Electrokinetic Flushing of Diesel-Contaminated Saturated Sand Using Surfactant-Enhanced Catholyte Solution

Abstract

Diesel contamination in saturated sandy soils and subsurface environments presents serious environmental challenges due to the low solubility and persistent nature of hydrocarbon pollutants. This study investigates the electrokinetic flushing of diesel-contaminated saturated sand using a surfactant-enhanced catholyte solution to improve contaminant mobilization and removal efficiency. The research focuses on evaluating the combined effects of electrokinetic transport and surfactant-assisted solubilization under controlled remediation conditions. Experimental analyses were conducted to examine the influence of applied voltage gradient, surfactant concentration, treatment duration, electrolyte composition, soil moisture content, and electrode configuration on diesel removal performance and contaminant migration behavior. Results demonstrated that the surfactant-enhanced catholyte significantly improved hydrocarbon desorption and transport by increasing diesel solubility and reducing interfacial tension between contaminants and soil particles. The electrokinetic process effectively promoted electromigration, electroosmosis, and electrophoretic transport mechanisms, leading to enhanced contaminant displacement toward the collection zones. Optimized operating conditions resulted in substantial reduction of diesel concentration in saturated sand with improved remediation efficiency compared to conventional flushing techniques. Kinetic evaluation revealed that contaminant transport behavior is strongly influenced by electric field intensity, surfactant distribution, and pore water conductivity.