Co~(2+) sorption capacity indicators of La Plata region's soils: insights and correlations with soil properties

摘要

Notwithstanding that the soil acts as a pollutant sink, its Co sorption capacity presents still controversial results. Here, Co~(2+)sorption on soil samples from La Plata (Argentina) was analysed. Four sorption indicators were used: K_(dis)(estimated from the entire sorption isotherm), K_(F1)(estimated from the lineal part of the sorption isotherm), K_(dx), (solid-solution distribution coefficient) and K_(r), a dimensionless parameter recently developed. Pearson correlation coefficients between the parameters and soil properties were calculated. Significant and negative correlations with silt were obtained, whereas significant and positive correlations were established with clay and smectite content. Soil clay fractions were isolated and Co~(2+)sorption was evaluated, observing relatively high removal. The correlations with kaolinite, magnetite and Mn and Fe oxides showed debatable results: K_(dis)could be more sensitive than K_(r)to magnetite variations whereas K_(r)seems to be more sensitive to Mn changes. K_(F1)presented similar behaviour to K_(r). The studied soils presented a high Co~(2+)sorption capacity, making them an effective barrier of this pollutant, avoiding its passage to groundwater and crops.