Department of the Environmental Chemistry & Technology, Faculty of the Environment, Jan Evangelista Purkyně University, Pasteurova 15, Ústí nad Labem, 400 96, Czech Republic.
Department of the Environmental Chemistry & Technology, Faculty of the Environment, Jan Evangelista Purkyně University, Pasteurova 15, Ústí nad Labem, 400 96, Czech Republic; Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Al-Farabi 71, Almaty, 05 00 40, Kazakhstan.
J Environ Manage. 2021 Jul 15;290:112611. doi: 10.1016/j.jenvman.2021.112611. Epub 2021 Apr 20.
To complete a loop of the Miscanthus value chain including production, phytomanagement, conversion to energy, and bioproducts, the wastes accumulated from these processes have to be returned to the production cycle to provide sustainable use of the feedstock, to reduce costs, and to ensure a zero-waste approach. This can be achieved by converting Miscanthus feedstock into biogas and biochar using pyrolysis and then returning biochar to the production cycle of Miscanthus crop applications in the phytotechnology of trace elements (TEs)-contaminated/marginal lands. These processes are subjects of the current review, which focused on the peculiarities of biochar received from Miscanthus by pyrolysis, its properties, the impact on soil characteristics, the phytoremediation process, biomass yield, and the abundance of soil biodiversity. Results from the literature indicated that the pH, surface area, and porosity of Miscanthus biochar are important in determining its impact on soil characteristics. It was inferred that the most effective Miscanthus biochar was produced with a pyrolysis temperature of about 600 °C with a residence time from about 30 min to an hour. Another important factor that determined the impact of Miscanthus biochar on soil health is the application rate: with its increase, the effect became more essential, and the recommended rate is between 5% and 10%. The influence of Miscanthus biochar on the TEs phytoremediation parameters is less studied, generally Miscanthus biochar produced at higher temperatures and added with higher application rates is more likely to restrict the mobility and availability of TEs by different plants. However, some published results are contradictory to these conclusions and showed absence of significant difference in TEs reduction during application of different Miscanthus biochar doses. The future experimental studies have to focus on determining the impact of a technological pyrolysis regime on Miscanthus biochar properties on TEs-contaminated or marginal land when biochar will be obtained from contaminated rhizomes and waste after the application of phytotechnology. In addition, studies must explore the influence of this biochar on TEs phytoparameters, enhancements in biomass yield, improvements in soil parameters, and the abundance of soil diversity.
要完成芒草价值链的循环，包括生产、植物管理、转化为能源和生物制品，必须将这些过程中积累的废物返回生产循环，以实现原料的可持续利用、降低成本，并确保采用零废物方法。这可以通过利用热解将芒草原料转化为沼气和生物炭来实现，然后将生物炭返回受痕量元素（TEs）污染/边缘土地的植物技术中芒草作物应用的生产循环。这些过程是当前综述的主题，重点关注热解从芒草中获得的生物炭的特性、性质、对土壤特性的影响、植物修复过程、生物量产量和土壤生物多样性的丰富度。文献结果表明，芒草生物炭的 pH 值、表面积和孔隙率是决定其对土壤特性影响的重要因素。据推断，在 600°C 左右的热解温度下，用大约 30 分钟至 1 小时的停留时间生产的芒草生物炭最为有效。另一个决定芒草生物炭对土壤健康影响的重要因素是施用量：随着施用量的增加，效果变得更加重要，推荐的用量在 5%到 10%之间。芒草生物炭对 TEs 植物修复参数的影响研究较少，一般来说，在较高温度下生产并添加较高用量的芒草生物炭更有可能通过不同的植物限制 TEs 的迁移性和可用性。然而，一些已发表的结果与这些结论相矛盾，表明在应用不同剂量的芒草生物炭时，TEs 的减少没有显著差异。未来的实验研究必须侧重于确定在获得来自污染根茎和植物技术应用后的废物的生物炭时，技术热解制度对芒草生物炭特性的影响对受 TEs 污染或边缘土地的影响。此外，研究必须探索这种生物炭对 TEs 植物参数、生物量产量提高、土壤参数改善和土壤多样性丰富度的影响。
