Wang Xingdong, Li Chunxing, Li Zhiwei, Yu Guangwei, Wang Yin
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
Ecotoxicol Environ Saf. 2019 Jan 30;168:45-52. doi: 10.1016/j.ecoenv.2018.10.022. Epub 2018 Oct 25.
Textile dyeing sludge (TDS) was pyrolyzed at temperature ranging from 300 to 700 °C to investigate characteristics and to evaluate the risk of heavy metals (Zn, Cu, Cr, Ni, Cd, and Mn) in biochar derived from the TDS. The analyzation of characteristics and potential environmental risk evaluation of heavy metals were conducted by the BET-N, FTIR, and BCR sequential extraction procedure. The results showed that the pyrolysis treatment of the TDS contributed to the improvement of the pH value and specific surface areas with increasing pyrolysis temperature. Conversion of the TDS to biochar significantly decreased the H/C and O/C ratios, resulting in a far stronger carbonization and a higher aromatic condensation for the TDS derived biochar. The total contents of Zn, Cu, Cr, Ni and Mn in biochar increased with pyrolysis temperature owing to the thermal decomposition of organic matter in the TDS; but for Cd, the portion distributed in the biochars decreased significantly when the temperature increased up to 600 °C. However, using BCR sequential extraction procedure and analysis, it was found that pyrolysis process promoted changes in the chemical speciation and biochar matrix characteristics, leading to reduce bio-available fractions of heavy metals in the biochars. The potential environmental risk of heavy metals decreased from considerable risk in the TDS to low risk or no risk in biochar after pyrolysis above 400 °C. This work demonstrated that the pyrolysis process was a promising method for disposing of the TDS with acceptable environment risk.
对纺织印染污泥（TDS）在300至700°C的温度范围内进行热解，以研究其特性并评估热解产生的生物炭中重金属（锌、铜、铬、镍、镉和锰）的风险。通过BET-N、傅里叶变换红外光谱（FTIR）和BCR连续萃取程序对重金属的特性进行分析和潜在环境风险评估。结果表明，随着热解温度的升高，TDS的热解处理有助于pH值和比表面积的提高。TDS转化为生物炭显著降低了H/C和O/C比，导致TDS衍生生物炭的碳化程度更强，芳环缩合程度更高。由于TDS中有机物的热分解，生物炭中锌、铜、铬、镍和锰的总含量随热解温度升高而增加；但对于镉，当温度升至600°C时，其在生物炭中的分布比例显著下降。然而，通过BCR连续萃取程序和分析发现，热解过程促进了化学形态和生物炭基质特性的变化，导致生物炭中重金属的生物可利用部分减少。热解温度高于400°C后，重金属的潜在环境风险从TDS中的相当大风险降至生物炭中的低风险或无风险。这项工作表明，热解过程是一种处理TDS且环境风险可接受的有前景的方法。
