Copper removal from contaminated soil through electrokinetic process with reactive filter media

Area of Science:

• Environmental Science
• Soil Science
• Electrochemistry

Background:

• Electrokinetic (EK) remediation is a viable technique for removing metal ions from contaminated soils.
• Integrating EK with reactive filter media (RFM) can enhance contaminant removal efficiency.
• Copper contamination in soil poses significant environmental and health risks.

Purpose of the Study:

• To investigate the efficacy of integrating electrokinetic remediation with activated carbon (AC) and biochar (BC) as reactive filter media for copper ion removal from kaolinite soil.
• To compare the performance of EK, EK-AC, and EK-BC systems in copper removal.
• To assess the regeneration and recovery of copper from the RFM.

Main Methods:

• Electrokinetic remediation tests were conducted using EK alone, EK with AC (EK-AC), and EK with BC (EK-BC).
• Experiments were performed under a constant electric potential (10 V) and constant current (20 mA).
• Copper removal efficiency, capture by RFM, and copper recovery after acid leaching were quantified.

Main Results:

• EK-BC demonstrated higher overall copper removal efficiency compared to EK-AC and EK.
• Biochar captured 27% of soil copper under fixed voltage and 26% under constant current, significantly more than activated carbon (10%).
• EK-BC under constant current achieved 70.6-95.0% copper removal in specific soil sections, with 99.3% copper recovery from BC after acid leaching.

Conclusions:

• The integration of electrokinetic remediation with biochar as a reactive filter medium is a feasible and effective approach for copper-contaminated soil remediation.
• Biochar offers superior copper adsorption and recovery capabilities compared to activated carbon in EK systems.
• This method shows potential for sustainable soil remediation with efficient contaminant entrapment and recovery via acid leaching.