| 查看: 191 | 回复: 0 | ||
[求助]
这段摘要求大神帮个忙翻一下
|
|
Abstract The apparent diffusivities (Da) for selenium (Se) in compacted bentonite were obtained at a dry density of 1.6 mg/m3 as a function of silica sand content and temperature under reducing conditions, in which the dominant species of Se is predicted to be HSe (hydroselenide) and were compared with Da values obtained under anaerobic conditions, in which the dominant species of Se is predicted to be SeO32- (selenite). The experiments were carried out by an in-diffusion method and a Na bentonite, Kunigel-V1R with Na smectite content of 46–49 wt.%, was used in a series of diffusion experiments. All diffusion experiments were carried out in a controlled N2 atmosphere glove box. The effects of silica sand content and temperature on Da are altogether summarized as follows: (1) The Da values show a tendency to increase with increasing silica sand content. (2) The Da values show a tendency to increase with increasing temperature. (3) The increasing rate of Da with temperature is approximately constant, independent of silica sand content. The Da values for HSe are about one order of magnitude smaller than those for SeO32- . This trend is consistent with that of distribution coefficients obtained by batch method. The Da values for HSe were well correlative with smectite partial density for both temperatures. This indicates that Se diffusion, including retardation processes, is predominantly controlled by the properties in part of smectite. The calculated activation energies for diffusion in the porewater [DEa(porewater)] were in the range of 17.6–31.6 kJ/mol and were slightly higher than that of ionic diffusivity in free water [DEa(free water) = 15.3 kJ/mol] for HS, which takes the same species as HSe in solution. Furthermore, the relative partial molar activation energies [DEa (relative)] calculated from DEa(free water) and DEa(porewater) values were in the range of 16.2 to 2.2 kJ/mol. A reason might be that the properties of the porewater of compacted bentonite are different from that of free water.  11.png |
回复此楼» 猜你喜欢
职称评审没过，求安慰
已经有41人回复
-
回收溶剂求助
已经有7人回复
-
硝基苯如何除去
已经有3人回复
-
A期刊撤稿
已经有4人回复
-
垃圾破二本职称评审标准
已经有17人回复
-
投稿Elsevier的Neoplasia杂志，到最后选publishing options时页面空白，不能完成投稿
已经有22人回复
-
EST投稿状态问题
已经有7人回复
-
毕业后当辅导员了，天天各种学生超烦
已经有4人回复
-
求助文献
已经有3人回复
-
三无产品还有机会吗
已经有6人回复