模拟砷和锑在矿区还原微生物作用下的迁移变化及水力传导
发布时间：2018-09-08 06:37
【摘要】：As、Sb污染已成为世界性环境污染问题,它们的地球化学性质类似。本文主要依据矿区两种常见厌氧细菌(SRB和JF-5)在灰岩表面形成FeS膜层,增大吸附剂表面积和吸附性能,通过运用柱实验、批试验来研究As和Sb在FeS包覆灰岩中的迁移和竞争行为,探讨其吸附机理、包覆膜层的内部变化和包覆灰岩的溶解特征。此外,在柱实验内容中初步运用了CXTFIT插入excel解析CDE模型来拟合As、Sb的迁移行为。主要研究结论如下:1、生物FeS包覆灰岩吸附As、Sb的量与生物FeS包覆量不呈正比增长,吸附量的增加会随着包覆量的增长衰减。运用CXTFIT插入excel的CDE模型能够对As、Sb在包覆灰岩中的迁移行为很好的拟合,并得到设定参数Rλ=(1.00E+06,0.00E+00)。2、生物FeS对As、Sb的吸附速率、吸附量及占用吸附位的关系分别为:V_(As)V_(Sb)、Q_(As)Q_(Sb)、W_(As)W_(Sb)。相对于较短的吸附时间(24h),较长时间(48h)吸附的纯灰岩和FeS包覆灰岩对As的吸附量分别提高约1倍和3倍。3、As~(5+)和Sb~5在FeS包覆灰岩吸附过程中发生了还原作用,并且生物纳米FeS对As和Sb的吸附行为中存在化学吸附行为。4、FeS包覆灰岩溶解过程中,纯灰岩、包覆2d和包覆7d的pH分别为6.4、5.0、4.7。说明生物FeS包覆层能明显阻滞灰岩的溶解,并能使最终pH降低约1.5个单位。5、不同包覆层厚度对灰岩溶解的初始阻滞能力不同,包覆溶解1h的C1(包覆3天)和C2(包覆7天)pH分别为3和5,说明包覆层发育越厚对灰岩溶解的阻滞能力越强。6、根据Frick第一定律,生物FeS包覆灰岩的溶解模型可用公式n_(Ca,sol)=A t~(1/2)-n_(Ca,gyp)进行描述,并得出次生Ca矿物沉淀的量n_(Ca,gyp)值分别为nC_0=19.5、nC_1=11.3、nC_2=16.8。
[Abstract]:As,Sb pollution has become a worldwide environmental pollution problem, their geochemical properties are similar. In this paper, based on the formation of FeS film layer on limestone surface by two common anaerobic bacteria (SRB and JF-5) in mining area, the surface area and adsorption property of adsorbent are increased. The migration and competition behavior of As and Sb in FeS coated limestone are studied by using column experiment and batch test. The adsorption mechanism, the internal changes of the coating layer and the dissolution characteristics of the coated limestone are discussed. In addition, CXTFIT insertion excel analytic CDE model is used to fit the migration behavior of As,Sb in the column experiment. The main conclusions are as follows: (1) the amount of As,Sb adsorbed by biological FeS coated limestone does not increase in direct proportion to the amount of biofilm coated with FeS, but the amount of adsorption decreases with the increase of the amount of encapsulation. The migration behavior of As,Sb in the covered limestone can be fitted well by using the CDE model inserted with excel by CXTFIT, and the fixed parameter R 位 = (1.00E 066 0. 00E 00). 2. The adsorption rate, adsorption capacity and adsorption site of As,Sb by biological FeS are: v _ V _ V _ (Sb) Q _ (As) Q _ (Sb) W _ (As) W _ (Sb)., respectively, and the relation between the adsorption rate, adsorption capacity and adsorption site is: v _ V _ (As) _ V _ (Sb) Q _ (As) _ Q _ (Sb) W _ (As) W _ (Sb). Compared with the shorter adsorption time (24 h), the adsorption of As on pure limestone and FeS coated limestone at a longer time (48 h) increased by about 1 and 3 times, respectively, and the reduction of Sb~5 and As5 on the adsorption process of FeS coated limestone took place. In addition, the chemisorption behavior of As and Sb by biological nanometer FeS. 4FeS-coated limestone dissolved in pure limestone, the pH of 2d and 7d were 6.4N 5.00.4.7respectively. The results show that biological FeS cladding can obviously block the dissolution of limestone and reduce the final pH by about 1.5 units. The initial blocking ability of different coating thickness on limestone dissolution is different. The pH values of C1 (3 days) and C2 (7 days) of coating dissolution for 1 h are 3 and 5, respectively, which indicate that the thicker the cladding layer is, the stronger the retardation of limestone dissolution is. According to Frick's first law, The dissolution model of biogenic FeS coated limestone can be described by the formula n _ (Ca,sol) A t ~ (1 / 2) -n _ (Ca,gyp), and the quantity n _ (Ca,gyp) of secondary Ca mineral precipitation is obtained as nC_0=19.5,nC_1=11.3,nC_2=16.8..
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X172;X751
本文编号：2229667
[Abstract]:As,Sb pollution has become a worldwide environmental pollution problem, their geochemical properties are similar. In this paper, based on the formation of FeS film layer on limestone surface by two common anaerobic bacteria (SRB and JF-5) in mining area, the surface area and adsorption property of adsorbent are increased. The migration and competition behavior of As and Sb in FeS coated limestone are studied by using column experiment and batch test. The adsorption mechanism, the internal changes of the coating layer and the dissolution characteristics of the coated limestone are discussed. In addition, CXTFIT insertion excel analytic CDE model is used to fit the migration behavior of As,Sb in the column experiment. The main conclusions are as follows: (1) the amount of As,Sb adsorbed by biological FeS coated limestone does not increase in direct proportion to the amount of biofilm coated with FeS, but the amount of adsorption decreases with the increase of the amount of encapsulation. The migration behavior of As,Sb in the covered limestone can be fitted well by using the CDE model inserted with excel by CXTFIT, and the fixed parameter R 位 = (1.00E 066 0. 00E 00). 2. The adsorption rate, adsorption capacity and adsorption site of As,Sb by biological FeS are: v _ V _ V _ (Sb) Q _ (As) Q _ (Sb) W _ (As) W _ (Sb)., respectively, and the relation between the adsorption rate, adsorption capacity and adsorption site is: v _ V _ (As) _ V _ (Sb) Q _ (As) _ Q _ (Sb) W _ (As) W _ (Sb). Compared with the shorter adsorption time (24 h), the adsorption of As on pure limestone and FeS coated limestone at a longer time (48 h) increased by about 1 and 3 times, respectively, and the reduction of Sb~5 and As5 on the adsorption process of FeS coated limestone took place. In addition, the chemisorption behavior of As and Sb by biological nanometer FeS. 4FeS-coated limestone dissolved in pure limestone, the pH of 2d and 7d were 6.4N 5.00.4.7respectively. The results show that biological FeS cladding can obviously block the dissolution of limestone and reduce the final pH by about 1.5 units. The initial blocking ability of different coating thickness on limestone dissolution is different. The pH values of C1 (3 days) and C2 (7 days) of coating dissolution for 1 h are 3 and 5, respectively, which indicate that the thicker the cladding layer is, the stronger the retardation of limestone dissolution is. According to Frick's first law, The dissolution model of biogenic FeS coated limestone can be described by the formula n _ (Ca,sol) A t ~ (1 / 2) -n _ (Ca,gyp), and the quantity n _ (Ca,gyp) of secondary Ca mineral precipitation is obtained as nC_0=19.5,nC_1=11.3,nC_2=16.8..
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X172;X751
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