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Impact of thermal soil treatment on heavy metal mobility in the context of waste management.

Authors :
Vollprecht, Daniel
Sattler, Theresa
Kern, Julia
Berrer, Iris
Pomberger, Roland
Source :
Waste Management & Research: The Journal for a Sustainable Circular Economy; Sep2024, Vol. 42 Issue 9, p832-841, 10p
Publication Year :
2024

Abstract

Thermal soil treatment is a well-established remediation method to remove organic contaminants from soils in waste management. The co-contamination with heavy metals raises the question if thermal soil treatment affects heavy metal mobility in soils. In this study, four contaminated soils and a reference sample were subjected to thermal treatment at 105°C, 300°C and 500°C for 7 day. Thermogravimetry and differential scanning calorimetry were used to understand the reactions, and resulting gases were identified by Fourier-transformed infrared spectroscopy. Treated and untreated samples were characterised by X-ray diffraction (XRD) and electron microprobe analysis and subjected to pH-dependent leaching tests, untreated samples additionally by X-ray-fluorescence (XRF) and inductively coupled plasma mass spectroscopy (ICP-MS). Leachates were analysed using ICP-MS and ion chromatography. Maximum available concentrations were used for hydrogeochemical modelling using LeachXS/Orchestra to predict leaching control mechanisms. Leaching experiments show that thermal treatment tends to decrease the mobility at alkaline pH of Pb, Zn, Cd, As and Cu, but to increase the mobility of Cr. In the acidic to neutral pH range, no clear trend is visible. Hydrogeochemical modelling suggests that adsorption processes play a key role in controlling leaching. It is suggested that the formation of minerals with a more negatively charged surface during thermal treatment are one reason why cations such as Pb<superscript>2+</superscript>, Zn<superscript>2+</superscript>, Cd<superscript>2+</superscript> and Cu<superscript>2+</superscript> are less mobile after treatment. Future research should focus on a more comprehensive mineralogical investigation of a larger number of samples, using higher resolution techniques such as nanoscale secondary ion mass spectrometry to identify surface phases formed during thermal treatment and/or leaching. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
0734242X
Volume :
42
Issue :
9
Database :
Complementary Index
Journal :
Waste Management & Research: The Journal for a Sustainable Circular Economy
Publication Type :
Academic Journal
Accession number :
179974397
Full Text :
https://doi.org/10.1177/0734242X241251398