State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
J Hazard Mater. 2024 Jan 5;461:132690. doi: 10.1016/j.jhazmat.2023.132690. Epub 2023 Oct 2.
Different pyrolysis methods, parameters and feedstocks result in biochars with different properties, structures and removal capacities for heavy metals. However, the role of each property on adsorption capacity and corresponding causal relationships remain unclear. Here, we investigated various physicochemical properties of biochar produced via three different methods and two different feedstocks to clarify influences of biomass sources and pyrolysis processes on biochar properties and its heavy metal adsorption performance. Experimental results showed biochars were more aromatic and contained more functional groups after hydrothermal carbonization, while they had developed pores and higher surface areas produced by anaerobic pyrolysis. The inclusion of oxygen resulted in more complete carbonization and higher CEC biochar. Different biochar properties resulted in different adsorption capacities. Biochar produced by aerobic calcination showed higher adsorption efficiency for Cu and Pb. Correlation analysis proved that pH, cation exchange capacity and degree of carbonization positively affected adsorption, while organic matter content and aromaticity were unfavorable for adsorption. Microstructure and components determined biochar macroscopic properties and ultimate adsorption efficiency for metal ions. This study identifies the degree of correlation and pathways of each property on adsorption, which provides guidance for targeted modification of biochar to enhance its performance in heavy metal removal.
不同的热解方法、参数和原料导致生物炭具有不同的性质、结构和重金属去除能力。然而，每种性质对吸附能力的作用及其相应的因果关系仍不清楚。在这里，我们研究了通过三种不同方法和两种不同原料制备的生物炭的各种物理化学性质，以阐明生物质来源和热解过程对生物炭性质及其重金属吸附性能的影响。实验结果表明，水热碳化后生物炭更具芳构性，含有更多的官能团，而厌氧热解则产生了发达的孔隙和更高的比表面积。氧的存在导致了更完全的碳化和更高的 CEC 生物炭。不同的生物炭性质导致了不同的吸附能力。好氧煅烧制备的生物炭对 Cu 和 Pb 的吸附效率更高。相关分析证明，pH 值、阳离子交换容量和碳化程度对吸附有积极影响，而有机质含量和芳构化程度不利于吸附。微观结构和组成决定了生物炭的宏观性质和对金属离子的最终吸附效率。本研究确定了每种性质对吸附的相关性和途径，为有针对性地改性生物炭以提高其重金属去除性能提供了指导。
