CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China , Hefei 230026, China.
Environ Sci Technol. 2017 Sep 5;51(17):10081-10089. doi: 10.1021/acs.est.7b02382. Epub 2017 Aug 14.
Lead (Pb) pollution in natural water bodies is an environmental concern due to toxic effects on aquatic ecosystems and human health, while adsorption is an effective approach to remove Pb from the water. Surface interactions between adsorbents and adsorbates play a dominant role in the adsorption process, and properly engineering a material's surface property is critical to the improvement of adsorption performance. In this study, the magnesium oxide (MgO) nanoparticles stabilized on the N-doped biochar (MgO@N-biochar) were synthesized by one-pot fast pyrolysis of an MgCl-loaded N-enriched hydrophyte biomass as a way to increase the exchangeable ions and N-containing functional groups and facilitate the adsorption of Pb. The as-synthesized MgO@N-biochar has a high performance with Pb in an aqueous solution with a large adsorption capacity (893 mg/g), a very short equilibrium time (<10 min), and a large throughput (∼4450 BV). Results show that this excellent adsorption performance can be maintained with various environmentally relevant interferences including pH, natural organic matter, and other metal ions, suggesting that the material may be suitable for the treatment of wastewater, natural bodies of water, and even drinking water. In addition, MgO@N-biochar quickly and efficiently removed Cd and tetracycline. Multiple characterizations and comparative tests have been performed to demonstrate the surface adsorption and ion exchange contributed to partial Pb adsorption, and it can be inferred from these results that the high performance of MgO@N-biochar is mainly due to the surface coordination of Pb and C═O or O═C-O, pyridinic, pyridonic, and pyrrolic N. This work suggests that engineering surface functional groups of biochar may be crucial for the development of high performance heavy metal adsorbents.
天然水体中的铅 (Pb) 污染是一个环境问题，因为它对水生态系统和人类健康具有毒性影响，而吸附是从水中去除 Pb 的有效方法。吸附剂和吸附质之间的表面相互作用在吸附过程中起主导作用，适当设计材料的表面性质对于提高吸附性能至关重要。在这项研究中，通过一锅快速热解负载 MgCl 的富氮水生植物生物质，合成了负载在 N 掺杂生物炭上的氧化镁 (MgO) 纳米粒子 (MgO@N-biochar)，以增加可交换离子和含 N 官能团的数量，并促进 Pb 的吸附。所合成的 MgO@N-biochar 在水溶液中具有很高的 Pb 性能，具有很大的吸附容量（893mg/g）、很短的平衡时间（<10min）和很大的通量大（∼4450BV）。结果表明，这种优异的吸附性能可以在各种与环境相关的干扰物存在的情况下保持，包括 pH 值、天然有机物和其他金属离子，这表明该材料可能适用于废水、天然水体甚至饮用水的处理。此外，MgO@N-biochar 还能快速有效地去除 Cd 和四环素。进行了多种表征和对比测试，以证明表面吸附和离子交换对部分 Pb 吸附的贡献，从这些结果可以推断，MgO@N-biochar 的高性能主要是由于 Pb 与 C═O 或 O═C-O、吡啶、吡啶酮和吡咯 N 的表面配位。这项工作表明，工程化生物炭的表面官能团对于开发高性能重金属吸附剂可能至关重要。
