Borazjani Ziba, Mastalinezhad Farzad Bayat, Osfouri Shahriar, Azin Reza
Oil and Gas Research Center, Persian Gulf University, Bushehr, Iran.
Department of Chemical Engineering, Faculty of Petroleum, Gas, and Petrochemical Engineering, Persian Gulf University, Bushehr, Iran.
Environ Sci Pollut Res Int. 2025 Apr;32(17):11179-11198. doi: 10.1007/s11356-025-36375-7. Epub 2025 Apr 8.
Hydrothermal liquefaction (HTL) offers a sustainable method for producing bio-oil from algal biomass. Evaluating the microwave- and ultrasonic-pretreatment HTL and examining the quality of bio-oil obtained from HTL of marine macroalgae, namely Sargassum and Caulerpa, are the main objectives and novelty behind this work. Algal feedstocks were pretreated by microwave (500 W and 600 W) or ultrasonic (50 W and 75 W) before heating up to 350 oC for 35 min in the HTL reactor. Results showed that Sargassum and Caulerpa displayed completely different behaviors in pretreatment. The bio-oil yield from Sargassum went up by increasing microwave and ultrasonic pretreatment power. Although the microwave-assisted HTL of Caulerpa yielded more bio-oil than ultrasonication, it did not achieve the bio-oil production levels of the conventional HTL process. The highest yield and HHV of bio-oil were obtained for 22.4 wt% and 35.56 MJ/kg for Sargassum with microwave pretreatment, while the pretreatment power had a negative effect on those from Caulerpa by decreasing quantity and quality. It was also found that 56.41% of the bio-oil components were acids for Caulerpa, and 34.6% were ketones for Sargassum under conventional HTL. Thermal weight loss analysis showed that 70.4% of the bio-oil derived from Sargassum obtained by HTL following ultrasonic pretreatment possesses a boiling point below 243 °C which suggests the higher quality of the bio-oil derived from Sargassum with a significant proportion of lighter compounds. The results indicate that the bio-oil obtained from Sargassum had a higher quantity and quality than that for Caulerpa. Besides, the carbon recovery of bio-oil indicated the highest amount of carbon (70.12 wt%) was achieved through the microwave pretreatment of Sargassum. Also, differences in the cellular structure of the raw materials resulted in different quality and quantity of bio-oil.
水热液化（HTL）为从藻类生物质中生产生物油提供了一种可持续的方法。评估微波和超声预处理的HTL以及检测从大型海藻（即马尾藻和蕨藻）的HTL中获得的生物油质量是这项工作的主要目标和创新之处。藻类原料在HTL反应器中加热至350℃并保持35分钟之前，先用微波（500W和600W）或超声（50W和75W）进行预处理。结果表明，马尾藻和蕨藻在预处理中表现出完全不同的行为。马尾藻的生物油产率随着微波和超声预处理功率的增加而提高。虽然蕨藻的微波辅助HTL产生的生物油比超声处理多，但未达到传统HTL工艺的生物油产量水平。对于经过微波预处理的马尾藻，生物油的最高产率和高热值分别为22.4 wt%和35.56 MJ/kg，而预处理功率对蕨藻的生物油产率和高热值有负面影响，使其产量和质量降低。还发现，在传统HTL条件下，蕨藻生物油成分中有56.41%是酸，马尾藻生物油成分中有34.6%是酮。热重分析表明，经超声预处理后通过HTL从马尾藻中获得生物油的70.4%沸点低于243℃，这表明来自马尾藻的生物油质量较高，含有大量较轻的化合物。结果表明，从马尾藻中获得的生物油在数量和质量上均高于蕨藻。此外，生物油的碳回收率表明，通过对马尾藻进行微波预处理可实现最高的碳含量（70.12 wt%）。而且，原材料细胞结构的差异导致生物油的质量和数量不同。
