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Hamdi FM, Altaee A, Alsaka L, Ibrar I, Al-Ejji M, Zhou J, Samal AK, Hawari AH. Iron slag/activated carbon-electrokinetic system with anolyte recycling for single and mixture heavy metals remediation. Sci Total Environ 2024; 930:172516. [PMID: 38636874 DOI: 10.1016/j.scitotenv.2024.172516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 04/02/2024] [Accepted: 04/14/2024] [Indexed: 04/20/2024]
Abstract
The electrokinetic process has been proposed for in-situ soil remediation to minimize excavation work and exposure to hazardous materials. The precipitation of heavy metals in alkaline pH near the cathode is still challenging. Reactive filter media and enhancement agents have been used in electrokinetics to enhance the removal of heavy metals. This study investigated coupling industrial iron slag waste and iron slag-activated carbon reactive filter media with electrokinetic for a single and mixture of heavy metals treatment. Instead of using acid enhancement agents, the anolyte solution was recycled to neutralize the alkaline front at the cathode, reducing the operation cost and chemical use. Experiments were conducted for 2 and 3 weeks at 20 mA electric current. Copper removal increased from 3.11 % to 23 % when iron slag reactive filter media was coupled with electrokinetic. Copper removal increased to 70.14 % in the electrokinetic experiment with iron slag-activated carbon reactive filter media. The copper removal increased to 89.21 % when the anolyte solution was recycled to the cathode compartment. Copper removal reached 93.45 % when the reactive filter media-electrokinetic process with anolyte recirculation was extended to 3 weeks. The reactive filter media- an electrokinetic process with anolyte recycling was evaluated for removing copper, nickel, and zinc mixture, and results revealed 81.1 % copper removal, 89.04 % nickel removal, and 92.31 % zinc removal in a 3-week experiment. The greater nickel and zinc removal is attributed to their higher solubility than copper. The results demonstrated the cost-effectiveness and efficiency of the electrokinetic with iron slag-activated carbon reactive filter media with anolyte recirculation for soil remediation from heavy metals.
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Affiliation(s)
- Faris M Hamdi
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia; Department of Civil Engineering, Jazan University, Jazan 82822, Saudi Arabia
| | - Ali Altaee
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia.
| | - Lilyan Alsaka
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia
| | - Ibrar Ibrar
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia
| | - Maryam Al-Ejji
- Center of Advanced Materials, Qatar University, PO Box 2713, Doha, Qatar
| | - John Zhou
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia
| | - Akshaya K Samal
- Centre for Nano and Material Sciences, Jain University, Ramanagara, Bangalore 562 112, Karnataka, India
| | - Alaa H Hawari
- Department of Civil and Environmental Engineering, College of Engineering, Qatar University, PO Box 2713, Doha, Qatar
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Ganbat N, Hamdi FM, Ibrar I, Altaee A, Alsaka L, Samal AK, Zhou J, Hawari AH. Iron slag permeable reactive barrier for PFOA removal by the electrokinetic process. J Hazard Mater 2023; 460:132360. [PMID: 37657326 DOI: 10.1016/j.jhazmat.2023.132360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 08/14/2023] [Accepted: 08/20/2023] [Indexed: 09/03/2023]
Abstract
The efficacy of the Standalone Electrokinetic (EK) process in soil PFAS removal is negligible, primarily due to the intersecting mechanisms of electromigration and electroosmosis transportation. Consequently, the redistribution of PFAS across the soil matrix occurs, hampering effective remediation efforts. Permeable reactive barrier (PRB) has been used to capture contaminants and extract them at the end of the EK process. This study conducted laboratory-scale tests to evaluate the feasibility of the iron slag PRB enhanced-EK process in conjunction with Sodium Cholate (NaC) biosurfactant as a cost-effective and sustainable method for removing PFOA from the soil. A 2 cm iron slag-based PRB with a pH of 9.5, obtained from the steel-making industry, was strategically embedded in the middle of the EK reactors to capture PFOA within the soil. The main component of the slag, iron oxide, exhibited significant adsorption capacity for PFOA contamination. The laboratory-scale tests were conducted over two weeks, revealing a PFOA removal rate of more than 79% in the slag/activated carbon PRB-EK test with NaC enhancement and 70% PFOA removal in the slag/activated carbon PRB-EK without NaC. By extending the duration of the slag/AC PRB-EK test with NaC enhancement to three weeks, the PFOA removal rate increased to 94.09%, with the slag/AC PRB capturing over 87% of the initial PFOA concentration of 10 mg/L. The specific energy required for soil decontamination by the EK process was determined to be 0.15 kWh/kg. The outcomes of this study confirm the feasibility of utilizing iron slag waste in the EK process to capture PFOA contaminants, offering a sustainable approach to soil decontamination. Combining iron slag PRB and NaC biosurfactant provides a cost-effective and environmentally friendly method for efficient PFOA removal from soil.
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Affiliation(s)
- Namuun Ganbat
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, Australia
| | - Faris M Hamdi
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, Australia
| | - Ibrar Ibrar
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, Australia
| | - Ali Altaee
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, Australia.
| | - Lilyan Alsaka
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, Australia
| | - Akshaya K Samal
- Centre for Nano and Material Sciences, Jain University, Ramanagara, Bangalore 562 112, Karnataka, India
| | - John Zhou
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, Australia
| | - Alaa H Hawari
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, PO Box 2713, Doha, Qatar
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