Sodic-saline soil remediation by electrochemical treatment under uncontrolled pH conditions

Abstract

Sodic and saline soils are found mainly in regions with weak precipitations such as areas where aridity predominates. The low rainfall rate causes salt accumulation at high level on the soil surfaces affecting hence both the environment and foundations of constructions and buildings. This study is aimed to investigate the performance and the potential of electrochemical treatment for decontamination of sodic-saline soil. For this purpose, soil specimens were collected from the region of Mostaganem located in the north-western of Algeria, which is classified as semi-arid zone. In this region, many large areas are greatly affected by salinity phenomenon during recent years. Seven indices including electric current, electro-osmotic flow, pH, electrical conductivity (EC), exchangeable sodium adsorption ratio (ESP), sodium adsorption ratio (SAR), and salt removal efficiency including sodium, potassium, and calcium were explored. Experimental tests were conducted in laboratory-designed cell using an electric potential difference of 15, 25, 35, and 45 V, respectively, for a total period of 7 days. Salts such as sodium (Na+), potassium (K+), and calcium (Ca2+) migrated and moved toward the catholyte chamber and accumulated there, by electro-migration and electro-osmotic mechanisms. Among these ionic compounds, the highest decontamination efficiency was achieved for Na+ and K+ ions estimated of 88% and 85%, respectively. However, for Ca2+ ions, the extraction rate was moderate than monovalent ions with a percentage of 59%. Our results demonstrated that the electrochemical treatment may be a simple, low-cost, and efficient alternative to decontaminate and remediate saline soils.