Pedosphere 3(2): 161--172, 1993
ISSN 1002-0160/CN 32-1315/P
©1993 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Adsorption Kinetics of Pb2+ and Cu2+ on Variable Charge Soils and Minerals: Ⅱ. Equations for Describing Experimental Data |
| HU GUO-SONG |
| Institute of Soil Science, A cademia Sinica, P. O. Box 821, Nanjing 210008 |
| ABSTRACT |
| Different mathematical methods, including linearization, differential, integration and nonlinear least squares approximation (Newton-Marquardt method), were used to fit different kinetic equations, such as zero-order, first-order (i. e, membrane diffusion), second-order, parabolic-diffusion, Elovich, two-constant equations, to the experimental data of Pb2+ and Cu2+ adsorption on variable charge soils and kaolinite. Assuming each M2+ occupied two adsorption sites, two more equations, the so-called surface second-order equation and third-order equation were derived and compared with the above equations according to the fitting results, which showed that the second-order equation and surface second-order equation, being one equation in different expressions under some conditions, were better than the other equations in describing the Pb2+ and Cu2+ adsorption kinetics, and the latter was the best. |
| Key Words: |
| Citation: Hu, G. S. 1993. Adsorption Kinetics of Pb2+ and Cu2+ on Variable Charge Soils and Minerals: Ⅱ. Equations for Describing Experimental Data. Pedosphere. 3(2): 161-172. |
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