较高的浓度,从而使过硫酸盐充分的被活化。其次,研究了超声对硫铁矿和ZVI活化过硫酸盐降解二恶烷过程的影响。超声波能够显著提高二恶烷的降解率,尤其在硫铁矿系统中,超声的强化效果由74%提升至92.3%。对于ZVI系统,在超声波的冲击下,Fe0能够直接转化为Fe~(2+),同时对ZVI表面的冲击也增加了传质效率,提高溶液中Fe~(2+)浓度。对于硫铁矿系统,超声波能够使硫铁矿颗粒破碎,增大与溶液的接触面积,从而提高FeS_2参与反应的效率,增加Fe~(2+)浓度。此外,超声波本身也能够活化过硫酸盐,产生SO4·-。最后,研究了物料添加量和地下水中离子对二恶烷降解过程的影响。ZVI、硫铁矿投加量和过硫酸盐浓度的提高可以提高二恶烷的降解速率,高浓度CO_3~(2-)、Cl-离子浓度不利于二恶烷的降解。当Fe~(2+)相对过硫酸盐过多时,会出现Fe~(2+)抑制反应的现象,其原因主要是Fe~(2+)对SO4·-的竞争消耗,并且由于高效活化产生了大量的SO4·-未参与降解过程导致SO4·-的自我淬灭。CO_3~(2-)、Cl-离子均能够与SO4·-反应并生成氧化还原电位较低的CO3·-、Cl·,降低体系的氧化能力。此外,CO_3~(2-)还能够与溶液中的铁离子形成络合物或沉淀,降低铁离子浓度。
[Abstract]:Two oxane (1,4-dioxane) is widely used in chemical production, and the existence of two oxane is found in many polluted sites. The chemical properties of two oxane are stable, and because of their toxicity, it is difficult to be biodegraded in the environment. Advanced oxidation process, the persulfate oxidation method is a method to have high ability of degrading refractory organic compounds, and persulfate oxidation treatment of organic pollutants in the groundwater has been, but not by the method of degradation of groundwater in the dioxane two report. In this paper, tourmaline, biotite pyrite containing three kinds of iron ore and zero valent iron (ZVI) as the activated persulfate material, the activation ability of sulfate degradation of two dioxane were compared, and from two aspects of material addition and ion in the groundwater to study the influential factors of two dioxane degradation. The main results are as follows: firstly, a preliminary comparison experiment was carried out on the ability of four kinds of materials activated persulfate degradation of two dioxane in ultrasonic conditions, and four kinds of materials were characterized and analyzed. The results show that both pyrite and ZVI can be applied to the activated persulfate degradation of two oxane with or without ultrasonic enhancement. Biotite and tourmaline can not release enough iron ions to the solution, and persulfate can not be fully activated to produce SO_4~-, so the degradation rate of two oxane is less than 30%. Pyrite is composed of FeS_2, iron oxides and iron salts. FeS_2 can not only reduce Fe~ (3+) in solution, but also directly activate Fe~, which can also directly activate persulfate. Therefore, the degradation rate of two oxane in ultrasound enhanced pyrite system is as high as 92.3%. The degradation rate of ultrasonic enhanced ZVI system also reached 93%. The main component of ZVI is Fe0, and the iron oxide formed on the surface of ZVI. Sufficient Fe0 can continue to restore the Fe~ (3+) in the solution, so that the Fe~ (2+) is maintained at a high concentration, so that the persulfate is fully activated. Secondly, the effects of ultrasonic on the degradation of two oxane by pyrite and ZVI activated persulfate were studied. Ultrasound can significantly increase the degradation rate of two oxane, especially in the pyrite system. The enhancement effect of ultrasound is increased from 74% to 92.3%. For ZVI system, under the impact of ultrasonic wave, Fe0 can be directly transformed into Fe~ (2+), and the impact on the surface of ZVI also increases the mass transfer efficiency and improves the Fe~ (2+) concentration in the solution. For the pyrite system, ultrasound can break pyrite particles and increase the contact area with the solution, thereby improving the efficiency of FeS_2 participating in the reaction and increasing the concentration of Fe~ (2+). In addition, ultrasound itself can also activate persulfate, producing SO4 -. Finally, the effects of the amount of material added and the ions in the groundwater on the degradation of two oxane were studied. The increase of ZVI, pyrite dosage and persulfate concentration can increase the degradation rate of two oxane. The high concentration of CO_3~ (2-) and Cl- ion concentration are not conducive to the degradation of two oxane. When Fe~ (2+) is relatively excessive persulfate, Fe~ (2+) inhibition will happen. The main reason is the competitive consumption of Fe~ (2+) to SO4. The CO_3~ (2-) and Cl- ions can both react with SO4 - - and produce CO3, Cl, and lower oxidation reduction potential, which reduces the oxidation capacity of the system. In addition, CO_3~ (2-) can also form complex or precipitate with iron ions in the solution to reduce the concentration of iron ions.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X523

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