磁性壳聚糖/Fe_(3)O_(4)/氧化石墨烯吸附剂的制备及其多染料吸附性能

Preparition and multiple-dye-adsorption of magnetic chitosan/Fe_(3)O_(4)/graphene oxide adsorbent

为了提高壳聚糖的多染料吸附性能并使其便于固液分离,采用共沉淀法制备了壳聚糖、磁铁矿纳米颗粒、氧化石墨烯复合磁性吸附剂(CS/Fe_(3)O_(4)/GO)。系统的结构表征显示,CS包覆的Fe_(3)O_(4)磁性纳米颗粒均匀地分布在GO的表面。CS/Fe_(3)O_(4)/GO具有高达42.5 emu·g^(-1)的室温铁磁性,因此可在外加磁场中实现高效固液分离。研究表明,CS/Fe_(3)O_(4)/GO对亚甲基蓝(MB)、甲基橙(MO)和刚果红(CR)等多种染料具有良好的吸附性能,溶液的pH、初始浓度和吸附时间对其多染料吸附性能具有显著影响。在最佳条件下,CS/Fe_(3)O_(4)/GO对MB、MO和CR的吸附量分别达到210.6、258.6和308.9 mg·g^(-1)。CS/Fe_(3)O_(4)/GO具有优异的循环利用性能,经5次循环后仍能保留90%以上的原始吸附量。采用吸附等温线和吸附动力学对CS/Fe_(3)O_(4)/GO的多染料吸附性能进行了拟合分析,并详细讨论了其吸附机理。

To improve the multiple‑dye adsorption performance of the adsorbent and endow it with magnetism,a magnetic composite adsorbent composed of chitosan,magnetite nanoparticles,and graphene oxide(CS/Fe_(3)O_(4)/GO)was prepared by a simple co‑precipitation method.Careful structural investigations indicated that magnetite nanoparticles covered by CS were evenly distributed on the surface of graphene oxide.CS,Fe_(3)O_(4),and GO were chemically bonded together to form a stable composite material.The magnetism of CS/Fe_(3)O_(4)/GO was tested as 42.5 emu·g^(-1),which is strong enough for efficient solid‑liquid separation under an applied magnetic field.CS/Fe_(3)O_(4)/GO was used to adsorb multiple synthetic dyes,including methylene blue(MB),Congo red(CR),and methyl orange(MO),and showed high multi‑dye adsorption performance.It is found that the adsorption of MB,MO,and CR under optimal conditions reached 210.6,258.6,and 308.9 mg·g^(-1),respectively.The effect of pH,initial concentration,and contact time on the adsorption was investigated.Recycling experiments showed that CS/Fe_(3)O_(4)/GO had excellent reusability more than 90%of the original adsorption capacity remained after five cycles.Adsorption isotherm and adsorption kinetics were employed to fit the multi‑dye adsorption performance of CS/Fe_(3)O_(4)/GO,and the adsorption mechanism was discussed in detail.