等离子引发制备PP基印迹纤维对Cr(Ⅵ)的选择吸附

Selective adsorption of Cr(Ⅵ) by PP-based imprinted fibers prepared by plasma initiation

通过等离子改性和离子印迹技术制备聚丙烯(PP)基Cr(Ⅵ)印迹纤维并进行表征,考察了印迹纤维吸附Cr(Ⅵ)过程中的影响因素,并与非印迹纤维的吸附效果进行对比。傅里叶红外光谱和亲水性分析结果表明PP纤维上成功接枝了丙烯酸(AA)和三乙烯四胺(TETA)单体,制得I-PP-g-AA-TETA印迹纤维。印迹纤维对Cr(Ⅵ)的吸附量随pH的增加先略增大后降低,在pH=3时达到最高167 mg/g。印迹纤维对Cr(Ⅵ)的吸附速率很快,35 min时即可达到饱和。随Cr(Ⅵ)平衡浓度增大,印迹纤维对Cr(Ⅵ)的吸附量先增大后平缓,吸附过程符合准二级动力学模型,吸附等温线更接近Freundlich模型。与非印迹纤维相比,印迹纤维在竞争离子存在时对Cr(Ⅵ)具有较好的吸附选择性,Scatchard模型拟合结果表明印迹纤维同时存在特异性和非特异性结合位点,印迹纤维存在Cr(Ⅵ)特异性空腔且这种特异性能够加强纤维和离子的相互作用。

Polypropylene(PP)-based Cr(Ⅵ) imprinted fibers were prepared by plasma modification and ionimprinting technology,and then were characterized.The influence factors in Cr(Ⅵ) adsorption process were investigated,and its adsorption effect was compared with non-imprinted fibers.The results of Fourier transform infrared spectroscopy and hydrophilicity analysis showed that acrylic acid(AA) and triethylenetetramine(TETA) monomers were successfully grafted onto PP fiber to prepare I-PP-g-AA-TETA imprinted fiber.The adsorption capacity of imprinted fibers for Cr(Ⅵ) increased slightly and then decreased with the increase of pH,reaching a maximum of 167mg/g at pH=3.The adsorption rate of Cr(Ⅵ) on imprinted fibers was very fast,reaching saturation after 35 minutes.With the increase of equilibrium concentration of Cr(Ⅵ),the adsorption capacity of imprinted fiber for Cr(Ⅵ) increased first and then became smooth.The adsorption process followed the pseudo-second order kinetic model,and the adsorption isotherm was closer to the Freundlich model.Compared with the non-imprinted fiber,the imprinted fiber had better adsorption selectivity to Cr(Ⅵ) in the presence of competitive ions.The Scatchard model fitting results showed that the imprinted fiber had both specific and non-specific binding sites,indicating that the imprinted fiber had a Cr(Ⅵ) specific cavity and this specificity could enhance the interaction between the fiber and ions.