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Heavy Metal Removal from Soils Using Magnetic Separation: 1. Laboratory Experiments
Author(s) -
Feng Nan,
Bitton Gabriel,
Yeager Philip,
Bonzongo JeanClaude,
Boularbah Ali
Publication year - 2007
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.200700087
Subject(s) - chemistry , soil water , toxicity , environmental chemistry , adsorption , metal , metal toxicity , matrix (chemical analysis) , soil test , nuclear chemistry , heavy metals , chromatography , environmental science , soil science , organic chemistry
The removal of Cu, Zn, and Cd from a sandy soil was investigated using iron filings as an adsorbent, and subsequently recovering the iron filings by magnetic separation. The best treatment was obtained by using 5% iron filings and 3 h contact time between iron filings and the soil. The metal removal efficiency from soil extracts was evaluated, using MetPLATE TM , a toxicity test that is specific for heavy metals, and the 48 h Ceriodaphnia dubia acute toxicity test. The toxicity removal was generally higher than 95% for Cu after a single treatment. With regard to Zn‐spiked soil, the toxicity removal was 96.1%, 70.0%, and 49.6% after single treatment at the input concentration of 200 mg/kg, 400 mg/kg, and 800 mg Zn 2+ /kg soil, respectively. After two or three successive treatments, more than 90% of the toxicity was removed for 400 mg/kg and 800 mg/kg Zn‐spiked soils. In the case of Cd‐spiked soil, a single treatment removed 51.1% of the toxicity from 200 mg/kg Cd‐spiked soil extracts while more than 90% of the toxicity was removed after two or three treatments. Chemical analysis and a mass balance study were also carried out to investigate the Cu distribution in the soil fractions. The results indicate that, before treatment, a large portion of Cu was immobilized in the soil matrix. Following magnetic separation, Cu was removed from both the soil matrix and extracts and was indeed adsorbed and concentrated on the iron filings. The retrieval of Cu by iron filings was further examined by energy dispersive X‐ray spectroscopy (EDS).