The microwave pyrolysis (MWP) of sewage sludge (SS) was conducted to investigate the impact of the organic composition of SS on the yield and composition of the derived bio-oil. The experiments were conducted in a microwave oven at 900 °C with a heating rate of 50 °C/min and achieved the product yield of 43.10 ± 2.23% bio-oil, 48.07 ± 1.26% bio-char, 8.83 ± 1.65% bio-gas. The chemical composition of bio-oil was investigated using gas chromatography–mass spectrometry and 145 species were identified. Protein and lipid contents in SS are the primary source of bio-oil yield, while bio-gas are predominantly derived from lignocellulosic materials. The unique non-thermal effects of microwaves can facilitate the ring-opening of small cycloalkanes to form straight olefins through hydrogen transfer reactions. Additionally, they can promote aldol condensation reactions, Pinacol rearrangements, and methoxy cleavage to form phenolic and aromatic structures with methyl groups. Furthermore, microwaves can aid in the dehydration, condensation, and cyclization reactions of amino acids to produce N-heterocycles while also facilitating lipid depolymerization into fragments for Diels–Alder cyclization. The results of this study will be beneficial for deeply understanding reactant characteristics and the reaction process during the MWP of SS.

中文翻译：

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微波热解污泥生产生物油：有机成分的影响和机制

对污水污泥（SS）进行微波热解（MWP），以研究SS的有机成分对衍生生物油的产量和成分的影响。实验在微波炉中进行，温度为900℃，加热速率为50℃/min，产物收率为43.10±2.23%生物油、48.07±1.26%生物炭、8.83±1.65%生物油。气体。使用气相色谱-质谱法研究了生物油的化学成分，鉴定出 145 种。 SS中的蛋白质和脂质含量是生物油产量的主要来源，而沼气主要来自木质纤维素材料。微波独特的非热效应可以促进小环烷烃通过氢转移反应开环形成直链烯烃。此外，它们还可以促进羟醛缩合反应、频哪醇重排和甲氧基裂解，形成带有甲基的酚类和芳香族结构。此外，微波可以帮助氨基酸的脱水、缩合和环化反应产生N-杂环，同时还促进脂质解聚成碎片以进行狄尔斯-阿尔德环化。本研究结果将有助于深入了解SS MWP过程中的反应物特性和反应过程。