Effect of cropping systems on adsorption of metals by soils: II. Effect of pH

Journal Article · Sun Mar 01 04:00:00 EST 1992 · Soil Science; (United States)

DOI:https://doi.org/10.1097/00010694-199203000-00004· OSTI ID:7045532

Basta, N T; Tabatabai, M A ^[1]

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1. Iowa State Univ., Ames (United States)

The effect of pH on adsorption of Cd, Cu, Ni, Pb, and Zn by soils under different cropping systems was investigated. Plots of metal adsorption vs. pH (unadjusted) were generated for 24 soils, 12 from each of two long-term cropping systems. Two soils, one from each site, were selected to study the metal adsorption over a range of adjusted pH values. Results showed that differences in metal adsorption were dependent on the initial heavy-metal concentration. Although some of the adsorption behavior of these metals was consistent with that based on meal hydrolysis, other results showed that this mechanism could not explain metal adsorption. Metal distribution coefficients, K{sub d}, decreased sharply with increasing initial metal concentration and followed the sequence: Pb {ge} Cu >> Cd = Ni = Zn. Also, K{sub d} values were related to solution pH. At high solution pH, part of the Pb and Cu adsorption could be explained by adsorption of hydroxocomplexes from hydrolysis reactions of these metals. Plots of K{sub d} vs. initial metal concentration suggested that Cd, Ni, and Zn adsorption could be attributed to ion-exchange reactions.

• OSTI ID: 7045532
• Journal Information: Soil Science; (United States), Journal Name: Soil Science; (United States) Vol. 153:3; ISSN SOSCA; ISSN 0038-075X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION
AGRICULTURE
CADMIUM
CHEMICAL REACTIONS
COPPER
CROPS
CULTIVATION TECHNIQUES
DECOMPOSITION
ELEMENTS
HYDROLYSIS
ION EXCHANGE
LEAD
LYSIS
METALS
NICKEL
PH VALUE
SOILS
SOLVOLYSIS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TRANSITION ELEMENTS
ZINC