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<p>Municipal solid waste incineration fly ash (MSWI FA), classified as hazardous waste in China, contains considerable amounts of toxic heavy metals that can pose significant environmental and public health risks, yet the influence of particle size on its physicochemical properties, heavy metal speciation, leaching behavior and integrated ecological risk remains insufficiently understood. In this study, MSWI FA from a grate furnace in Eastern China was sieved into five particle-size fractions (≤ 38&#xa0;μm to 200–450&#xa0;μm) and analyzed using morphological, mineralogical, thermal, and surface characterization techniques. Heavy metal speciation was determined via the European Community Bureau of Reference (BCR) sequential extraction method, and leaching behavior was assessed using three Chinese standard protocols (HJ 557-2010, HJ/T 299-2007, HJ/T 300-2007). Ecological risk was evaluated with an overall pollution toxicity index (OPTI). All fractions were dominated by Ca- and Cl-rich minerals, mainly Ca(OH)Cl, CaSO<sub>4</sub>, KCl, and NaCl. Semi‑volatile metals (Zn, Pb, Cd) showed bimodal enrichment in the finest (≤ 38&#xa0;μm) and coarsest (200–450&#xa0;μm) fractions. Sequential extraction revealed Cr predominantly in residual form, Zn, Cd and Cu mainly in reducible form. Leaching behavior varied with particle size and pH: HJ/T 300‑2007 promoted Zn release from the ≤ 38&#xa0;μm fraction due to lower leachate pH, while Pb dissolution was enhanced in alkaline leachates from HJ 557‑2010 and HJ/T 299‑2007. The OPTI identified ≤ 38&#xa0;μm particles as posing the highest ecological risk, with Zn dominating risk under weak‑acid conditions and Pb under neutral and strong‑acid protocols. These findings highlight the importance of particle-size‑specific control strategies for reducing environmental risks associated with MSWI FA and enhancing safe disposal or resource utilization.</p>

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Physicochemical properties, heavy metal speciation and environmental risk assessment of municipal solid waste incineration fly ash from Eastern China: a particle size-dependent investigation

  • 期刊论文

  • 发表日期：

    2025年11月6日

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  • Chunxi Kang,
  • Yunhui Lan,
  • Xinxing Xu,
  • Yanran Zhong,
  • Jun Xiong

摘要

Municipal solid waste incineration fly ash (MSWI FA), classified as hazardous waste in China, contains considerable amounts of toxic heavy metals that can pose significant environmental and public health risks, yet the influence of particle size on its physicochemical properties, heavy metal speciation, leaching behavior and integrated ecological risk remains insufficiently understood. In this study, MSWI FA from a grate furnace in Eastern China was sieved into five particle-size fractions (≤ 38 μm to 200–450 μm) and analyzed using morphological, mineralogical, thermal, and surface characterization techniques. Heavy metal speciation was determined via the European Community Bureau of Reference (BCR) sequential extraction method, and leaching behavior was assessed using three Chinese standard protocols (HJ 557-2010, HJ/T 299-2007, HJ/T 300-2007). Ecological risk was evaluated with an overall pollution toxicity index (OPTI). All fractions were dominated by Ca- and Cl-rich minerals, mainly Ca(OH)Cl, CaSO4, KCl, and NaCl. Semi‑volatile metals (Zn, Pb, Cd) showed bimodal enrichment in the finest (≤ 38 μm) and coarsest (200–450 μm) fractions. Sequential extraction revealed Cr predominantly in residual form, Zn, Cd and Cu mainly in reducible form. Leaching behavior varied with particle size and pH: HJ/T 300‑2007 promoted Zn release from the ≤ 38 μm fraction due to lower leachate pH, while Pb dissolution was enhanced in alkaline leachates from HJ 557‑2010 and HJ/T 299‑2007. The OPTI identified ≤ 38 μm particles as posing the highest ecological risk, with Zn dominating risk under weak‑acid conditions and Pb under neutral and strong‑acid protocols. These findings highlight the importance of particle-size‑specific control strategies for reducing environmental risks associated with MSWI FA and enhancing safe disposal or resource utilization.