TITLE:
Feasibility of Natural Zeolite for Heavy Metal Stabilization in Municipal Solid Waste Incineration Fly Ash: A Novel Approach
AUTHORS:
Mitali Nag, Amirhomayoun Saffarzadeh, Takayuki Shimaoka
KEYWORDS:
Natural Zeolite, Mordenite, Heavy Metals, Fly ash, Adsorption
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.10 No.7,
July
13,
2022
ABSTRACT: The current study investigated the
sorption process of heavy metals, especially lead (Pb2+) and Zinc
(Zn2+), in Municipal Solid Waste Incineration (MSWI) fly ash
applying natural zeolite, namely mordenite, as an inexpensive adsorbent to
assess its feasibility for the treatment of fly ash. Batch experiments were
performed to investigate the effects of the influential parameters, such as
metals initial ion concentration, dosage of adsorbent, liquid to solid (L/S)
ratio, and equilibrium concentration of metal on the immobilization of Pb2+ and Zn2+, in a novel approach. Heavy
metals removal efficiency increased with increasing the dosage of mordenite
influenced by the media-specific surface
area. Heavy metals adsorption is ascribed to various mechanisms of ion exchange
and adsorption processes. The Langmuir and Freundlich isotherm models were
investigated using the adsorption data. The adsorption process describes better
in the Freundlich isotherm model compared to the Langmuir isotherm model with a
high determination co-efficient (R2), especially for the
adsorption of Pb2+. In addition, the affinity of mordenite to Pb2+ was shown to be higher than that of Zn2+. This allows the use of
mordenite to capture of Pb2+ in MSWI fly ash. Results raise
expectations about using mordenite as a low-cost material for treating MSWI fly
ashes. The results show that heavy metal (Pb2+ and Zn2+)
removed by mordenite adsorbent is practical and effective. In order to achieve
the higher efficiency on heavy metal stabilization in MSWI fly ash, additional
experiments are necessary.