Solvent-free synthesis and application of nano-Fe/Ca/CaO/[PO4] composite for dual separation and immobilization of stable and radioactive cesium in contaminated soils.
This study assessed the synthesis and application of nano-Fe/Ca/CaO-based composite material for use as a separation and immobilizing treatment of dry soil contaminated by stable ((133)Cs) and radioactive cesium species ((134)Cs and (137)Cs). After grinding with nano-Fe/CaO, nano-Fe/Ca/CaO, and nano-Fe/Ca/CaO/[PO4], approximately 31, 25, and 22 wt% of magnetic fraction soil was separated. Their resultant (133)Cs immobilization values were about 78, 81, and 100%, respectively. When real radioactive cesium contaminated soil obtained from Fukushima was treated with nano-Fe/Ca/CaO/[PO4], approximately 27.3 wt% of magnetic and 72.75% of non-magnetic soil fractions were separated. The highest amount of entrapped (134)Cs and (137)Cs was found in the lowest weight of the magnetically separated soil fraction (i.e., 80% in 27.3% of treated soil). Results show that (134)Cs and (137)Cs either in the magnetic or non-magnetic soil fractions was 100% immobilized. The morphology and mineral phases of the nano-Fe/Ca/CaO/[PO4] treated soil were characterized using SEM-EDS, EPMA, and XRD analysis. The EPMA and XRD patterns indicate that the main fraction of enclosed/bound materials on treated soil included Ca/PO4 associated crystalline complexes. These results suggest that simple grinding treatment with nano-Fe/Ca/CaO/[PO4] under dry conditions might be an extremely efficient separation and immobilization method for radioactive cesium contaminated soil.
Department of Civil and Environmental Engineering, University of Ulsan, Daehak-ro 93, Nam-gu, Ulsan 680-749, Republic of Korea. Electronic address: srireddys@ulsan.ac.kr.
Srinivasa Reddy
SR
Mallampati
Department of Environmental Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho Shobara City, Hiroshima 727-0023, Japan. Electronic address: mitomay@pu-hiroshima.ac.jp.
Yoshiharu
Y
Mitoma
Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513, Japan.
Tetsuji
T
Okuda
Politehnica University of Bucharest, Department of Organic Chemistry, Bucharest 060042, Romania.
Cristian
C
Simion
Department of Civil and Environmental Engineering, University of Ulsan, Daehak-ro 93, Nam-gu, Ulsan 680-749, Republic of Korea.
Byeong Kyu
BK
Lee
D000327:Adsorption; D002118:Calcium / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002586:Cesium / Q000302:isolation & purification*; D002588:Cesium Radioisotopes / Q000302:isolation & purification; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D053761:Nanocomposites / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D012990:Soil Pollutants, Radioactive / Q000302:isolation & purification*; D012995:Solubility; D013499:Surface Properties
D017610:Calcium Compounds; D002588:Cesium Radioisotopes; D010087:Oxides; D010710:Phosphates; D012990:Soil Pollutants, Radioactive; D002586:Cesium; C016538:lime; D007501:Iron; D002118:Calcium
(133)Cs; (137)Cs; Contaminated soil; Immobilization; Nano-Fe/Ca/CaO/[PO(4)]; Separation; Solvent-free synthesis