不同电子供体强化高氯酸盐自然衰减的柱实验研究

发布时间：2018-09-17 12:54

【摘要】：高氯酸盐(ClO_4~ )是一种小分子量、有毒的无机络阴离子,普遍存在于环境中。由于其分子大小与碘离子相似而干扰人体甲状腺的正常功能,因此其环境污染问题引起了广泛的关注。本文以ClO_4~ 为目标污染物,主要利用柱实验的研究方法,开展强化ClO_4~ 自然衰减的研究。模拟自然环境,考察了粒状铁、硫磺、松树皮分别作为电子供体强化ClO_4~ 自然衰减的可行性、持久性以及不同环境因素对强化过程的影响,为地下水环境中ClO_4~-原位修复的实际应用提供理论指导和数据支持。研究内容及成果如下:⑴在含水介质中,ClO_4~-自然衰减过程主要依靠微生物作用,但过程缓慢且还原量有限,长期的去除效果不超过10%,限制因素就是缺乏电子供体。⑵粒状铁、硫磺、松树皮均可以强化Cl O_4~-自然衰减,该强化过程微生物呈现很强的适应能力。根据氯元素平衡计算表明ClO_4~-几乎全部被还原为Cl-,没有其他氯代产物生成。⑶粒状铁强化的体系由于铁的钝化作用,长期去除率不超过70%;硫磺强化体系在缺乏地下水的阶段去除率不超过60%,通入地下水后去除率保持在100%;有机碳源松树皮强化体系,ClO_4~-去除率几乎都在100%,是一种比较理想的电子供体。⑷地下水环境中ClO_4~-和NO_3~-的还原存在竞争作用。当电子供体充足时,二者的竞争作用并不明显,均可以迅速的去除;当电子供体不足时,NO_3~-会优先于ClO_4~-的降解,只有NO_3~-低于10 mg/L时,ClO_4~-才开始明显的降解。⑸虽然地下水化学成分的部分阴离子对ClO_4~-的降解存在竞争作用,但地下水中的化学成分仍旧是ClO_4~-自然衰减的必要条件,对ClO_4~-自然衰减过程有促进作用。
[Abstract]:Perchlorate (ClO_4~) is a small molecular weight, toxic inorganic complex anion, which exists in the environment. Because its molecular size is similar to iodine ion, it interferes with the normal function of human thyroid. In this paper, the natural attenuation of ClO_4~ is studied by means of column experiment. The natural environment was simulated, and the feasibility of enhancing the natural attenuation of ClO_4~ with granular iron, sulfur and pine bark as electron donors was investigated, and the effects of different environmental factors on the enhancement process were also investigated. It provides theoretical guidance and data support for the application of ClO_4~- in situ remediation in groundwater environment. The contents and results of the study are as follows: 1 in aqueous medium, the natural decay process mainly depends on the action of microorganism, but the process is slow and the reduction amount is limited, the long-term removal effect is not more than 100.The limiting factor is the lack of the electron donor .2 granular iron, Sulfur and pine bark could enhance Cl O _ 4 attenuation, and the microbes showed strong adaptability. According to the equilibrium calculation of chlorine elements, almost all of ClO_4~- was reduced to Cl-, without any other chlorinated products to form the system strengthened by 3.3-grain iron due to the passivation of iron. The long-term removal rate is not more than 70; the removal rate of sulfur enhancement system is no more than 60 during the period of groundwater shortage, and the removal rate is kept at 100 after entering groundwater. The organic carbon source pine bark enhancement system has almost 100 removal rates, which is a comparative principle. The reduction of ClO_4~- and NO_3~- in the groundwater environment of electron donor 4. 4 is competitive. When the electron donor is sufficient, the competition between the two is not obvious and can be removed quickly. When the electron donor is insufficient, no _ 3s-will take precedence over the degradation of ClO_4~-. Only when the NO_3~- is less than 10 mg/L does the biodegradation begin to be obvious. Although some anions of the chemical constituents of groundwater compete for the degradation of ClO_4~-, the chemical composition in groundwater is still a necessary condition for the natural decay of ClO_4~-. It can promote the natural decay process of ClO_4~-.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X523

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