Physico‐chemical factors influencing ethyleneamine sorption to soil

摘要

AbstractBatch equilibrium studies were conducted with 1,2‐ethanediamine (EDA) andN‐(2‐aminoethyl)‐1,2‐ethanediamine (DETA) to examine the physico‐chemical factors that influence the sorption of the amines to soil. Sorption isotherms were generated using a variety of surface and subsurface soils. The results from this investigation demonstrated that, despite their miscibility in water, both EDA and DETA sorbed strongly to soil. The rate of sorption for both amines was fairly rapid, and equilibrium was achieved within several hours. Sorption isotherms could be best described by the Freundlich equation, and a series of Freundlich constants,Kd's, were developed for each soil and amine. Sorption of the ethyleneamines correlated closely with the cation exchange capacity (CEC) and organic content of the soil. Soils with increased CEC and organic content exhibited higher affinities for the amines. This dependence of sorption on CEC and organic content was most likely due to the strong electrostatic interaction between the positively charged amine and the negatively charged soil surface. For all soils DETA sorbed more strongly than EDA, although the sorption constants varied over an order of magnitude for both compounds. In order to decrease the variation observed in theKdvalues, the sorption constants were normalized to the organic carbon content of the soil and uniqueKocvalues were developed for each amine. The averageKocvalues for EDA and DETA were 4,766 and 19,111, r