Effect of Accelerated Aging of MSWI Bottom Ash on the Leaching Mechanisms of Copper and Molybdenum
article
The effect of accelerated aging of Municipal Solid Waste Incinerator (MSWI) bottom ash on the leaching of Cu
and Mo was studied using a “multisurface” modeling approach, based on surface complexation to iron/aluminum
(hydr)oxides, mineral dissolution/precipitation, and metal complexation by humic substances. A novel experimental
method allowed us to identify that the solid/liquid partitioning of fulvic acids (FA) quantitatively explains the
observed beneficial effect of accelerated aging on the leaching of Cu. Our results suggest that iron/aluminum (hydr)-
oxides are the major reactive surfaces that retain fulvic acid in the bottom ash matrix, of which the aluminum (hydr)-oxides were found to increase after aging. A new modeling approach, based on the surface complexation of
FA on iron/aluminum (hydr)oxides is developed to describe the pH-dependent leaching of FA from MSWI bottom ash.
Accelerated aging results in enhanced adsorption of FA to (neoformed) iron/aluminum (hydr)oxides, leading to
a significant decrease in the leaching of FA and associated Cu. Accelerated aging was also found to reduce the
leaching of Mo, which is also attributed to enhanced adsorption to (neoformed) iron/aluminum (hydr)oxides.
These findings provide important new insights that may help to improve accelerated aging technology.
and Mo was studied using a “multisurface” modeling approach, based on surface complexation to iron/aluminum
(hydr)oxides, mineral dissolution/precipitation, and metal complexation by humic substances. A novel experimental
method allowed us to identify that the solid/liquid partitioning of fulvic acids (FA) quantitatively explains the
observed beneficial effect of accelerated aging on the leaching of Cu. Our results suggest that iron/aluminum (hydr)-
oxides are the major reactive surfaces that retain fulvic acid in the bottom ash matrix, of which the aluminum (hydr)-oxides were found to increase after aging. A new modeling approach, based on the surface complexation of
FA on iron/aluminum (hydr)oxides is developed to describe the pH-dependent leaching of FA from MSWI bottom ash.
Accelerated aging results in enhanced adsorption of FA to (neoformed) iron/aluminum (hydr)oxides, leading to
a significant decrease in the leaching of FA and associated Cu. Accelerated aging was also found to reduce the
leaching of Mo, which is also attributed to enhanced adsorption to (neoformed) iron/aluminum (hydr)oxides.
These findings provide important new insights that may help to improve accelerated aging technology.
Topics
TNO Identifier
1023548
Source
Environmental Science & Technology(40), pp. 4481-4487.
Pages
4481-4487
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