| 文旦皮-污泥共热解对市政污泥中重金属的稳定化 |
| 摘要点击 974 全文点击 155 投稿时间：2023-12-04 修订日期：2024-04-20 |
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| 中文关键词 共热解 污泥 文旦皮 重金属 风险 |
| 英文关键词 co-pyrolysis sludge shaddock peel heavy metals risk |
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| 中文摘要 |
| 通过热解和共热解制备了市政污泥生物炭,并研究了热解温度（400~800 ℃）和文旦皮的添加对生物炭性质、重金属（Cu、Zn、Pb、Cd、Ni和Cr）含量及其环境风险的影响．结合生物炭表征结果及重金属含量分析发现,共热解作用促进了稳定晶体矿物[如CdPbO3、Pb5（PO4）3OH、CuCl和ZnS]的形成,同时重金属与—OH和—CO—NH—等官能团的络合作用或与芳香基团提供的π电子结合也进一步提高了其稳定化效果,而比表面积和孔隙度的增加导致的表面吸附和孔隙填充作用在重金属（Cd、Cr、Pb和Zn）稳定化作用中占主导地位,但官能团的络合作用是低温热解下Cu和Ni稳定化的主要作用．共热解生物炭的重金属的浸出浓度远低于《危险废物鉴别标准浸出毒性鉴别》（GB 5085.3-2007）限值,潜在生态风险指数（RI值）显著降低．研究结果为市政污泥和生物质废弃物的安全处置提供了理论基础和技术支持． |
| 英文摘要 |
| Co-pyrolysis with other biomass is a promising method for municipal sludge treatment and has attracted great attention. However, the dominant mechanism by which the heavy metals in municipal sludge are immobilized during the co-pyrolysis remains unknown. In this study, municipal-sludge biochar was prepared by pyrolysis and co-pyrolysis, and the effects of pyrolysis temperature （400-800 ℃） and the addition of shaddock peel on the properties of biochar, the contents of heavy metals （Cu, Zn, Pb, Cd, Ni, and Cr）, and their environmental risks were investigated. Based on the analysis of characterization results and heavy metal contents in the biochar, it was observed that co-pyrolysis promoted the formation of stabilized crystalline minerals （e.g., CdPbO3, Pb5（PO4）3OH, CuCl, and ZnS）, which reduced the potential risk of heavy metals in biochar. Furthermore, aromatic groups were detected and could interact with heavy metals through cation-π interaction. Further analysis revealed that the immobilization was enhanced by the complexation between heavy metals and the functional groups in biochar, such as —OH and —CO—NH—, which played the main role in the stabilization of Cu and Ni at low pyrolysis temperatures. However, surface sorption and pore filling, due to the increase in specific surface area and porosity, dominated the immobilization of Cd, Cr, Pb, and Zn. The leaching concentrations of heavy metals in co-pyrolysis biochar were much lower than the limit values of "Identification Standards for Hazardous Wastes-Identification for Extraction Toxicity" （GB 5085.2-2007） and those by US EPA 1311, 1990. Additionally, the potential ecological risk index （RI value） of heavy metals in biochar was significantly reduced by co-pyrolysis compared to that of sludge or biochar without the co-pyrolysis. This study reveals the dominant immobilization mechanism for specific heavy metals during co-pyrolysis of municipal sludge with shaddock peel and provides an alternative practical strategy for the safe disposal of municipal sludge and biomass wastes. |
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