School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou 510006, China.
Chemosphere. 2023 Jan;311(Pt 1):136976. doi: 10.1016/j.chemosphere.2022.136976. Epub 2022 Oct 23.
α-FeO modified biochar (FeO/BC) was prepared to remove Cu(II), Pb(II) and As(V). By adjusting the calcination temperature, the morphology and exposed crystal facets of α-FeO on the biochar were changed which further affected the adsorption performance. The kinetics and isotherms were investigated systematically to reveal adsorption effect of the adsorbent on Cu(II), Pb(II) and As(V). The results indicated that chemisorption process was the dominant adsorption mechanism. FeO/BC-350 exhibited superior adsorption capacity for Cu(II) (258.22 mg/g) and Pb(II) (390.60 mg/g), and FeO/BC-250 showed relatively good adsorption capacity for As(V) (5.78 mg/g). By adsorption mechanism analysis, electrostatic adsorption, ion exchange, precipitation and complexation were coexisted in the process of removing metal ions by FeO/BC. The repeatability test and the effect of ion strength exhibited the strong stability of FeO/BC. Meanwhile, density functional theory (DFT) calculations manifested that the (202) facet of α-FeO on FeO/BC-350 possessed the lowest adsorption energies of Cu(II) and Pb(II). While for As(V), it was the (104) facet of α-FeO on FeO/BC-250 that exhibited the lowest adsorption energy. DFT results revealed that different FeO/BC had different adsorption affinities to various heavy metals. In general, this work not only prepared a promising adsorbent via a simple procedure, but also served as a reference for researchers in designing absorbents with specific active facet for efficient heavy metals remediation.
α-FeO 修饰生物炭（FeO/BC）被制备用于去除 Cu(II)、Pb(II) 和 As(V)。通过调整煅烧温度，改变了生物炭上α-FeO 的形态和暴露的晶面，从而进一步影响了吸附性能。系统研究了动力学和等温线，以揭示吸附剂对 Cu(II)、Pb(II) 和 As(V)的吸附效果。结果表明，化学吸附过程是主要的吸附机制。FeO/BC-350 对 Cu(II)（258.22mg/g）和 Pb(II)（390.60mg/g）具有优异的吸附容量，而 FeO/BC-250 对 As(V)（5.78mg/g）具有相对较好的吸附容量。通过吸附机制分析，在 FeO/BC 去除金属离子的过程中，静电吸附、离子交换、沉淀和络合同时存在。重复性试验和离子强度的影响表明 FeO/BC 具有很强的稳定性。同时，密度泛函理论（DFT）计算表明，FeO/BC-350 上α-FeO 的（202）晶面具有最低的 Cu(II) 和 Pb(II) 吸附能。而对于 As(V)，则是 FeO/BC-250 上的α-FeO 的（104）晶面具有最低的吸附能。DFT 结果表明，不同的 FeO/BC 对各种重金属具有不同的吸附亲和力。总的来说，这项工作不仅通过简单的方法制备了一种有前途的吸附剂，而且为研究人员设计具有特定活性面的吸附剂以有效去除重金属提供了参考。
