Removal of chlorsulfuron and 2,4-D from spiked soil using reversible electrokinetic adsorption barriers

This work focuses on the application of REKAB (Reversible Electrokinetic Adsorption Barriers) technology to remediate two soil matrixes spiked with 2,4 dichlorophenoxyacetic acid (2,4-D) and chlorsulfuron (CLSF), two herbicides that exhibit a high water-solubility and very different volatility and adsorption properties (2,4-D is more volatile). Results obtained after 15-day treatment tests are compared with those obtained using single electrokinetic soil flushing technology (EKSF) and very important differences were pointed out. Both technologies are efficient in the removal of herbicides from soils. However, while in the EKSF, transport of pesticides to electrode wells is very important and evaporation is favored, in particular for the removal of 2,4-D, in the case of REKAB, retention by the carbon bed is the primary mechanisms (40% and 60% of 2,4-D and CLSF respectively) and both, evaporation and transport to electrode wells, although significant, are less important than in the EKSF. After the 15 day-treatment only 28% of 2,4-D and 12% of CLSF remained in the soil as pollutants and evaporation loses are less than half than those obtained in the EKSF technology.