Equilibrium composition and properties of soil solutions

Mean Activity Coefficients of Humic Acids as Physicochemical Characteristics of Their Behavior in Water Environment

“…The equilibria between organic matter and water are important mainly in water-saturated soils, in which they can affect the immobilization of pollutants as well as the transport of nutrients. − Active coefficients of the humic substances and solute can strongly influence these processes and has been the subject of several studies, ,− but the determination and analysis of activity coefficients of humic acids are really scarce. Collazo-Lopez et al determined the activity coefficients of nonpolar organic solutes in sedimentary organic matter and its different extractable fractions by means of gas chromatography.…”

“…They focused on the pH effect on sorption including the solute activity coefficients. Shoba and Sen’kov determined the activity coefficients and the chemical potentials of ions and minerals in different soils on the basis of the physicochemical simulations and the data on the composition of the water extracts and soil solutions. Shoba and Chudnenko , studied the ion-exchange properties of humic acids.…”

Flooding effect on mineralogical and geochemical changes in alkaline‐sodic soil system of northern Pantanal wetlands, Brazil

“…A detailed study of the solid and liquid phases of the soil is essential to distinguish clay minerals produced by contemporary weathering or precipitation by fluids from those resulting from past environmental settings and diagenesis, which are no longer in equilibrium with the soil solution (Al‐Droubi, Fritz, Gac, & Tardy, ; Humphries et al, ; Joeckel & Ang Clement, ; Shoba & Sen'kov, ). In the soil environment, the mineral transformations are driven by the meteoric waters, sometimes altering the mineral suites at very short distances (Barbiero et al, ; Oliveira Junior, de Freitas Melo, de Paula Souza, & da Rocha, ), providing indicators for environmental changes (Deocampo, ; Humphries et al, ; Pal, ), and usually involving the formation of interstratified clay minerals (Furquim et al, ; Furquim, Barbiero, et al, ; Furquim, Graham, et al, ).…”