| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
a Faculty of Agriculture, Kochi Univ., B 200 Monobe, Nankoku 783-8502, Kochi, Japan
b United Graduate School of Agricultural Science, Ehime Univ., Matsuyama 790-8566, Japan
* Corresponding author (sahajp2001{at}yahoo.com)
We examined the adsorption behavior of Cd, Zn, and Pb from mixed solutions on synthetically prepared Hydroxyaluminum (HyA)- and Hydroxyaluminosilicate (HAS)-montmorillonite (Mt) complexes within the pH range 4 to 8. Initial concentrations of each metal (MeI) of 1 x 10-6 M in binary systems and 1 x 10-6, 2 x 10-5, 5 x 10-5 M in ternary systems were used in a background electrolyte of 0.01 M NaClO4. The presence of HyA and HAS polymers on Mt greatly increased the adsorption of all three metals. Lead appeared to have the strongest affinity for adsorption on both Mt and on the complexes. The adsorption affinity sequence of Pb > Cd > Zn on Mt did not change with MeI and could be explained with hard-soft acid-base (HSAB) theory. On the complexes, the affinity sequences of Zn > Cd in binary systems and Pb >> Zn 
Cd in most ternary systems were consistent with predictions based on the first hydrolysis constants. We propose that HyA-Mt and HAS-Mt are composed of nonuniform metal adsorption sites. For a given type of site, metal selectivity was predominantly determined by the metal properties, softness and ease of hydrolysis, while ionic potential had a limited predictive index for metal adsorption. The overall adsorption behavior of the metals along with their extraction patterns showed that the strength of adsorption followed the order of Pb >> Zn > Cd among the metals and of HyA-Mt HAS-Mt >> Mt among the adsorbents.
Abbreviations: CEC, cation-exchange capacity • CM, competing metal • ESR, electron spin resonance • HAS, hydroxyaluminosilicate • HSAB, hard-soft acid base • HyA, hydroxyaluminum • ICP–AES, inductively coupled plasma-atomic emission spectrometry • IAP, ion activity product • Me, metal • MeI, initial concentration of each metal • Mt, montmorillonite • PM, primary metal • PZSE, point zero salt effect • SA, strongly adsorbed • TA, total adsorbed • WA, weakly adsorbed • XRD, x-ray diffraction
This article has been cited by other articles:
|
|
 |
|
  U. K. Saha, L. M. Kozak, and P. M. Huang KINETICS OF CITRATE-INDUCED SELENITE DESORPTION FROM MONTMORILLONITE AS AFFECTED BY COMPLEXATION WITH HYDROXYALUMINUM AND HYDROXYALUMINOSILICATE IONS Clays and Clay Minerals, February 1, 2007; 55(1): 71 - 88. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Antoniadis, J. D. McKinley, and W. Y. W. Zuhairi Single-Element and Competitive Metal Mobility Measured with Column Infiltration and Batch Tests J. Environ. Qual., January 9, 2007; 36(1): 53 - 60. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 U. K. Saha, C. Liu, L. M. Kozak, and P. M. Huang Kinetics of Selenite Adsorption on Hydroxyaluminum- and Hydroxyaluminosilicate-Montmorillonite Complexes Soil Sci. Soc. Am. J., July 1, 2004; 68(4): 1197 - 1209. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. K. Saha, U. K. Saha, K. Iwasaki, and K. Sakurai DESORPTION BEHAVIOR OF Cd, Zn AND Pb SORBED ON HYDROXYALUMINUM-AND HYDROXYALUMINOSILICATE-MONTMORILLONITE COMPLEXES Clays and Clay Minerals, October 1, 2003; 51(5): 481 - 492. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Vadose Zone Journal | Journal of Plant Registrations | ||||
| Journal of Natural Resources and Life Sciences Education |
Journal of Environmental Quality |
||||
