TY - JOUR
T1 - Study on the species of heavy metals in MSW incineration fly ash and their leaching behavior
AU - Jiao, Facun
AU - Zhang, Lian
AU - Dong, Zhongbing
AU - Namioka, Tomoaki
AU - Yamada, Naoomi
AU - Ninomiya, Yoshihiko
PY - 2016/11/1
Y1 - 2016/11/1
N2 - This study aims to identify the chemical species and leaching behavior of Cd, Zn, Pb, Cu and Cr in a fly ash with high content of calcium collected from the incineration of municipal solid waste (MWS), based on the sequential leaching procedure. A thermodynamic pseudo-equilibrium model was also developed to evaluate the possible chemical compounds of these heavy metals in the fly ash. The results indicate that, approximate 30% of Cu was distributed in the organic bound fraction and very likely combined with some organic ligands. Pb exhibited the highest fraction among these five metals in water soluble fraction, accounting for about 7.5%. It thus potentially causes a menace to the surroundings. In terms of model calculation, the metallic chlorides in the fly ash were responsible for the leaching of Pb, Zn, Cd and Cu even under a rigorous environmental condition (pH = 2) where the oxides and/or metallic ferrites were rarely mobile. The leaching of Cr and Cd in the fly ash was controlled by a dissolution mechanism whereas the fate of Pb, Zn and Cu was controlled by the precipitation/sorption. Cu and Zn in fly ash have been proven to associate with Ca-bearing compounds through precipitation/sorption during leaching test while Pb mainly exists as sulfate and phosphate.
AB - This study aims to identify the chemical species and leaching behavior of Cd, Zn, Pb, Cu and Cr in a fly ash with high content of calcium collected from the incineration of municipal solid waste (MWS), based on the sequential leaching procedure. A thermodynamic pseudo-equilibrium model was also developed to evaluate the possible chemical compounds of these heavy metals in the fly ash. The results indicate that, approximate 30% of Cu was distributed in the organic bound fraction and very likely combined with some organic ligands. Pb exhibited the highest fraction among these five metals in water soluble fraction, accounting for about 7.5%. It thus potentially causes a menace to the surroundings. In terms of model calculation, the metallic chlorides in the fly ash were responsible for the leaching of Pb, Zn, Cd and Cu even under a rigorous environmental condition (pH = 2) where the oxides and/or metallic ferrites were rarely mobile. The leaching of Cr and Cd in the fly ash was controlled by a dissolution mechanism whereas the fate of Pb, Zn and Cu was controlled by the precipitation/sorption. Cu and Zn in fly ash have been proven to associate with Ca-bearing compounds through precipitation/sorption during leaching test while Pb mainly exists as sulfate and phosphate.
KW - Leaching behavior
KW - MSW fly ash
KW - Sequential leaching test
KW - Thermodynamic pseudo-equilibrium model
UR - http://www.scopus.com/inward/record.url?scp=84975230175&partnerID=8YFLogxK
U2 - 10.1016/j.fuproc.2016.06.013
DO - 10.1016/j.fuproc.2016.06.013
M3 - Article
AN - SCOPUS:84975230175
VL - 152
SP - 108
EP - 115
JO - Fuel Processing Technology
JF - Fuel Processing Technology
SN - 0378-3820
ER -