Heavy metals leachability in fly ash remediated soil

Devagi Kanakaraju, . and Dayang Norfadzila, . and Hollena Nori, . and Rafeah Wahi, . Heavy metals leachability in fly ash remediated soil. pp. 37-49. ISSN 1823-8556

This study focused on recycling fly ash a by-product of power plants to stabilize heavy metals in contaminated soil. Fly ash collected from the Sejingkat power plant in Kuching Sarawak was applied to soil from the roadside. The potential risk associated with the application of fly ash on the soil was assessed in terms of heavy metal concentration in leaching experiments. Deionized water and acidified water (deionized water acidified to pH 4.0 with nitric acid) were used as leaching agents and passed through columns filled with untreated soil and soil-fly ash mixture (9:1). The Cd Zn Ni Mn Cu and Fe content in leachates were assessed at Day 0 5 10 and 15 after stabilization. Leachate from the soil-fly ash mixture with acidified water had low pH range (4.5-6.2) compared to soil-fly ash mixture with deionized water (5.8-6.2) and this affected the solubility of heavy metals. The concentration of the metals in soil-fly ash mixture with acidified water leachate was higher than soil-fly ash mixture with deionized water. In contrast untreated soil did not show any clear pattern of heavy metal reduction except for Ni. Except for Cr the concentrations of all the tested heavy metals in treated soil decreased with increasing pH as well as electrical conductivity from Day 0 to 15 of contact time. The results suggested that the solubility of heavy metals in soil leachate was influenced by pH and the type of leaching agent. Therefore the application of fly ash as a soil remediation agent may be a sustainable option to manage this by-product.

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Abstract

This study focused on recycling fly ash a by-product of power plants to stabilize heavy metals in contaminated soil. Fly ash collected from the Sejingkat power plant in Kuching Sarawak was applied to soil from the roadside. The potential risk associated with the application of fly ash on the soil was assessed in terms of heavy metal concentration in leaching experiments. Deionized water and acidified water (deionized water acidified to pH 4.0 with nitric acid) were used as leaching agents and passed through columns filled with untreated soil and soil-fly ash mixture (9:1). The Cd Zn Ni Mn Cu and Fe content in leachates were assessed at Day 0 5 10 and 15 after stabilization. Leachate from the soil-fly ash mixture with acidified water had low pH range (4.5-6.2) compared to soil-fly ash mixture with deionized water (5.8-6.2) and this affected the solubility of heavy metals. The concentration of the metals in soil-fly ash mixture with acidified water leachate was higher than soil-fly ash mixture with deionized water. In contrast untreated soil did not show any clear pattern of heavy metal reduction except for Ni. Except for Cr the concentrations of all the tested heavy metals in treated soil decreased with increasing pH as well as electrical conductivity from Day 0 to 15 of contact time. The results suggested that the solubility of heavy metals in soil leachate was influenced by pH and the type of leaching agent. Therefore the application of fly ash as a soil remediation agent may be a sustainable option to manage this by-product.

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Item Type:	Article
AGROVOC Term:	Contaminated soils
AGROVOC Term:	Heavy metals
AGROVOC Term:	Leaching
AGROVOC Term:	Ashes
AGROVOC Term:	Byproducts
AGROVOC Term:	Coal byproducts
AGROVOC Term:	Leachates
AGROVOC Term:	Soil improvement
AGROVOC Term:	Physicochemical properties
AGROVOC Term:	Solubility
Depositing User:	Mr. AFANDI ABDUL MALEK
Last Modified:	24 Apr 2025 00:54
URI:	http://webagris.upm.edu.my/id/eprint/8108

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