Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy Evaluation
At present, contamination due to toxic metals is a global concern. The management of problems caused by heavy metals relies on stabilization/solidification, which is the most effective technique for the control of metal pollution in soil. This study examined the immobilization efficiency of various...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
|
| Series: | Toxics |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2305-6304/12/12/907 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846102610087510016 |
|---|---|
| author | Shiliang Xu Ayesha Imtiyaz Cheema Yunhui Zhang Bin Dong |
| author_facet | Shiliang Xu Ayesha Imtiyaz Cheema Yunhui Zhang Bin Dong |
| author_sort | Shiliang Xu |
| collection | DOAJ |
| description | At present, contamination due to toxic metals is a global concern. The management of problems caused by heavy metals relies on stabilization/solidification, which is the most effective technique for the control of metal pollution in soil. This study examined the immobilization efficiency of various phosphate-based binders (Na<sub>3</sub>PO<sub>4</sub>, Na<sub>2</sub>HPO<sub>4</sub>, NaH<sub>2</sub>PO<sub>4</sub>), in addition to ordinary Portland cement (OPC), MgO, and CaO, for the stabilization of multi-metal-contaminated soils. Moreover, this study focused on the leachability of copper, nickel, zinc, lead, cadmium, and manganese (Cu, Ni, Zn, Pb, Cd, Mn, respectively) over different time periods and with different concentrations. Batch leaching experiments were conducted to determine the leaching ratios and percentages of the various metal concentrations, along with measuring the pH values of the leachates. Our results indicate that the use of OPC was validated due to its superior immobilization performance across all metals present in the soil, but particularly with regard to metals in high concentrations. This was due to the formation of stable hydroxides and the high pH values, which assisted in abating the metals’ solubility. Additionally, phosphate-based binders, despite being environmentally favorable, were found to be less effective, particularly for Pb and Cu, and the leaching results exceeded non-hazardous waste limits. MgO showed reasonable immobilization results but was less effective compared to OPC; on the other hand, CaO exhibited increased leaching over time. Therefore, the present research serves primarily to highlight that OPC is more suitable for soil remediation at industrial sites and in the construction of infrastructure. Meanwhile, phosphate-based binders are shown to be more appropriate for eco-friendly, non-load-bearing applications. |
| format | Article |
| id | doaj-art-f7bb2b52e8b74bc4ba221d855c73f92d |
| institution | Kabale University |
| issn | 2305-6304 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Toxics |
| spelling | doaj-art-f7bb2b52e8b74bc4ba221d855c73f92d2024-12-27T14:56:45ZengMDPI AGToxics2305-63042024-12-01121290710.3390/toxics12120907Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy EvaluationShiliang Xu0Ayesha Imtiyaz Cheema1Yunhui Zhang2Bin Dong3College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, ChinaCollege of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, ChinaCollege of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, ChinaCollege of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, ChinaAt present, contamination due to toxic metals is a global concern. The management of problems caused by heavy metals relies on stabilization/solidification, which is the most effective technique for the control of metal pollution in soil. This study examined the immobilization efficiency of various phosphate-based binders (Na<sub>3</sub>PO<sub>4</sub>, Na<sub>2</sub>HPO<sub>4</sub>, NaH<sub>2</sub>PO<sub>4</sub>), in addition to ordinary Portland cement (OPC), MgO, and CaO, for the stabilization of multi-metal-contaminated soils. Moreover, this study focused on the leachability of copper, nickel, zinc, lead, cadmium, and manganese (Cu, Ni, Zn, Pb, Cd, Mn, respectively) over different time periods and with different concentrations. Batch leaching experiments were conducted to determine the leaching ratios and percentages of the various metal concentrations, along with measuring the pH values of the leachates. Our results indicate that the use of OPC was validated due to its superior immobilization performance across all metals present in the soil, but particularly with regard to metals in high concentrations. This was due to the formation of stable hydroxides and the high pH values, which assisted in abating the metals’ solubility. Additionally, phosphate-based binders, despite being environmentally favorable, were found to be less effective, particularly for Pb and Cu, and the leaching results exceeded non-hazardous waste limits. MgO showed reasonable immobilization results but was less effective compared to OPC; on the other hand, CaO exhibited increased leaching over time. Therefore, the present research serves primarily to highlight that OPC is more suitable for soil remediation at industrial sites and in the construction of infrastructure. Meanwhile, phosphate-based binders are shown to be more appropriate for eco-friendly, non-load-bearing applications.https://www.mdpi.com/2305-6304/12/12/907stabilization/solidificationmulti-metal contaminationphosphate bindersordinary Portland cementleachates |
| spellingShingle | Shiliang Xu Ayesha Imtiyaz Cheema Yunhui Zhang Bin Dong Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy Evaluation Toxics stabilization/solidification multi-metal contamination phosphate binders ordinary Portland cement leachates |
| title | Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy Evaluation |
| title_full | Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy Evaluation |
| title_fullStr | Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy Evaluation |
| title_full_unstemmed | Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy Evaluation |
| title_short | Application of Phosphate-Based Binders for the Stabilization and Solidification of Metal-Contaminated Soil: Mechanisms and Efficacy Evaluation |
| title_sort | application of phosphate based binders for the stabilization and solidification of metal contaminated soil mechanisms and efficacy evaluation |
| topic | stabilization/solidification multi-metal contamination phosphate binders ordinary Portland cement leachates |
| url | https://www.mdpi.com/2305-6304/12/12/907 |
| work_keys_str_mv | AT shiliangxu applicationofphosphatebasedbindersforthestabilizationandsolidificationofmetalcontaminatedsoilmechanismsandefficacyevaluation AT ayeshaimtiyazcheema applicationofphosphatebasedbindersforthestabilizationandsolidificationofmetalcontaminatedsoilmechanismsandefficacyevaluation AT yunhuizhang applicationofphosphatebasedbindersforthestabilizationandsolidificationofmetalcontaminatedsoilmechanismsandefficacyevaluation AT bindong applicationofphosphatebasedbindersforthestabilizationandsolidificationofmetalcontaminatedsoilmechanismsandefficacyevaluation |