Ion Exchange in Soils

Equilibrium Exchange Constants Evaluated by Different Methods 

Exchange Calculated by Argensinger Method k n Argensinger method Rothmund- Kornfeld method 

ion retention and exchange by charged soil colloids is important for plant nutrient retention and has many environmental implications as an example, NOj is important for plant growth, but if it leaches, it will move below the plant root zone and leach into groundwater, where it is deleterious to human health. If a soil has a significant anion exchange capacity, nitrate can be held so it is available to plants. 

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BunzI, K. (1974b). Kinetics of ion exchange in soil organic matter. III. Differential ion exchange reactions of Pb2+ -ions in humic acid and peat.. /. Soil Sci. 25, 517-532. 

It was Thomson [26], in 1845, who first performed a scientific study of ion exchange in soils. Almost, at the same time, Way [27] showed that the effect was related to aluminosilicates present in soils. Later, Lemberg and Wiegner [28,29] identified zeolites, clays, and other minerals as the aluminosilicates responsible for ion exchange in soils. Moreover, Eichorn [30], for the first time, studied ion exchange quantitatively, showing the reversibility of the reaction in some natural zeolites, such as chabazite and natrolite. 

Finally, when using search engines we advise you to use a variety of search options. Advanced search options that search for exact word strings are better for finding specific factual sites, whereas wider, less-constrained searches, usually find more diverse sites. Be as specific as you can. For example, if you are interested in ion exchange in soils use the phrase ion exchange soil rather than ion exchange . This will help you home in to the subject of interest much more efficiently. 

It must also be recognized that, because of the usually much finer subdivision of natural ion exchangers in soils as compared with commercial synthetic resins, surface phenomena may play a more prominent role. Among these effects are water is more structured at the interface than in the bulk liquid ions and water molecules are less mobile at the interface because of stronger interactions the dielectric constant of water is lower than in the bulk solution and surface charges produce an electric double layer (Horst, 1990). 

Bunzl, K. 1978. Kinetics of ion exchange in polydisperse systems. Anal. Chem. 50 258-267. Bunzl, K., W. Schmidt, and B. Sansoni. 1976a. Kinetics of ion exchange in soil organic matter. 

Most experiments on chemical weathering have been performed on pure minerals under carefully controlled laboratory conditions. However, under natural conditions in the field, mixtures of minerals of different abundances are reacting simultaneously, together with amorphous material and organic material subject to ion exchange in soils and sediments. It is instructive to conduct experiments on natural soils in the laboratory and then to compare these results with small plot experiments in the field and the prototype watershed. The site of Bear Brook Watershed at Lead Mountain, Maine (latitude 44 51 75", longitude 68 6 25") is shown in Figure 8. It contains two almost... 

Cans, at the turn of the 19lh century, synthesised aluminosilicate materials capable of water softening. He called them Permutits and for many years they were employed as domestic and industrial water softeners, as well as in the treatment of nuclear waste. This, together with the first identification of base exchange in soils (Way [2] and Thompson [3 J), led to the misunderstandings perpetuated in elementary texts that zeolites are responsible for the ion-exchange in soils, and that they are widely used as water softeners. In truth the clay minerals contribute mainly to the ability of soils to take up cations, such as ammonium, and Permutits were amorphous materials with low cation exchange capacities and limited chemical stability. 

Phosphate ion exchange in soils In soils, phosphate and other ion exchange processes occur on the surfaces of the solid phases (clay minerals, organic matter, and mineral surfaces). Ion exchange reactions are important for maintaining an equilibrium between the solid phase and the solution (soil pore water). Thus, it is important that we understand the origin of surface charge of the solid phase. 

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