UK Biochar Research Centre, School of GeoSciences, University of Edinburgh, Crew Building, King's Building, Edinburgh, EH9 3JN, UK.
UK Biochar Research Centre, School of GeoSciences, University of Edinburgh, Crew Building, King's Building, Edinburgh, EH9 3JN, UK; Environmental Sustainability and Health Institute, Dublin Institute of Technology, Greenway Hub, Grangegorman, Dublin 7, D07 H6K8, Ireland.
Chemosphere. 2018 Sep;207:91-100. doi: 10.1016/j.chemosphere.2018.05.042. Epub 2018 May 8.
This study assessed the properties and toxicity (water cress germination trials) of 38 waste-derived, novel biochar-mineral composites (BMCs) produced via slow pyrolysis and hydrothermal carbonization (hydrochars). The biochars were produced from sewage sludge and compost-like output (CLO) by varying the type of mineral additive (zeolite, wood ash and lignite fly ash), the mineral-to-feedstock ratio and the carbonization process. While pure hydrochars completely inhibited germination of water cress, this effect was ameliorated by mineral additives. Seedlings grew best in pyrolysis chars and while wood ash addition decreased plant growth in many cases, 1:10 addition to CLO doubled germination rate. The factors responsible for the phytotoxicity can be attributed to pH, salinity and organic contaminants. Importantly, while pure minerals inhibited germination, conversion of minerals into BMCs reduced their inhibitory effects due to buffered release of minerals. Overall, mineral wastes (e.g., combustion ashes) and waste biomass can be used safely as sources of nutrients and stable organic carbon (for soil carbon sequestration) when converted into specific biochar-mineral composites, exploiting synergies between the constituents to deliver superior performance.
本研究评估了 38 种新型源自废物的生物炭-矿物复合材料（BMCs）的特性和毒性（水芹发芽试验），这些复合材料是通过慢速热解和水热碳化（水热炭）制备的。生物炭由污水污泥和类似堆肥的产物（CLO）制成，通过改变矿物添加剂的类型（沸石、木灰和褐煤灰）、矿物与原料的比例以及碳化过程来制备。虽然纯水热炭完全抑制了水芹的发芽，但矿物添加剂改善了这种抑制作用。在热解炭中，幼苗生长最好，而在许多情况下，木灰的添加会降低植物的生长，但 CLO 中添加 1:10 的木灰可使发芽率提高一倍。导致植物毒性的因素可以归因于 pH 值、盐度和有机污染物。重要的是，虽然纯矿物质抑制发芽，但由于矿物质的缓冲释放，将矿物质转化为 BMCs 降低了它们的抑制作用。总体而言，当将矿物质废物（例如燃烧灰烬）和废生物质转化为特定的生物炭-矿物复合材料时，可以安全地将其用作养分和稳定有机碳（用于土壤碳固存）的来源，利用成分之间的协同作用来提供卓越的性能。
