Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
Waste Manag. 2024 Dec 1;189:401-409. doi: 10.1016/j.wasman.2024.08.039. Epub 2024 Sep 5.
Stabilizing heavy metals (HMs) in sewage sludge is urgently needed to facilitate its recycling and reuse. Pyrolysis stands out as a promising method for not only stabilizing these metals but also producing biochar. Our research delves into the migration and transformation of specific HMs (Cr, Mn, Ni, Cu, Zn, As, and Pb) during co-pyrolysis under various conditions, including the presence and absence of microplastics (PVC and PET). We examined different concentrations of these plastics (1 %, 5 %, 10 %, and 15 %) and temperatures (300 °C, 500 °C, and 700 °C). Findings reveal that microplastics, particularly PVC, enhance the migration of Zn and Mn, leading to significant volatilization of Zn and Pb at higher temperatures, peaking at 700 °C. The increase in temperature also markedly influences HM migration, with As showcasing notable loss rates that climbed by 18.0 % and 16.3 % in systems with PET and PVC, respectively, as temperatures soared from 300 °C to 700 °C. Moreover, our speciation analysis indicates that microplastics aid in transforming certain HMs from unstable to more stable forms, suggesting their beneficial role in HM stabilization during pyrolysis. This study significantly enriches our understanding of microplastics' impact on HM behavior in sewage sludge pyrolysis, offering new avenues for pollution control and environmental management strategies.
稳定污水污泥中的重金属 (HM) 对于促进其回收和再利用至关重要。热解作为一种很有前途的方法，不仅可以稳定这些金属，还可以生产生物炭。我们的研究深入探讨了在不同条件下（包括存在和不存在微塑料（PVC 和 PET）的情况下），特定 HM（Cr、Mn、Ni、Cu、Zn、As 和 Pb）在共热解过程中的迁移和转化。我们研究了这些塑料的不同浓度（1%、5%、10%和 15%）和温度（300°C、500°C 和 700°C）。研究结果表明，微塑料，特别是 PVC，会促进 Zn 和 Mn 的迁移，导致 Zn 和 Pb 在较高温度下大量挥发，在 700°C 时达到峰值。温度的升高也显著影响 HM 的迁移，随着温度从 300°C 升高到 700°C，As 的损失率分别上升了 18.0%和 16.3%，在含有 PET 和 PVC 的系统中。此外，我们的形态分析表明，微塑料有助于将某些 HM 从不稳定转化为更稳定的形式，这表明它们在热解过程中对 HM 稳定化具有有益作用。这项研究极大地丰富了我们对微塑料在污水污泥热解中对 HM 行为影响的理解，为污染控制和环境管理策略提供了新的途径。
