UK Biochar Research Centre, School of Geosciences, University of Edinburgh, Crew Building, Alexander Crum Brown Road, Edinburgh EH9 3FF, UK.
Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden; RISE Processum AB, SE-89122 Örnsköldsvik, Sweden.
Bioresour Technol. 2023 Oct;386:129567. doi: 10.1016/j.biortech.2023.129567. Epub 2023 Jul 26.
Microalgae, originating from a tertiary treatment of municipal wastewater, is considered a sustainable feedstock for producing biochar and hydrochar, offering great potential for agricultural use due to nutrient content and carbon storage ability. However, there are risks related to contamination and these need to be carefully assessed to ensure safe use of material from wastewater microalgae. Therefore, this study compared the properties and phototoxicity of biochar and hydrochar produced via pyrolysis and hydrothermal carbonisation (HTC) of microalgae under different temperatures and residence times. While biochar promoted germination and seedling growth by up to 11.0% and 70.0%, respectively, raw hydrochar showed strong phytotoxicity, due to the high content of volatile matter. Two post-treatments, dichloromethane (DCM) washing and further pyrolysis, proved to be effective methods for mitigating phytotoxicity of hydrochar. Additionally, biochar had 35.8-38.6% fixed carbon, resulting in higher carbon sequestration potential compared to hydrochar.
微藻源自城市污水的三级处理，被认为是生产生物炭和水热炭的可持续原料，由于其营养成分和碳储存能力，在农业中具有很大的应用潜力。然而，与污染相关的风险需要仔细评估，以确保安全使用来自废水微藻的材料。因此，本研究比较了在不同温度和停留时间下通过热解和水热碳化（HTC）制备的微藻生物炭和水热炭的特性和光毒性。生物炭通过提高发芽率和幼苗生长率分别高达 11.0%和 70.0%，而原始水热炭由于挥发物含量高，表现出很强的植物毒性。两种后处理方法，二氯甲烷（DCM）洗涤和进一步热解，被证明是减轻水热炭植物毒性的有效方法。此外，生物炭的固定碳含量为 35.8-38.6%，与水热炭相比，具有更高的碳封存潜力。
