College of Environmental Science & Engineering, Guilin University of Technology, Guilin, 541004, People's Republic of China.
Environ Sci Pollut Res Int. 2024 Nov;31(52):61397-61425. doi: 10.1007/s11356-024-35318-y. Epub 2024 Oct 24.
Heavy metals (HMs) contamination has gained much attention due to its high degree of toxicity for living organisms. Therefore, different techniques are underway to eradicate HMs from the environment. Among the biological techniques, phytoremediation is a suitable method, but owing to the slow rate and chance of HMs penetration into the food chain, alternative techniques are needed to reduce their phytotoxicity, and biochar is one of them. Due to the diverse characteristics, biochar immobilizes HMs in the soil by improving soil pH, ion exchange, electrostatic interactions, complexation, precipitation, surface adsorption, and microbial activation. Thereby, amendment of biochar in the HMs-contaminated soils reduces HMs toxicity to plants and limits their penetration into the food chain. In contrast, some biochars have also been studied to induce metal availability in soils and subsequently its uptake by plants. This dual role of biochar depends on the feedstock of biochar, incineration temperature, and the rate of application. Moreover, biochar treatments enhance plant growth under HMs stress by improving nutrient availability, water retention capacity, scavenging of reactive oxygen species, and photosynthetic efficiency. Owing to the beneficial characteristics of biochar in HMs-contaminated sites, the number of publications has tremendously increased. Additionally, the plant species and the types of HMs that have been tested frequently under biochar treatments in these articles have been studied. Overall, the current study would help in understanding the mechanisms of how biochar influences phytoremediation of HMs and improves plant growth in HMs-polluted soils and the current scenario of the available literature.
重金属（HMs）污染因其对生物的高毒性而备受关注。因此，人们正在研究不同的技术来从环境中消除 HMs。在生物修复技术中，植物修复是一种合适的方法，但由于 HMs 进入食物链的速度缓慢且存在机会，因此需要替代技术来降低其植物毒性，生物炭就是其中之一。由于具有多种特性，生物炭通过提高土壤 pH 值、离子交换、静电相互作用、络合、沉淀、表面吸附和微生物激活等方式将 HMs 固定在土壤中。因此，在 HMs 污染土壤中添加生物炭可以降低 HMs 对植物的毒性，并限制其进入食物链。相比之下，一些生物炭也被研究用于诱导土壤中金属的有效性，随后植物吸收这些金属。生物炭的这种双重作用取决于生物炭的原料、焚烧温度和应用速率。此外，生物炭处理通过提高养分可用性、保水能力、清除活性氧和提高光合作用效率来促进 HMs 胁迫下植物的生长。由于生物炭在 HMs 污染场地中的有益特性，关于生物炭处理的出版物数量大大增加。此外，还研究了在这些文章中经常用生物炭处理测试的植物物种和 HMs 类型。总的来说，本研究将有助于了解生物炭影响 HMs 植物修复的机制以及改善 HMs 污染土壤中植物生长的机制，以及当前文献的现状。
