Laboratory investigation on solutes removal from artificial amended saline soil during the electrochemical treatment

Abstract

Soil salinity has become one of the environmental issues around the world, compromising thus land ecosystems as well as civil engineering infrastructures and facilities. This hazard is further aggravated, primarily when dealing with low permeable soils, where conventional remediation techniques are inadequate and mostly ineffective. Electrochemical treatment is an innovative and green technology for restoration of saline soils. This process has been proven to be the most efficient, promising technique, offering an optimal and sustainable remediation of salt-affected soils. The originality of this method involves application of an electric current through inserted electrodes into the soil matrix, inducing mobilization and transport of salts toward the electrodes of opposite charge via electro-migration process. The electrical current also induces a net water flow by electro-osmosis mechanism, allowing better draw and removal of solutes within the porous medium. This paper investigates the performance of the electrochemical treatment in remediation of salt-affected soil. Sodium, potassium and calcium were used as selective contaminants with targeted concentration of 0.5 M. In this aim, a laboratory bench scale was designed. It consists of soil box, anolyte and catholyte reservoirs, current monitoring devices, pH and electrical conductivity probe controller. The highest removal was for sodium and potassium with an extraction of 88 and 82%, respectively. Calcium exhibits lower removal rate of 57%, due to the development of the pH gradient, hindering therefore their mobility. This study demonstrated that electrochemical treatment can be advantageous in remediation of salt-affected soils, for enhancing agricultural productivity as well as soil constructional uses.