Jiangdong Dai,Sujun Tian,Yinhua Jiang,Zhongshuai Chang,Atian Xie,Ruilong Zhang,Chunxiang Li,Yongsheng Yan
Here, the magnetic hierarchical porous carbon (MHPC) with micromesopores was first prepared using ethylenediaminetetraacetic acid tripotassium (EDTA-3K) and iron nitrate by simultaneous magnetization/activation method. The optimal product was MHPC-20 with a high graphitization, which possessed a large SBET (1688 m2 g–1) and saturation magnetization (3.679 emu g–1). As expected, MHPC-20 had a very high maximum adsorption capacity (534.2 mg g–1) toward chloramphenicol (CAP) from water solution at 298 K with a positive correlation between SBET and adsorption amount. Additionally, MHPC-20 had a fast adsorption kinetic, only 250 min, and isothermal and kinetics data were well fitted by Langmuir and pseudo-second-order kinetic models, respectively. Moreover, the effect of ion strength, solution pH, and humic acid on CAP adsorption onto MHPC-20 were investigated, indicating a better stability. Besides, MHPC-20 showed good reusability and excellent magnetic separation performance, which implied MHPC-20 as a candidate could be applied in various complex wastewater environments.
Previous research has fully demonstrated that the core–shell spherical structure can facilitate multiple reflection within the cavity and provide polarization relaxation at the heterogeneous interfaces. In this study, double-shell nitrogen-doped carbon-Fe 3 C-Fe (NC-Fe 3 C-Fe, referred to as CFF) nanospheres composed of hollow NC-Fe 3 C and solid NC-Fe 3 C/Fe nanospheres are synthesized in an interconnected three-dimensional structure. The double-shell is composed of nitrogen-doped carbon outer shells and Fe 3 C inner shells, derived from the carbonization of polydopamine (PDA) and controllable etching of the Fe nanotemplates in the PDA@Fe. In this strategy, the carbon shells provide dielectric loss, and the Fe 3 C and Fe contribute to magnetic loss, bringing about a magnetic-electric synergistic effect on effective electromagnetic wave absorption (EMA). By adjusting the thickness of the carbon shells and the etching time of the Fe, the CFF achieves a minimum reflection loss of −74.00 dB at a thickness of 1.91 mm, with an effective absorption bandwidth of 5.04 GHz. In addition, by the radar cross-section (RCS) scattering simulation, the RCS value at a scattering angle of 0° decreased by 32.06 dBm 2 , confirming an excellent EMA capability in practical far-field applications. This study provides an effective strategy for the application of core–shell and double-shell structures in the EMA materials.
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