Competitive adsorption, release and speciation of heavy metals in the Yellow River sediments, China
Competitive adsorption, release and speciation of heavy metals in the Yellow River sediments, China
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DOI：
10.1007/s00254-007-0638-5
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发表时间：
2007-01
期刊：
影响因子：
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通讯作者：
Qing-yun Fan;Jiang He;Hongxi Xue;Changwei Lü;Ying Liang;Saruli;Ying Sun;Lili Shen
中科院分区：
文献类型：
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作者：
Qing-yun Fan;Jiang He;Hongxi Xue;Changwei Lü;Ying Liang;Saruli;Ying Sun;Lili Shen
研究了黄河底泥中部分重金属的竞争吸附和释放及其吸附前后的形态分布。沉积物对金属的吸附随pH值的增大而增大，随离子强度的增大而减小。得到的竞争系数Kc和分配系数Kdare用来分析所选重金属的竞争能力，排序为：铅、铜、锌、镉。随着水中离子浓度的增加，重金属之间的竞争变得更加激烈。形态分析是通过改进的分析程序进行的，包括五个步骤的顺序提取。在吸附过程中，铜、铅、锌主要转化为碳酸盐结合态(50.8-87.7%)。60.7-77.3%的Cd大部分转化为交换态，碳酸盐结合态Cd的比例为19.7-30.4%。释放反应如此之快，以至于选定的重金属从底泥到水溶液的释放容量仅在30℃时达到最大值的一半，而不是吸附，而选定的重金属的释放容量排序为Cd；；Zn；；>；>；；Cu2；>；>Pb.在本研究中，镉产生最严重的环境危害，因为它在释放液中的浓度是美国环保局人体健康标准的85.8倍。
The competitive adsorption and the release of selected heavy metals and their speciation distribution before and after adsorption in the Yellow River sediments are discussed. The adsorption of metals onto sediments increases with increasing pH value and decreases with increasing ionic strength. The competitive coefficientKcand the distribution coefficientKdare obtained to analyze the competitive abilities of selected heavy metals, which are ranked as Pb > Cu >> Zn > Cd. The competition among selected heavy metals becomes more impetuous with increasing ion concentration in water. Speciation analysis was done by an improved analytical procedure involving five steps of sequential extraction. Cu, Pb and Zn were mainly transformed into the carbonate-bound form (50.8–87.7%) in adsorption. Most of (60.7–77.3%) Cd was transformed into the exchangeable form, and the percentage of carbonate-bound Cd was 19.7–30.4%. The release reaction was so quick that the release capacity of selected heavy metals from sediments to aqueous solution reached half of the maximum value only in 30 s. As opposed to adsorption, the release capacities of selected heavy metals were ranked as Cd > Zn >> Cu > Pb. In this study, Cd produces the most severe environmental hazards, because its concentration in the release solution is 85.8 times more than the human health criteria of US EPA.