title: Preferential removal and immobilization of stable and radioactive cesium in contaminated fly ash with nanometallic Ca/CaO methanol suspension.
abstract: In this work, the capability of nanometallic Ca/CaO methanol suspension in removing and/or immobilizing stable ((133)Cs) and radioactive cesium species ((134)Cs and (137)Cs) in contaminated fly ash was investigated. After a first methanol and second water washing yielded only 45% of (133)Cs removal. While, after a first methanol washing, the second solvent with nanometallic Ca/CaO methanol suspension yielded simultaneous enhanced removal and immobilization about 99% of (133)Cs. SEM-EDS analysis revealed that the mass percent of detectable (133)Cs on the fly ash surface recorded a 100% decrease. When real radioactive cesium contaminated fly ash (containing an initial 14,040Bqkg(-1)(134)Cs and (137)Cs cumulated concentration) obtained from burning wastes from Fukushima were reduced to 3583Bqkg(-1) after treatment with nanometallic Ca/CaO methanol suspension. Elution test conducted on the treated fly ash gave 100BqL(-1) total (134)Cs and (137)Cs concentrations in eluted solution. Furthermore, both ash content and eluted solution concentrations of (134)Cs and (137)Cs were much lower than the Japanese Ministry of the Environment regulatory limit of 8000Bqkg(-1) and 150BqL(-1) respectively. The results of this study suggest that the nanometallic Ca/CaO methanol suspension is a highly potential amendment for the remediation of radioactive cesium-contaminated fly ash.
authors.affiliation: Department of Civil and Environmental Engineering, University of Ulsan, Ulsan 680-749, Republic of Korea. Electronic address: srireddys@ulsan.ac.kr.
authors.forename: Srinivasa Reddy
authors.initials: SR
authors.lastname: Mallampati
authors.affiliation: 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.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Mitoma
authors.affiliation: Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Okuda
authors.affiliation: Department of Environmental Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho, Shobara City, Hiroshima 727-0023, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Sakita
authors.affiliation: Politehnica University of Bucharest, Department of Organic Chemistry, Bucharest 060042, Romania.
authors.forename: Cristian
authors.initials: C
authors.lastname: Simion
mesh_terms: D002118:Calcium / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002586:Cesium / Q000737:chemistry* / Q000302:isolation & purification; D002587:Cesium Isotopes / Q000737:chemistry / Q000302:isolation & purification; D002588:Cesium Radioisotopes / Q000737:chemistry* / Q000302:isolation & purification; D060729:Coal Ash / Q000032:analysis*; D017745:Incineration; D000432:Methanol / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry*; D012037:Refuse Disposal; D013535:Suspensions
chemical_list: D017610:Calcium Compounds; D002587:Cesium Isotopes; D002588:Cesium Radioisotopes; D060729:Coal Ash; D010087:Oxides; D013535:Suspensions; D002586:Cesium; C016538:lime; D002118:Calcium; D000432:Methanol
keywords: Contaminated fly ash; Immobilization; Methanol; Nanometallic Ca/CaO; Removal; Stable and radioactive cesium