Description
A COMPOSITE REACTIVE FILTER MEDIA FOR HEAVY METALS REMOVAL FROM SOIL BY ELECTROKINETIC PROCESS (remote evaluation)Electrokinetic (EK) is an effective technique for electrochemical remediation of low permeability soils. It involves applying a low-intensity direct current to mobilize soluble chemical species and soil pore solution. EK has been proposed for in-situ soil remediation to reduce excavation and hazardous exposure. However, the precipitation of heavy metals near the cathode in alkaline conditions remains a challenge. To enhance heavy metal removal, reactive filter media (RFM) and enhancement agents are employed, facilitating
adsorption and resource recovery.
This study explored combining industrial iron slag waste with organic waste materials (activated carbon, tea waste, and sawdust) as RFMs to improve the performance of the EK process. Iron slag offers high heavy metal adsorption but struggles to control alkaline pH near the cathode. Blending iron slag with organic materials improved metal ions adsorption and pH control while recycling the anolyte solution eliminated the need for acids to neutralize the cathode’s alkaline front.
Experiments conducted at 20 mA for 2-3 weeks demonstrated that coupling iron slag activated carbon RFMs with EK increased copper removal from 3.11% to 23%, reaching 93.45% with anolyte recirculation and longer treatment. Testing a mixture of heavy metals showed 81.1% copper, 89.04% nickel, and 92.31% zinc removal after 3 weeks. Enhanced nickel and zinc removal was attributed to higher solubility compared to copper. Recyclable RFMs composed of powder iron slag/black tea waste (PIS/BTW) and granular iron slag/black tea waste (GIS/BTW) were tested. PIS/BTW outperformed GIS/BTW, achieving 98.75% copper removal versus 90.06%. For a heavy metals mixture in kaolinite soil, copper, nickel, and zinc removal reached 97.15%, 98.30%, and 96.68% after 4
weeks, while natural soil results were lower due to environmental complexity.
Additionally, incorporating sawdust crosslinked with glutaraldehyde and iron slag into RFMs improved copper removal, achieving 97.92% in kaolinite soil at 0.18 kWh/kg specific energy. In natural soil, copper, nickel, and zinc removal reached 26.72%, 54.36%, and 56.44% after 5 weeks. The variability between kaolinite and natural soils highlights the challenges of applying laboratory findings to field conditions. This dissertation demonstrates that eco-friendly, recyclable RFMs can significantly optimize EK remediation, offering a sustainable solution for heavy metal contamination in soils.
| Period | 3 Jun 2025 |
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| Examinee | Faris Hamdi |
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| Degree of Recognition | International |