δ-MnO_2降低无机三价砷毒性的研究

Decreased Toxicity Study of Inorganic Arsenite by δ-MnO_2

文章利用自制的δ-MnO2对剧毒性无机A(sⅢ)进行了氧化吸附过程的实验室研究,考察了反应进程中各形态砷的变化,同时进一步对与高浓度A(sⅢ)反应前后δ-MnO2的结构和形貌进行了X射线衍射(XRD)、扫描电子显微镜(SEM)和拉曼光谱(Raman)鉴定。实验结果表明,δ-MnO2通过氧化和吸附作用对A(sⅢ)的毒性去除效果显著,60 min内溶液中A(sⅢ)消失了72.3%。形态学研究表明,反应前后δ-MnO2的XRD图没有明显变化;而SEM图显示,反应后δ-MnO2的蜂窝状结构其固体孔隙比反应之前明显变小;EDX的数据显示δ-MnO2固体中出现了一定含量的As元素;δ-MnO2反应前后Raman光谱的吸收强峰由649 cm-1处变化到865 cm-1处,也表明出现了一部分可以永久固定在δ-MnO2固体内的A(sV)。该研究认为,δ-MnO2具有较强氧化和吸附活性,可以大大降低三价无机砷的毒性。

The synthesized δ-MnO2was used to oxidize and adsorb high toxicity in the lab, in order to review the concentration of As（ Ⅲ）and As（Ⅴ）during the reaction withδ-MnO2 Furthermore, the X ray diffraction（XRD）, the scanning electron microscope analysis（SEM）and the Raman spectra（Raman）were also used to compare the modality of δ-MnO2 before and after the reaction with the thick As（Ⅲ ）solution. The results demonstrated the prominent detoxication characteristic of the δ-MnO2 and 72.3% As（ Ⅲ ） was eliminated in 60minutes in the solution. On the modality study, the XRD of δ-MnO2 showed the crystal types nearly unchanged, the SEM photographs illustrated the distinct changes of the surface structure, and the EDX data indicated that the appearance of As inδ-MnO2 Otherwise, Raman spectroscopy showed that the main spectrum intensity of δ-MnO2 changed from 649 cm-1 to 865 cm-1, which demonstrated the generated As（Ⅳ） was fixed in the solid. In conclusion, the strong oxidative and adsorptive δ-MnO2can reduce the toxicity of inorganic As（ Ⅱ ） to a great extent.