污泥碱热处理过程中有机质转化规律与美拉德产物的生成机制

Mechanism of Organic Matter Transformation and Maillard Product Formation during Sludge Alkali-Thermal Treatment

碱热处理作为一种高效的污泥预处理技术,能够加速污泥絮体结构解体、细胞破碎和有机物的释放。而污泥碱热处理过程中会生成类黑素,但目前对于类黑素生成演变规律的研究较为有限。以市政污泥为研究对象,研究了温度和预调理方式对污泥碱热处理过程中有机物转化行为的影响,探究了污泥中有机物释放规律对美拉德反应产物——类黑素生成的影响。结果表明:温度升高会促进污泥碱热处理过程中的细胞裂解和有机物溶出,污泥中芳香蛋白类物质和溶解性微生物代谢产物会逐渐转化成腐殖酸和富里酸类物质,导致污泥腐殖化程度快速上升,并促进美拉德反应的正向进行,生成的类黑素可以使蛋白质类物质发生荧光猝灭;污泥有机物溶出量和美拉德反应产物生成量均在碱热处理温度为180℃时达到最佳;NaOH和Na_(2)SO_(3)通过加速细胞裂解和有机质溶出,从而促进美拉德反应产物的生成,且NaOH的促进作用更加显著;对于CaO预调理,由于Ca^(2+)的聚合絮凝作用会导致污泥上清液中蛋白质类物质沉降至固相中,从而抑制美拉德反应的进行。通过对比研究提出了低温(低于180℃)和CaO调理的污泥碱热处理工艺,可为污泥碱热条件控制与资源化利用提供借鉴。

As an efficient sludge pretreatment technology,alkali-thermal treatment can accelerate the disintegration of floc structure,cell fragmentation and the release of organic matter.Melanoidins are produced in the process of sludge alkali-thermal,but the research on the evolution of melanoidins is limited.Taking municipal sludge as the research object,the effects of temperature and preconditioning method on the transformation behavior of organic matter and Maillard reaction during sludge alkali-thermal were studied,and the effects of the release law of organic matter in sludge on the formation of melanoidins from Maillard reaction products were explored.The results show that the increase of temperature promotes cell lysis and organic matter dissolution during the alkali-thermal process of sludge,the aromatic proteins(APN) and soluble microbial by-products(SMPs) in sludge gradually transform into humic acid(HA) and fulvic acid(FA),resulting in a rapid increase in sludge humification degree and promoting the forward Maillard reaction,and the melanoidin produced can fluorescence quench the protein substances in sludge.Both the organic matter dissolution and the Maillard reaction of sludge are optimized when the alkali-thermal treatment temperature is 180 ℃.NaOH and Na_(2)SO_(3) promote the formation of Maillard reaction products by accelerating cell lysis and organic matter dissolution,and NaOH has a more significant promoting effect.For CaO preconditioning,the Ca^(2+) polymeric flocculation causes the protein in the sludge supernatant to settle into the solid phase,inhibiting the Maillard reaction.Through comparative study,the alkali-thermal process of sludge with low temperature(below 180 ℃) and CaO conditioning is proposed in this study,which can provide reference for the control of sludge alkali-thermal conditions and resource utilization.