State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China.
College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, Guizhou, China; Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China.
Sci Total Environ. 2021 May 1;767:145305. doi: 10.1016/j.scitotenv.2021.145305. Epub 2021 Jan 22.
Biochar, a carbon-rich material, has been widely used to adsorb a range of pollutants because of its low cost, large specific surface area (SSA), and high ion exchange capacity. The adsorption capacity of biochar, however, is limited by its small porosity and low content of surface functional groups. Nano-metal oxides have a large SSA and high surface energy but tend to aggregate and passivate because of their fine-grained nature. In combining the positive qualities of both biochar and nano-metal oxides, nano-metal oxide-biochar composites (NMOBCs) have emerged as a group of effective and novel adsorbents. NMOBCs improve the dispersity and stability of nano-metal oxides, rich in adsorption sites and surface functional groups, maximize the adsorption capacity of biochar and nano-metal oxides respectively. Since the adsorption capacity and mechanisms of NMOBCs vary greatly amongst different preparations and application conditions, there is a need for a review of NMOBCs. Herein we firstly summarize the recent methods of preparing NMOBCs, the factors influencing their efficacy in the removal of several pollutants, mechanisms underlying the adsorption of different pollutants, and their potential applications for pollution control. Recommendations and suggestions for future studies on NMOBCs are also proposed.
生物炭是一种富含碳的材料，由于其成本低、比表面积大（SSA）和高离子交换容量，已被广泛用于吸附多种污染物。然而，生物炭的吸附能力受到其孔隙率小和表面官能团含量低的限制。纳米金属氧化物具有较大的 SSA 和高表面能，但由于其细粒度性质，往往容易团聚和钝化。在结合生物炭和纳米金属氧化物的优点的同时，纳米金属氧化物-生物炭复合材料（NMOBCs）作为一组有效和新颖的吸附剂出现了。NMOBCs 提高了纳米金属氧化物的分散性和稳定性，富含吸附位点和表面官能团，分别最大限度地提高了生物炭和纳米金属氧化物的吸附能力。由于 NMOBCs 在不同的制备和应用条件下的吸附容量和机制有很大的不同，因此需要对 NMOBCs 进行综述。本文首先总结了制备 NMOBCs 的最新方法，影响其去除几种污染物效果的因素，不同污染物吸附的机理，以及它们在污染控制方面的潜在应用。还对 NMOBCs 的未来研究提出了建议和展望。
