School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China; Joint Laboratory of Northeast Agricultural University and Max Planck Institute of Colloids and Interfaces (NEAU-MPICI), Harbin 150030, China.
Joint Laboratory of Northeast Agricultural University and Max Planck Institute of Colloids and Interfaces (NEAU-MPICI), Harbin 150030, China.
J Hazard Mater. 2020 Jun 5;391:121692. doi: 10.1016/j.jhazmat.2019.121692. Epub 2019 Nov 15.
Because of its layered structure, excellent adsorption, catalytic and ion exchange properties, strong passivation, and superior adsorption capacity for heavy metals, montmorillonite as biochar modifier was introduced. Montmorillonite modified biochar composites (BC-MNT) were successfully prepared by one-step hydrothermal progress and subsequent pyrolysis for the application of Zn (II) removal from aqueous solution. Herein, our research mainly explored the effect of different hydrothermal method/pyrolysis temperatures on the adsorption properties of montmorillonite-biochar composites, since that temperature can greatly change the surface functional groups and chemical composition and structure of biochar. Primarily, adopting VK analysis method analyzed raw biochar and montmorillonite modified biochar at different temperature condition. For further research, adsorption mechanism was realized by means of SEM-EDS, XRD, FTIR, and XPS, as concluded that electrostatic interaction between the negative charge of the interlayers and Zn (II) and surface complexation took up a dominant role. The kinetic and isothermal adsorption mathematical model fitting were also performed, which was more suitable for pseudo-second order and Freundlich model, suggesting that the limited speed stage was dominated by chemical forces. The optimal preparation temperature (350 °C) and maximum adsorption amount (8.163 mg·g) were determined by the adsorption experiment model.
由于其层状结构、优异的吸附、催化和离子交换性能、强钝化性以及对重金属的优异吸附能力，蒙脱土被引入作为生物炭改性剂。通过一步水热法和随后的热解成功制备了蒙脱土改性生物炭复合材料（BC-MNT），用于从水溶液中去除 Zn（II）。在此，我们的研究主要探讨了不同水热法/热解温度对蒙脱土-生物炭复合材料吸附性能的影响，因为温度会极大地改变生物炭的表面官能团和化学成分及结构。首先，采用 VK 分析方法分析了不同温度条件下的原始生物炭和蒙脱土改性生物炭。为了进一步研究，通过 SEM-EDS、XRD、FTIR 和 XPS 等手段研究了吸附机理，得出结论，层间的负电荷与 Zn（II）之间的静电相互作用和表面络合作用占主导地位。还进行了动力学和等温吸附数学模型拟合，结果表明准二级和 Freundlich 模型更适合，表明限速阶段主要由化学力控制。通过吸附实验模型确定了最佳的制备温度（350°C）和最大吸附量（8.163mg·g）。
