首页|Lead-chlorine synergistic immobilization mechanism in municipal solid waste incineration fly ash (MSWIFA)-based magnesium potassium phosphate cement
Lead-chlorine synergistic immobilization mechanism in municipal solid waste incineration fly ash (MSWIFA)-based magnesium potassium phosphate cement
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NETL
NSTL
Elsevier
The high chlorine (Cl) and lead (Pb) content characteristics of municipal solid waste incineration fly ash(MSWIFA) pose environmental risks and hinder resource utilization. Herein, an MSWIFA-based magnesiumpotassium phosphate cement (MKPC) preparation strategy was developed, which allowed the MSWIFA recyclingand the Pb-Cl synergistic immobilization without the washing pretreatment. The compressive strength of theresulting 10 wt% MSWIFA-based MKPC was 28.44 MPa, with over 99.2% reduction in leaching toxicity of Pb andCl. The high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) and X-rayabsorption spectroscopy (XAS) analyzes showed that Pb, phosphate and Cl- formed Pb_5(PO_4)_3Cl in MKPC. In-situX-ray diffraction (XRD) tests showed that Pb_3(PO_4)_2 was gradually transformed to Pb_5(PO_4)_3Cl through adissolution-precipitation process. The formation energy, Bader charge, charge density difference and density ofstates (DOS) of Pb_5(PO_4)_3Cl were analyzed by first-principles calculations, confirming that Pb_5(PO_4)_3Cl was morethermodynamically stable than Pb_3(PO_4)_2 and PbCl_2 and that electronic interactions between Pb-p, O-p, P-p andCl-p orbits were the origin of Pb-Cl synergistic immobilization. This work provides a new strategy for theresource utilization of MSWIFA without washing pretreatment, and provides an in-depth understanding of thePb-Cl synergistic immobilization mechanism.
NETL
NSTL
Elsevier
