Effects of organic acids on adsorption of lead onto montmorillonite, goethite and humic acid.
Effects of organic acids on adsorption of lead onto montmorillonite, goethite and humic acid.
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DOI：
10.1016/s0269-7491(02)00272-5
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发表时间：
2003-03
影响因子：
8.9
通讯作者：
Zhenghua Wu;Zhimang Gu;Xiaorong Wang;L. Evans;Hongyan Guo
中科院分区：
文献类型：
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作者：
Zhenghua Wu;Zhimang Gu;Xiaorong Wang;L. Evans;Hongyan Guo
研究了石英、长石、高岭石、蒙脱石、针铁矿和胡敏酸等6种土壤组分对铅的吸附等温线。考察了pH、EDTA和柠檬酸对蒙脱石、针铁矿和腐殖酸吸附铅的影响。结果表明，实验数据符合Langmuir吸附等温线。在pH 6时，腐殖酸对Pb的吸附量为22.7 mg g−1>针铁矿（11.04 mg g−1）>蒙脱石（10.4 mg g − 1）>高岭石（0.91 mg g−1）>长石（0.503 mg g−1）>石英（0.148 mg g−1）。一般来说，吸附到蒙脱石，针铁矿和腐殖酸的铅的量减少与EDTA和柠檬酸的浓度增加，并与碱性的增加。然而，有两个例外：（1）柠檬酸的加入增加了吸附到腐殖酸上的Pb的量;和（2）在EDTA存在下，随着pH的增加，吸附到针铁矿上的Pb的量减少。讨论了吸附反应的机理。
Adsorption isotherms for Pb onto six soil components (quartz, feldspar, kaolinite, montmorillonite, goethite and humic acid) were studied. The influence of pH, EDTA and citric acid on the adsorption of Pb onto montmorillonite, goethite and humic acid were considered. Results indicate that the experimental data fit the Langmuir Adsorption Isotherm. The adsorption capacity for Pb at pH 6 was found to be in the order: humic acid (22.7 mg g−1)>goethite (11.04 mg g−1)>montmorillonite (10.4 mg g−1)>kaolinite (0.91mg g−1)>feldspar (0.503 mg g−1)>quartz (0.148 mg g−1). Generally, the amount of Pb adsorbed onto montmorillonite, goethite and humic acid decreased with increasing concentrations of EDTA and citric acid and with increases in alkality. However, there were two exceptions: (1) addition of citric acid increased the amount of Pb adsorbed onto humic acid; and (2) the amount of Pb adsorbed onto goethite decreased with increasing pH in the presence of EDTA. Some mechanisms involved in the adsorption reactions are discussed.