Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei, 230026, Anhui, China.
Anhui Institute of Geological Experiment, Hefei, 230001, Anhui, China.
Chemosphere. 2022 Mar;290:133371. doi: 10.1016/j.chemosphere.2021.133371. Epub 2021 Dec 21.
Sewage sludge derived biochar has great potential for agricultural application, whereas the risk of heavy metals in sewage sludge is a key challenge for utilization. This study investigated the synergetic effect of co-pyrolysis and ZnCl impregnation treatment on the surface characteristics and potential ecological risk of heavy metals in sewage sludge derived biochar. It was concluded that ZnCl impregnation led to an increase in biochar yield, O and S content, but decrease the ash content and pH. Additionally, the thermal stability of ZnCl-added biochar was decreased. Semi-quantitive specific functional groups analysis suggested that ZnCl impregnation had a negative effect on the content of CO and C-O, while promoted the formation of aromatic CC. And the functional group of CO was retained in biochar by co-pyrolysis with Camellia oleifera shell due to its high content of potassium. For heavy metal passivation, ZnCl impregnation decreased total content of heavy metals by chlorination, while the oxidizable fraction (F3) of heavy metals showed an increasing tendency. Results of potential ecological risk assessment indicated that combining ZnCl impregnation and co-pyrolysis had great potential to reduce the ecological risk of heavy metals in sewage sludge derived biochar.
污水污泥衍生生物炭在农业应用方面具有巨大潜力，然而，污水污泥中的重金属风险是利用的关键挑战。本研究探讨了共热解和 ZnCl 浸渍处理对污水污泥衍生生物炭中重金属表面特性和潜在生态风险的协同作用。研究结果表明，ZnCl 浸渍导致生物炭产率增加，O 和 S 含量增加，而灰分含量和 pH 值降低。此外，添加 ZnCl 的生物炭的热稳定性降低。半定量特定官能团分析表明，ZnCl 浸渍对 CO 和 C-O 的含量有负面影响，而促进了芳族 CC 的形成。并且由于油茶壳中钾含量高，CO 官能团在共热解过程中保留在生物炭中。对于重金属钝化，ZnCl 浸渍通过氯化作用降低了重金属的总含量，而重金属的可氧化部分（F3）则呈现出增加的趋势。潜在生态风险评估结果表明，结合 ZnCl 浸渍和共热解，可极大降低污水污泥衍生生物炭中重金属的生态风险。
