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Marsz, Aleksandra Monika , 2014. Remediation of metal contaminated soils : evaluation of long-term effects of zero-valent iron amendments. Second cycle, A2E. Uppsala: SLU, Dept. of Soil and Environment

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Abstract

The efficiency of contaminant stabilization in soil treated with zero-valent iron (ZVI) should be evaluated in long-term experiments, as stabilization techniques do not decrease total metal concentration. With time, properties of soil can change and iron hydroxides can crystalize, what can lead to a release of contaminants. This study evaluates the influence of ZVI on arsenic, copper, cadmium and nickel solubility in contaminated soils after 16 and 6 years after applying the treatment. The soils were treated with 1% iron grit (Reppel and Louis Fargues) and 2% iron grit
(Biogeco). Louis Fargues soil was additionally treated with sewage sludge and sewage sludge with addition of 1% iron grit. Batch equilibrium experiments were performed to investigate solubility of metals in a wide pH-range (3-9). Observed solubility was evaluated using the geochemical
equilibrium program Visual MINTEQ (Cu and As). Batch experiments showed that ZVI addition did not have an influence on cadmium and nickel solubility, whereas the solubility of arsenic decreased significantly (approximately a factor of ten). Influence on copper was pH dependent – at ambient pH (ca. 6.5) the solubility was significantly reduced. In contrast, the solubility at lower pH remained the same in control and ZVI-treated soils. This behaviour could be mimicked with Visual MINTEQ,
strengthening the validity of these data. This study suggest that ZVI addition can be a suitable
remediation method for As and Cu, also in a long-term-perspective. For Cu pH needs to be kept at about 7, since binding strength of Cu by ferric (hydr)oxides decreases with decreasing pH.

Main title:Remediation of metal contaminated soils
Subtitle:evaluation of long-term effects of zero-valent iron amendments
Authors:Marsz, Aleksandra Monika
Supervisor:Berggren Kleja, Dan
Examiner:Simonsson, Magnus
Series:Examensarbeten / Institutionen för mark och miljö, SLU
Volume/Sequential designation:2014:03
Year of Publication:2014
Level and depth descriptor:Second cycle, A2E
Student's programme affiliation:NM025 EnvEuro - European Master in Environmental Science 120 HEC
Supervising department:(NL, NJ) > Dept. of Soil and Environment
Keywords:zero-valent iron, stabilization, trace elements, soil contamination, remediation
URN:NBN:urn:nbn:se:slu:epsilon-s-3116
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-s-3116
Subject. Use of subject categories until 2023-04-30.:Soil science and management
Soil chemistry and physics
Pollution
Language:English
Deposited On:18 Mar 2014 11:26
Metadata Last Modified:18 Mar 2014 11:26

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