Xiao Siwei, Wang Leshi, Bian Jing, Wang Nan, Zhang Qian, Li Yuanbo, Hao Jiuxiao
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, School of Environmental Science and Engineering, Beijing University of Technology, Beijing 100124, PR China.
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, School of Environmental Science and Engineering, Beijing University of Technology, Beijing 100124, PR China.
J Hazard Mater. 2025 Mar 5;485:136908. doi: 10.1016/j.jhazmat.2024.136908. Epub 2024 Dec 17.
The melanoidins formed through the Maillard reaction during thermal hydrolysis pretreatment (THP) of sludge contribute to darkening, refractoriness, and inhibition of effective wastewater and sludge treatment. However, the dynamic production and structural evolution of THP-derived melanoidins are not fully understood. This study aimed to investigate the factors influencing melanoidins production and the associated mechanisms during THP. Response surface methodology analysis revealed that temperature had the greatest impact on melanoidins production compared to heating time and initial pH. Comparing treatments at 135 °C, 165 °C, and 195 °C, melanoidins production initially increased with rising temperature and then declined. Structural changes and substance transformations during melanoidins production at different temperatures were elucidated via two-dimensional correlation Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry, respectively. Few competitive reactions occurred at 135 °C; however, carbonization competed with the Maillard reaction for substrates at 165 °C, while carbonization and caramelization led to substrate competition and degradation of the already formed melanoidins at 195 °C. These findings shed light on the dynamic process and mechanisms underlying melanoidins production during THP, and provide fundamental insight into melanoidins regulation for future research.
在污泥的热水解预处理（THP）过程中，通过美拉德反应形成的类黑素会导致颜色加深、难降解性增加，并抑制有效的废水和污泥处理。然而，THP衍生类黑素的动态生成和结构演变尚未完全明晰。本研究旨在探究THP过程中影响类黑素生成的因素及相关机制。响应面法分析表明，与加热时间和初始pH相比，温度对类黑素生成的影响最大。比较135℃、165℃和195℃下的处理，类黑素生成量最初随温度升高而增加，随后下降。分别通过二维相关傅里叶变换红外光谱和气相色谱-质谱联用技术阐明了不同温度下类黑素生成过程中的结构变化和物质转化。在135℃时几乎没有竞争性反应发生；然而，在165℃时碳化与美拉德反应竞争底物，而在195℃时碳化和焦糖化导致底物竞争并使已形成的类黑素降解。这些发现揭示了THP过程中类黑素生成的动态过程和机制，并为未来研究中类黑素的调控提供了基本见解。
