Removal of lindane using electrokinetic soil flushing coupled with air stripping

Abstract

This paper evaluates the remediation of soil spiked with lindane using a combined treatment consisting of electrokinetic soil flushing (EKSF) with air stripping to elucidate the main processes occurring in the soil when electric fields of 0.75 V cm−1 and 1.50 V cm−1 are applied. The results demonstrate that lindane is efficiently transported to the anodic and cathodic wells using flushing fluids containing sodium dodecyl sulfate (SDS). Additionally, an important amount is volatilized and stripped with the injected air. In the cathodic well, lindane is rapidly transformed into other species because of the strongly alkaline media. These other species are also found in the portions of soil next to this well, confirming the efficient transport of chlorinated organics with SDS. After 14 days of operation, nearly 50% of the spiked lindane can be removed from the soil. Operation with large electric fields does not improve the performance of the treatment technology and results in lower current intensities and electro-osmotic fluxes and in higher evaporated water, despite the water content in the soil matrix, indicating the coexistence of multiple inputs in these processes. Graphical abstract

Combining Soil Vapor Extraction and Electrokinetics for the Removal of Hexachlorocyclohexanes from Soil

“…The electric current produced is not proportional to the electric gradient but conversely, it is lower for the higher electric gradient, what initially was unexpected. Similar results were obtained in a previous work of de Melo Henrique et al, [10] which investigated the remediation of soil spiked with lindane using air stripping associated and electrokinetic soil flushing applied different electric fields (0.75 V cm À 1 and 1.50 V cm À 1 ) during 14 days. In this previous work, it was observed that the accumulated charge was higher for the electric field of 0.75 V cm À 1 .…”