Facile preparation of rosin-based biochar coated bentonite for supporting α-Fe2O3 nanoparticles and its application for Cr(VI) adsorption
Facile preparation of rosin-based biochar coated bentonite for supporting α-Fe2O3 nanoparticles and its application for Cr(VI) adsorption
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DOI：
10.1039/c4ta06491g
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发表时间：
2015-02
影响因子：
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通讯作者：
Z. Ruan;Jinhua Wu;Jian-Fei Huang;Zuan-Tao Lin;Yanfei Li;Yonglin Liu;Piao Cao;Yueping Fang;
中科院分区：
文献类型：
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作者：
Z. Ruan;Jinhua Wu;Jian-Fei Huang;Zuan-Tao Lin;Yanfei Li;Yonglin Liu;Piao Cao;Yueping Fang;
纯纳米金属在水溶液中团聚，吸附能力较差。本研究以膨润土(BT)为载体，采用松香热解法制备生物炭(BC)来负载和分散纳米级α-Fe_2O_3(BT/BC/α-Fe_2O_3)。α-Fe_2O_3纳米粒子的生成和松香在BT表面的热解是在一步加热过程中完成的。傅立叶变换红外光谱和X射线衍射仪分析证实了松香在复合材料中裂解生成生物炭，生成了α-Fe_2O_3。此外，扫描电子显微镜图像显示，α-Fe_2O_3纳米粒子在生物炭表面分散良好。该吸附剂对六价铬具有较快的吸附性能，1min内对六价铬的去除效率可达95%，吸附容量较大，按朗缪尔模型计算，六价铬的最大脱除量可达81.7mgg−1。BT/BC/α-Fe_2O_3对Cr(VI)吸附性能的显著提高归因于α-Fe_2O_3纳米粒子在生物炭网络中的良好分散性。此外，BT/BC/α-Fe_2O_3在酸性和碱性条件下都保持了较高的铬(VI)吸附容量。结果表明，BT/BC/α-Fe_2O_3制备简单，在较宽的pH范围内具有较高的处理效率，可用于废水中铬(VI)的快速去除或铬(VI)的紧急渗漏。
Pure nanometals have poor adsorption capacity due to their agglomeration in aqueous solution. In this study, biochar (Bc) prepared by the pyrolysis of rosin and coated on bentonite (Bt) was designed to support and disperse nanoscale α-Fe2O3 (Bt/Bc/α-Fe2O3). The generation of α-Fe2O3 nanoparticles and the pyrolysis of rosin on the surface of Bt were accomplished in a one-step heating route. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the pyrolysis of rosin into biochar and the production of α-Fe2O3 in the composite. Besides, scanning electron microscopy (SEM) images showed good dispersion of α-Fe2O3 nanoparticles on the biochar surface. This adsorbent demonstrated fast Cr(VI) adsorption property with a Cr(VI) removal efficiency of 95% within one minute and high Cr(VI) adsorption capacity with a maximum Cr(VI) removal up to 81.7 mg g−1 based on the Langmuir model. The remarkable improvement of Cr(VI) adsorption on Bt/Bc/α-Fe2O3 was attributed to the good dispersion of α-Fe2O3 nanoparticles by the biochar network in comparison with other similar adsorbents. In addition, Bt/Bc/α-Fe2O3 maintained high Cr(VI) adsorption capacity under both acidic and basic conditions. This indicated that Bt/Bc/α-Fe2O3 can be used for fast Cr(VI) removal from wastewater or emergent Cr(VI) leakage due to its facile preparation and high efficiency in a wide range of pH.