Effect of soil electroosmotic flow enhancement by chelating reagents

A new effect of a complexant enhanced electroosmotic how (EF) in clayey soi ls is described and interpreted. It is demonstrated that common chelating a gents (Citric acid, EDTA, HEDPA) are capable of providing one order of magn itude increase in flow intensity. The intensity of EF depends on the charac ter, concentration and pH of complexant solution, the character of soil and the voltage applied. EF passes maximum when HEDPA concentration changes fr om 0 to 0.8 M. It decreases at low pH of complexant solutions in comparison with high pH range. An observed ability of complexants to affect electroos mosis evidently offers a possibility of governing remediation technologies and to provide controlled delivery of nutrients to plant roots by an approp riate choice of the reagent, its concentration, and pH. (C) 1999 Elsevier S cience B.V. All rights reserved.