Du Zhengliang, Hu Aibin, Wang Qiandi, Ai Jing, Zhang Weijun, Liang Yong, Cao Mengxi, Wu Hanjun, Wang Dongsheng
Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China.
Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Hazard Mater. 2022 Feb 15;424(Pt A):127346. doi: 10.1016/j.jhazmat.2021.127346. Epub 2021 Sep 26.
Sludge pyrolysis carbonization has shown potential to convert sludge biomass into multifunctional carbon materials. However, ecological risks of dissolved organic matters (DOMs) with obscure molecular characteristics retaining in sludge-based carbons (SBCs) have received little attention. This study investigated the impact of pyrolysis temperatures on the molecular conversion and biotoxicity effects of DOMs in SBCs. The results revealed that DOMs in SBCs were mainly derived from depolymerization of biopolymers and the polycondensation and cyclization of small intermediate molecules, which mainly consisted of aromatic CHON compounds with 1-3 N atoms, featuring high unsaturation and molecular weights. High-temperature pyrolysis (500-800 °C) promoted the decomposition and ring-opening of aromatic CHON compounds into saturated aliphatic CHO compounds with 2-4 O atoms in SBCs. Noteworthily, SBCs-derived DOMs showed relatively strong biotoxicity on the growth and development of wild-type zebrafish embryos, pakchoi seeds, and Vibrio qinghaiensis Q67, which was significantly related to aromatic amines, phenols, and heterocyclic-N compounds in DOMs of SBCs. SBCs-derived DOMs were mainly straight-chain fatty acids and showed no observable acute biotoxicity. This study highlights the negative impact of DOMs in SBCs on the ecological environment, and provides the theoretical basis for controlling toxic byproducts in sludge pyrolysis process.
污泥热解碳化已显示出将污泥生物质转化为多功能碳材料的潜力。然而，基于污泥的碳材料（SBCs）中保留的分子特征不明的溶解有机物（DOMs）的生态风险却很少受到关注。本研究调查了热解温度对SBCs中DOMs分子转化和生物毒性效应的影响。结果表明，SBCs中的DOMs主要来源于生物聚合物的解聚以及小分子中间体的缩聚和环化，这些小分子中间体主要由含有1-3个氮原子的芳香族CHON化合物组成，具有高度不饱和性和分子量。高温热解（500-800℃）促进了SBCs中芳香族CHON化合物分解并开环形成含有2-4个氧原子的饱和脂肪族CHO化合物。值得注意的是，SBCs衍生的DOMs对野生型斑马鱼胚胎、小白菜种子和青海弧菌Q67的生长发育表现出较强的生物毒性，这与SBCs的DOMs中的芳香胺、酚类和杂环氮化合物显著相关。SBCs衍生的DOMs主要是直链脂肪酸，未表现出明显的急性生物毒性。本研究突出了SBCs中DOMs对生态环境的负面影响，并为控制污泥热解过程中的有毒副产物提供了理论依据。
