Soil Science · 1988 · 36 citations · 0 references
AgricultureEarth SciencesSoil SciencesSoil ChemistrySoil Organic MatterSoil ScienceMineral-organic InteractionsSoil AciditySoil AlkalinitySoil Chemical PropertiesSoil GeochemistrySoil PhBatch Ion ExchangeCarboxylate AnionsCation Exchange EquilibriaCation Exchange EquilibriumChemical EquilibrationSoil Cation Exchange Capacity
We conducted batch equilibration ion exchange experiments to determine selectivity of peat for various alkaline earth ions with calcium as the resident cation. Two levels of Ca-neutralized peat (100 and 33%) were prepared from acid-washed samples (CEC = 2.72 mol(+) kg−1) by equilibration with equivalent amounts of CO2-free saturated Ca(OH)2. The pH and concentrations of Ca2+ and the exchanging ion were determined at the end of each equilibration period. Both the 100 and 33% Ca-neutralized peat showed the preferential sequence Mg<Sr<Ca<Ba. Considering the Eisenman model, we suggest that this exchange behavior is due to the widely separated fixed carboxylate sites. The formation of (RCOO Me)+ ion pairs is thus suggested to predominate in such systems.