Center of Excellence in Electrochemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
School of Chemical Engineering, College of Engineering, University of Tehran, Tehran 14176, Iran.
J Hazard Mater. 2022 Feb 15;424(Pt A):127294. doi: 10.1016/j.jhazmat.2021.127294. Epub 2021 Sep 20.
Herbal medicine wastes (HMWs) are byproducts of medicine factories, which are mainly landfilled for their environmental problems. Only bearing in mind the contamination and concerns caused by the COVID-19 pandemic and environmental emissions, the worth of herbal medicine wastes management and conversion to green products can be understood. In this work, subcritical water treatment was carried out batch-wise in a stainless tube reactor in the pressure range of 0.792-30.0 MPa, varying the temperature (127-327 °C) and time (1-60 min) of extraction. This resulted in new and green material sources, including organic acids, amino acids, and sugars. Amazingly, at very low extraction times (below 5 min) and high temperatures (above 277 °C), about 99% of HMWs were efficaciously converted to clean products by subcritical hydrothermal treatment. The results of hydrothermal extraction after 5 min indicated that at low temperatures (127-227 °C), the total organic carbon in the aqueous phase increased as the residual solid phase decreased, reaching a peak around 220 °C. Acetone soluble extracts or fat phase appeared above 227 °C and reached a maximum yield of 21% at 357 °C. Aspartic acid, threonine, and glycine were the primary amino acids; glycolic acid, formic acid, lactic acid, and acetic acid were obtained as the main organic acids, glucose, fructose, and cellobiose were substantial sugars produced from the aqueous phase after 5 min of hydrothermal subcritical hydrolysis extraction.
草药废料（HMWs）是药厂的副产品，由于其存在环境问题，主要被填埋处理。只有牢记 COVID-19 大流行和环境排放所带来的污染和关注，才能理解草药废料管理和转化为绿色产品的价值。在这项工作中，采用间歇式不锈钢管反应器在 0.792-30.0 MPa 的压力范围内进行亚临界水热处理，改变温度（127-327°C）和提取时间（1-60 min）。这产生了新的绿色材料来源，包括有机酸、氨基酸和糖。令人惊讶的是，在非常短的提取时间（低于 5 分钟）和高温（高于 277°C）下，亚临界水热处理可将约 99%的 HMWs 高效转化为清洁产品。5 分钟后水热提取的结果表明，在低温（127-227°C）下，随着残余固相的减少，水相中总有机碳增加，在 220°C 左右达到峰值。在 227°C 以上出现丙酮可溶提取物或脂肪相，在 357°C 时达到 21%的最大产率。天冬氨酸、苏氨酸和甘氨酸是主要的氨基酸；得到的主要有机酸是乙醛酸、甲酸、乳酸和乙酸；水相中在 5 分钟的亚临界水解提取后产生的大量糖是葡萄糖、果糖和纤维二糖。
