EFFECT OF PH, TEMPERATURE, AND CONCENTRATION ON THE ADSORPTION OF CADMIUM ON GOETHITE

被引:238
作者
JOHNSON, BB
机构
[1] Department of Biological and Chemical Sciences, Bendigo College of Advanced Education, Bendigo, Victoria
关键词
D O I
10.1021/es00071a014
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
Adsorption of cadmium onto goethite has been investigated as a function of both solution concentration and temperature. The pH range over which adsorption occurred was shifted to higher pH values as the initial cadmium concentration was increased and as the solution temperature was decreased. Over the temperature range studied (10–70 °C), the results of adsorption experiments carried out at pH 6.5 and 7.0 could be fitted by using a one-site Langmuir adsorption isotherm. However, at pH 7.5 a two-site Langmuir model was needed to fit the data. The integral heat of adsorption found from the Langmuir constants was ~ 13 kJ mol−1 at pH 6.5 and 7.0, while the two-site types at pH 7.5 yielded heats of adsorption of 20 and 6 kJ mol−1, respectively. The isosteric heat of adsorption was also determined and found to decrease with increasing surface coverage. © 1990, American Chemical Society. All rights reserved.
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页码:112 / 118
页数:7
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