选择性吸附Pt(Ⅳ)的杯芳烃纤维制备及其吸附动力学

为制备含杯芳烃的新型选择性吸附纤维,首先通过酰胺化和静电纺丝技术制备杯芳烃聚酰胺酸(CPAA)纤维,再将CPAA纤维通过热亚胺化制备得到杯芳烃聚酰亚胺(CPI)纤维,借助红外光谱仪、扫描电子显微镜、热重分析仪分析了纤维的结构和性能,并采用吸附实验研究了纤维的吸附选择性及动力学。结果表明:杯芳烃已引入纤维中,对比CPAA纤维,CPI纤维具有直径更小,主链分解温度更高的优点;CPI纤维可从Pt(Ⅳ)、Ag(Ⅰ)混合溶液中选择性吸附Pt(Ⅳ),溶液pH值为7时吸附量最大,达28 mg/g;CPI纤维吸附Pt(Ⅳ)符合一级动力学特征,20 ℃时吸附速率常数为0.003 9 min^-1,且吸附速率常数随温度升高而增大;CPI纤维易吸附Pt(Ⅳ),吸附所克服的活化能较低,仅为12.24 kJ/mol。

Preparation and adsorption kinetics of calixarene fibers with selective adsorption of Pt(IV)

In order to prepare novel selective adsorption fibers containing calixarene, calixarene polyamide acid (CPAA) fibers were firstly prepared by amidating and electrospinning. Subsequently, the calixarene polyimide (CPI) fibers were obtained by thermal imidization of the CPAA fibers. The CPI and CPAA fibers were characterized by Fourier transform infrared spectrometer, scanning electron microscope and thermogravimetric analysis. The adsorption selectivity and adsorption kinetics of the CPI fibers were also investigated. The results show that calixarene is successfully incorporated into the CPAA and CPI fibers. The CPI fibers possess smaller diameter and higher thermal degradation temperatur by comparison with the CPAA fibers. Only the CPI fibers can adsorb Pt(IV) selectively from the mixture of Pt(IV) and Ag(I). The maximum Pt(IV) absorption capacity of CPI fibers is 28 mg/g at pH 7, and its adsorption behavior fits well with the first-order adsorption kinetics model. The adsorption rate constant is 0.003 9 min^-1 at 20 ℃ and increases with the elevating adsorption temperature. The required activation energy for adsorption is only 12.24 kJ/mol, which indicates the CPI fibers adsorbing Pt(IV) is easy to occur.