Remediating ethylbenzene-contaminated clayey soil by a surfactant-aided electrokinetic (SAEK) process

Abstract

The objectives of this research are to investigate the remediation efficiency and electrokinetic behavior of ethylbenzene-contaminated clay by a surfactant-aided electrokinetic (SAEK) process under a potential gradient of 2 V cm −1. Experimental results indicated that the type of processing fluids played a key role in determining the removal performance of ethylbenzene from clay in the SAEK process. A mixed surfactant system consisted of 0.5% SDS and 2.0% PANNOX 110 showed the best performance of ethylbenzene removed in the SAEK system. The removal efficiency of ethylbenzene was determined to be 63–98% in SAEK system while only 40% was achieved in an electrokinetic system with tap water as processing fluid. It was found that ethylbenzene was accumulated in the vicinity of anode in an electrokinetic system with tap water as processing fluid. However, the concentration front of ethylbenzene was shifted toward cathode in the SAEK system. The electroosmotic permeability and power consumption were 0.17 × 10 −6–3.01 × 10 −6 cm 2 V −1 s −1 and 52–123 kW h m −3, respectively. The cost, including the expense of energy and surfactants, was estimated to be 5.15–12.65 USD m −3 for SAEK systems, which was 2.0–4.9 times greater than that in the system of electrokinetic alone (2.6 USD m −3). Nevertheless, by taking the remediation efficiency of ethylbenzene and the energy expenditure into account for the overall process performance evaluation, the system SAEK was still a cost-effective alternative treatment method.