Ionicity of clay-cation bonds in relation to dispersive behavior of Mg and K soil clays as influenced by pH
Article
Article Title | Ionicity of clay-cation bonds in relation to dispersive behavior of Mg and K soil clays as influenced by pH |
---|---|
ERA Journal ID | 1716 |
Article Category | Article |
Authors | Zhu, Yingcan (Author), Marchuk, Alla (Author) and Bennett, John McLean (Author) |
Journal Title | Clays and Clay Minerals |
Number of Pages | 13 |
Year | 2020 |
Place of Publication | Switzerland |
ISSN | 0009-8604 |
1552-8367 | |
Digital Object Identifier (DOI) | https://doi.org/10.1007/s42860-020-00100-x |
Web Address (URL) | https://link.springer.com/article/10.1007%2Fs42860-020-00100-x |
Abstract | The dispersive behavior dynamics of clay determine soil characteristics such as permeability and aggregate stability, and, consequently, crop productivity. Soil dispersion is heavily influenced by the ionicity of clay–cation bonds and has been shown to be related to the net negative charge and pH of the system. Little work has been done, however, which considers these factors together, especially for K and Mg clays. The objective of the present study was to investigate the effect of changing pH on the dispersive behavior of Mg and K homoionic clays, in comparison to Ca and Na clays under equivalent pH conditions. The clay fractions used here were extracted from three soils and have distinctly different mineralogies. These clays were treated to become homoionic with regard to Na, K, Ca, and Mg. Excess salts were removed by dialysis and pH was adjusted to 3, 4, 5, 6, 7, 8, 9, 10, and 11 for all clays, except Mg (pH range 3–7). Clay dispersion-flocculation dynamics were investigated, and the net negative charge, pH, electrical conductivity (EC), and turbidity were measured. Mg has a similar but less flocculative effect than Ca, while K has a similar but less dispersive effect than Na, under similar pH conditions. The dispersive behavior of Na, K, Mg, and Ca homoionic clays was correlated well with the ionicity of clay–cation bonds at equivalent pH, with the degree of clay dispersion being explained by the pH, EC, ionicity, ζ-potential, and mean particle size of the clay–cation system. A predictive model for dispersion was developed with its applicability and limitations discussed. |
Keywords | Clay dispersion; Clay mineralogy; Exchangeable cations; pH; Zeta potential |
ANZSRC Field of Research 2020 | 300299. Agriculture, land and farm management not elsewhere classified |
300210. Sustainable agricultural development | |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Centre for Sustainable Agricultural Systems |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q600w/ionicity-of-clay-cation-bonds-in-relation-to-dispersive-behavior-of-mg-and-k-soil-clays-as-influenced-by-ph
174
total views10
total downloads3
views this month0
downloads this month