College of Resources and Environmental Science, Northeast Agricultural University, Harbin, 150030, China; Institute of Natural Resources and Ecology Heilongjiang Academy of Sciences, National and Provincial Joint Engineering Laboratory of Wetlands and Ecological Conservation, Harbin, 150040, China.
College of Resources and Environmental Science, Northeast Agricultural University, Harbin, 150030, China.
J Environ Manage. 2020 Feb 15;256:109959. doi: 10.1016/j.jenvman.2019.109959. Epub 2019 Dec 11.
Cd pollution in aquatic environments can pose a serious threat to human health. Biochar can remove Cd from aquatic environments, but the Cdadsorption capacity of conventional biochar is low, therefore, we focused on exploring the Cd adsorption capacity of modified biochar. In this study, KMnO was used to modify vermicompost biochar (VBC), and static adsorption tests for Cd were carried out. The biochar properties and its adsorption efficiency toward Cd before and after modification were studied by kinetics and isotherm model fitting, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Additionally, an adsorption mechanism was discussed. The results showed that the KMnO-modification resulted in a successful loading of the vermicompost biochar with MnO, which greatly improved its adsorption capacity for Cd. The adsorption of Cd by VBC and MVBC was a spontaneous, endothermic, and monolayer chemical adsorption process. Mineral precipitation mechanism accounted for the largest proportion, and CdCO was the main precipitate. After modification the proportion of surface precipitation and other mechanisms (π-electron coordination and the inner/outer sphere surface coordination) increased，while adsorption via cation exchange, oxygen-containing functional groups, physical adsorption and electrostatic attraction reduced. Hence, KMnO modification has a significant effect on the Cd adsorption behavior of vermicompost biochar.
Cd 污染对水生环境构成严重威胁。生物炭可以去除水生环境中的 Cd，但常规生物炭的 Cd 吸附容量较低，因此，我们专注于探索改性生物炭的 Cd 吸附容量。本研究采用 KMnO 对蚯蚓粪生物炭（VBC）进行改性，并进行了 Cd 的静态吸附实验。通过动力学和等温线模型拟合、扫描电子显微镜（SEM）、能谱（EDS）、傅里叶变换红外光谱（FT-IR）和 X 射线光电子能谱（XPS）研究了改性前后生物炭的性质及其对 Cd 的吸附效率，并探讨了吸附机制。结果表明，KMnO 改性成功地将 MnO 负载到蚯蚓粪生物炭上，极大地提高了其对 Cd 的吸附容量。VBC 和 MVBC 对 Cd 的吸附是自发的、吸热的、单层化学吸附过程。矿物沉淀机制占比最大，主要沉淀产物为 CdCO。改性后表面沉淀和其他机制（π-电子配位和内/外球表面配位）的占比增加，而阳离子交换、含氧官能团、物理吸附和静电吸引的吸附作用减少。因此，KMnO 改性对蚯蚓粪生物炭的 Cd 吸附行为有显著影响。
