氨基功能化磁性CoFe_2O_4/氧化石墨烯去除电镀废水中Cr(Ⅵ)的研究

Removing Cr(Ⅵ) from Electroplating Wastewater by Amino-functionalized Magnetic CoFe_2O_4/Graphene Oxide

使用改良的hummers法制备出的氧化石墨烯为载体,采用共沉淀法制备出磁性CoFe_2O_4/氧化石墨烯(MGO),再使用三乙烯四胺(TETA)对磁性CoFe_2O_4/氧化石墨烯进行氨基功能化,制备出氨基功能化磁性CoFe_2O_4/氧化石墨烯吸附剂。采用X-射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)和扫描电子显微镜(SEM)对TETA-MGO的物相、化学组成和微观形貌进行表征,以TETA-MGO作为吸附剂去除电镀废水中Cr(Ⅵ),探讨吸附性能和吸附机理,分析TETA-MGO在外加磁场下的液固分离和再生吸附性能。结果表明纳米级立方尖晶石相磁性CoFe_2O_4均匀生长于氧化石墨烯的表面和片层之间,TETA通过C-N键与磁性氧化石墨烯(MGO)相连,氨基功能化成功,活性吸附位点增点。室温下,p H=2时吸附效果最佳,吸附120 min时达到吸附平衡,平衡吸附量约为48. 66 mg·g-1,TETA-MGO对Cr(Ⅵ)的吸附动力学和吸附热力学可分别使用拟二级动力学模型和Langmuir等温吸附模型描述,吸附过程主要属于化学吸附控制的单分子层吸附,使用外加磁场可以对TETA-MGO实现简单的固液分离,TETA-MGO经过6次再生吸附后,对Cr(Ⅵ)的吸附量仅下降19. 67%,说明具有良好的循环再生吸附能力。

With graphene oxide that obtained by modified hummers method as carrier,the magnetic CoFe2O4/Graphene oxide( MGO) was prepared using chemical co-precipitation,then adding modified reagent Triethylene tetramine( TETA) to synthesize the amino-functionalized magnetic CoFe2O4/Graphene oxide( TETA-MGO). The structure,chemical constitution and micromorphologies of TETA-MGO were characterized by X-ray diffraction( XRD),Fourier transform Infrared spectrum( FT-IR) and Scanning electron microscope( SEM). The adsorption property and adsorption mechanism were investigated with TETA-MGO as adsorbent to remove the Cr( Ⅵ) in electroplating wastewater,so as to solid separation property from liquid and regeneration performance were studied. Cubic spinel phase nanoparticle uniformly grow on the surface and the inside of graphene oxide lamella,the MGO are successful functionalized by TETA that connect with MGO by C-N bond,and activated adsorption site increase. At the room temperaturethe,the optimized adsorption capacity can reach 48. 66 mg·g^-1 when adsorptionequilibrium obtained at about 120 min and pH is 2, the adsorption mechanism of Cr( Ⅵ) in electroplating wastewater on the TETA-MGO is chemical monolayer adsorption owing to the adsorption kinetics and adsorption thermodynamics is mainly tally with the pseudo-second-order kinetics model and Langmuir isotherm model. the TETA-MGO solid can separate from liquid under the magnetic field. The adsorption amount of Cr( Ⅵ) merely decrease 19. 67% regenerating 6 times,which indicate TETA-MGO possesses stable performance of regenerative adsorption.