Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China.
School of Energy Science and Engineering, University of Science and Technology of China, Guangzhou 510640, China.
Int J Mol Sci. 2023 Mar 17;24(6):5755. doi: 10.3390/ijms24065755.
The application of the adsorption method in sewage treatment has recently become a hot spot. A novel magnetic clay-biochar composite (BNT-MBC) was fabricated by co-pyrolysis of bentonite and biomass after being impregnated with Fe (NO)·9HO. Its adsorption capacity for Cd(II) and methyl orange was approximately doubled, reaching a maximum of 26.22 and 63.34 mg/g, and could be easily separated from the solution by using external magnets with its saturation magnetization of 9.71 emu/g. A series of characterizations including surface morphology and pore structure, elemental analysis, functional group analysis and graphitization were carried out, showing that the specific surface area was increased 50 times by loading 20 wt.% bentonite, while its graphitization and oxygen-containing functional groups were also enhanced. The isotherm fitting indicated that Cd(II) was adsorbed in multiple layers, while methyl orange was in both monolayer and multilayer adsorptions. The kinetic fitting indicated that chemisorption was the rate-limiting step of both, and it was also a complex process controlled by two steps with the fitting of intra-particle diffusion. In the binary system of Cd(II) and methyl orange, the co-existing pollutants facilitated the adsorption of the original one, and there was no competition between adsorption sites of Cd(II) and methyl orange. BNT-MBC also exhibited good reusability and can be magnetically recovered for recycling. Thus, the magnetic clay-biochar composite BNT-MBC is a cost-effective and promising adsorbent for simultaneous removing Cd(II) and methyl orange from wastewater.
吸附法在污水处理中的应用最近成为热点。通过将 Fe(NO3)3·9H2O 浸渍到膨润土和生物质共热解制备了一种新型磁性粘土-生物炭复合材料（BNT-MBC）。其对 Cd(II)和甲基橙的吸附容量约增加了一倍，分别达到 26.22 和 63.34mg/g，且其饱和磁化强度为 9.71emu/g，可通过外部磁铁很容易从溶液中分离出来。进行了一系列的特性分析，包括表面形貌和孔结构、元素分析、官能团分析和石墨化分析，表明负载 20wt.%膨润土可将比表面积增加 50 倍，同时也增强了其石墨化和含氧官能团。吸附等温线拟合表明 Cd(II)是多层吸附，而甲基橙则是单层和多层吸附。动力学拟合表明，化学吸附是两者的限速步骤，也是由两个步骤控制的，内扩散拟合符合该过程。在 Cd(II)和甲基橙的二元体系中，共存污染物促进了原始污染物的吸附，且 Cd(II)和甲基橙的吸附位之间没有竞争。BNT-MBC 还表现出良好的可重复使用性，可以通过磁性回收进行回收利用。因此，磁性粘土-生物炭复合材料 BNT-MBC 是一种从废水中同时去除 Cd(II)和甲基橙的具有成本效益和应用前景的吸附剂。
