School of Ecology and Environment Studies, Nalanda University, Rajgir, Bihar 803116, India.
Department of Fisheries and Marine Science, Noakhali Science and Technology University, Noakhali, Bangladesh.
Sci Total Environ. 2023 Jan 15;856(Pt 1):159097. doi: 10.1016/j.scitotenv.2022.159097. Epub 2022 Sep 28.
The abundance of micro(nano)plastics in natural ecosystems is a crucial global challenge, as these small-sized plastic particles originate from land-based and marine-based activities and are widely present in marine, freshwater, and terrestrial ecosystems. Micro(nano)plastics can significantly be reduced through various methods, such as biological, chemical, and physical techniques. Biochar is a low-cost adsorbent and is considered an efficient material and its application is ecologically effective carbon-negative for remediation of organic and inorganic pollutants. Therefore, this review critically discusses the fate and transport of micro(nano)plastics and their interactions with different biochar in aqueous and column porous media. This review outlines the implications of biochar with the co-existence of micro(nano)plastics in efforts to understand their coupled effects on soil physicochemical properties, microbial communities, and plant growth, along with the removal of heavy metals and other toxic contaminants. In batch experiments, biochar synthesized from various biomasses such as corn straw, hardwood, pine and spruce bark, corncob, and Prosopis juliflora had shown high level of removal efficiency (>90 %) for microplastic adsorption under varying environmental conditions viz., pH, temperature, ionic strength, particle size, and dose due to chemical bonding and electrostatic attractions. Increased temperature of the aqueous solutions encouraged higher adsorption, while higher pH and dissolved organic matter and nutrients may show decreased adsorption capacities for micro(nano)plastics using biochar. Compared to other available physical, chemical, and biological methods, biochar-amended sand filters in column experiments have been very efficient in removing micro(nano)plastics. In saturated column porous media, various microplastics could be inhibited using biochar due to decreased electrostatic repulsion, steric hindrance, and competitive sorption due to humic acid, ionic strength, and cations. Finally, this review provides in-depth insights on further investigations and recommendations for overall micro(nano)plastics removal using biochar-based materials.
自然生态系统中微（纳）塑料的丰度是一个至关重要的全球性挑战，因为这些小尺寸的塑料颗粒源自陆地和海洋活动，并广泛存在于海洋、淡水和陆地生态系统中。可以通过生物、化学和物理等各种方法显著减少微（纳）塑料。生物炭是一种低成本的吸附剂，被认为是一种高效的材料，其应用对修复有机和无机污染物具有生态有效的碳负效益。因此，本综述批判性地讨论了微（纳）塑料的归宿和迁移及其与不同生物炭在水相和柱状多孔介质中的相互作用。本综述概述了生物炭与微（纳）塑料共存的意义，以了解它们对土壤物理化学性质、微生物群落和植物生长的耦合效应，以及对重金属和其他有毒污染物的去除。在批量实验中，由不同生物质（如玉米秸秆、硬木、松和云杉树皮、玉米芯和刺槐）合成的生物炭在不同环境条件下（pH 值、温度、离子强度、粒径和剂量）对微塑料的吸附表现出很高的去除效率（>90%），这是由于化学结合和静电吸引。升高水溶液的温度会促进更高的吸附，而较高的 pH 值、溶解的有机物和营养物质可能会降低生物炭对微（纳）塑料的吸附能力。与其他可用的物理、化学和生物方法相比，在柱状实验中，用生物炭改良的砂滤器在去除微（纳）塑料方面非常有效。在饱和柱状多孔介质中，由于静电斥力、空间位阻和竞争吸附的减少，生物炭可以抑制各种微塑料的迁移，这是由于腐殖酸、离子强度和阳离子的存在。最后，本综述提供了对使用基于生物炭的材料进行总体微（纳）塑料去除的进一步调查和建议的深入见解。
