Abstract
This paper evaluates different flushing agents to enhance the efficiency of electrokinetic remediation of a manufactured gas plant (MGP) soil contaminated with polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Because of high concentrations, PAHs were of environmental concern and required to be removed to acceptable levels. Four flushing agents, which included two surfactants (3% Tween 80, and 5% Igepal CA-720), one cosolvent (20% n-Butylamine) and one cyclodextrin (10% hydroxypropyl-β-cyclodextrin or HPCD), were examined to enhance the solubilization of PAHs in the soil. Four electrokinetic experiments were conducted at 2.0 VDC/cm voltage gradient and 1.4 hydraulic gradient in order to assess the effectiveness of these flushing solutions for the removal of PAHs. Variables measured during the application of electric potential were electric current, electroosmotic flow, and contaminant removal from the soil. After the completion of each test, the soil was further examined for moisture content, pH, redox potential, electrical conductivity, and residual contaminant distribution. It is found that cosolvent increased the soil pH, while the surfactants and HPCD did not induce substantial change in the soil pH. The current densities fluctuated with time for all tests and remained less than 1 mA/cm 2. The current density for the test conducted with cosolvent was higher as compared to the tests conducted with surfactants and HPCD. Electroosmotic flow was the maximum with the cosolvent, while the lowest flow was observed with Tween 80 surfactant. Overall, Igepal CA-720 surfactant yielded the highest removal efficiency due to partial solubilization of PAHs, causing some PAHs to migrate towards the cathode. Heavy metals are found to be strongly adsorbed/ precipitated and showed negligible migration behavior in all the tests. Based on the contaminant mass remaining in the soil, it is apparent that further optimization of the electrokinetic system is required to improve PAH removal efficiency for the MGP soil.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
