摘要:
本文研究了不同提取剂pH变化对从沉积物中释放金属浓度的影响.结果表明:沉积物中所释放的金属浓度随提取剂pH增加而减少,当pH为1.0时,相同的提取条件下,各种提取剂提取所获得的金属浓度相近.同时也研究了在所选择的提取液中沉积物对金属离子的吸附作用,发现沉积物对所加金属离子有明显的吸附作用.结果强烈地支持在实际对沉积物样品提取过程中存在着再吸附作用和提取剂的pH将对从沉积物中释放金属浓度起重要控制作用. 拟定了沉积物中三步连续提取的方法,即把沉积物金属结合态分为无机态(酸可提取态)、有机(包括硫化物)态和残渣态,并与Tessier的连续提取法进行比较.发现在非残渣态中二种方法的金属释放量类似,但三步连续提取法具有简单,快速和低消耗等优点.
Abstract:
The effect of pH of different leaching reagents on metal concentrations released was investigated in sediment. The results show that metal concentrations released decreased with increasing pH of leaching reagents and similar results were obtaiued using different leaching reagent at pH 1.0 under the same conditions.The adsorption of trace metals from selected extracted solutions onto the river sediment was also investigated. Significant adsorption of added metals was found. The results strougly support that the readsorption would occur during an actual extration from a sediment sample and pH of leaching reagents should have an important control over metal concentrations released in sedimentA three-step procedure, inorganic phase(or acid extractable phase), organic(including sulphide)phase and residual, was developed in sediment. The procedure was compared with Tessier's method. It was found that concentrations of trace metals released using two methods in non-residual phase draw near, but the new procedure has the advantages of being rapid, simple and lower in cost.
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