Effects of Acid Precipitation on Composition, Electrokinetic Behavior, Cation Adsorption and Ion Exchange Capacity in Various Soil Systems

摘要

The effects of acidic environments on the physical/chemical behavior of natural soils from Tennessee was examined in the laboratory. Primarily, the influence of increased weathering of iron oxides on electrokinetic behavior, cation exchange capacity and adsorption of 'free' and complexed heavy metals was studied. Natural soils, compared to samples in which iron oxides were removed showed little change in cation exchange capacity or electrokinetic behavior. Acid aging of one particular soil was also conducted. Studies showed that prolonged exposure to acidic environments may result in drastic changes in soil properties. Substantial changes in the electrokinetic behavior were found with the zero point of charge increasing from a pH of 2.0 for the unaged soil to 8.0 for the acid aged one. Also, the zinc adsorptive behavior of the soils changed significantly with acid aging. The study indicates that prolonged exposure to acidic environments may create changes in physical/chemical properties of soils rich in iron oxides.