Department of Environmental Science & Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, India.
Department of Environmental Science & Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, India.
J Environ Manage. 2020 Oct 15;272:111097. doi: 10.1016/j.jenvman.2020.111097. Epub 2020 Jul 23.
Surface coal mining activities completely destroy vegetation cover, soil and biodiversity. The aftermaths include huge coal mine spoil dumps, changed topography, drainage and landscape, deteriorated aesthetics and increased pollution load. These coal mine spoils are characterised by high rock fragments, extremely low water holding capacity, compacted and high bulk density, lack of organic carbon and plant nutrients, low cation exchange capacity, acidic pH and toxic metal contamination, which poses difficulties in reclamation. An array of studies has been focused on the sustainable use of biochar for restoration of degraded agricultural soil by improving the soil physicochemical, nutritional and biological properties. Although a volume of studies has been done on biochar application, its specialised application in reclamation of coal mine spoils is still atypical, also a systematic review on the mechanism by which biochar amends the mine spoil is lacking. This review focuses on i) factors affecting the biochar properties, ii) the mechanism involved in altering the physical, chemical and biological properties by biochar, (iii) remediation of potentially toxic elements in soil and restoration of degraded land using biochar, and, iv) highlighting the important aspects to be considered while using biochar for reclamation of coal mine spoil. Biochar prepared at 450 °C from a lignocellulosic rich biomass can be an alternative for reclamation for coal mine spoil. Review also suggested suitable methodologies for bulk production, application and economics of biochar in coal mine spoil reclamation.
露天采煤活动会彻底破坏植被覆盖、土壤和生物多样性。其后果包括产生大量的煤矿废石堆，地形、排水和景观发生改变，美感下降，污染负荷增加。这些煤矿废料的特点是岩石碎片含量高、持水能力极低、压实且容重大、缺乏有机碳和植物养分、阳离子交换能力低、pH 值呈酸性以及受到有毒金属污染，这些特点使得复垦变得困难。一系列研究都集中在生物炭的可持续利用上，通过改善土壤理化、营养和生物学特性来恢复退化的农业土壤。尽管已经有大量关于生物炭应用的研究，但它在煤矿废料复垦中的专门应用仍然是非典型的，也缺乏关于生物炭改良煤矿废料机制的系统综述。本综述重点关注：i）影响生物炭特性的因素，ii）生物炭改变物理、化学和生物特性的相关机制，iii）利用生物炭修复土壤中的潜在有毒元素和退化土地的恢复，以及 iv）强调在利用生物炭进行煤矿废料复垦时需要考虑的重要方面。以富含木质纤维素的生物质为原料，在 450°C 下制备的生物炭可以作为煤矿废料复垦的替代材料。综述还提出了适合大规模生产、应用和经济方面的生物炭煤矿废料复垦的方法。
