静电纺杯芳烃纤维的制备及其对Pt(Ⅳ)选择性吸附性能

Fabrication and selective adsorption on Pt(Ⅳ)of calixarene electrospun fibers

为选择性吸附贵重金属离子,设计并合成5,17-二氨基-26,28-(1',8'-二氧杂-4',5'-二硫杂正辛烷基)-杯[4]芳烃单体,通过酰胺化法合成杯芳烃聚酰胺酸纺丝液,用静电纺丝法制备杯芳烃聚酰胺酸纤维,再对杯芳烃聚酰胺酸纤维进行热酰亚胺化,制备出杯芳烃聚酰亚胺纤维。采用红外光谱和扫描电镜对纤维进行表征,并研究了纤维对Pt(Ⅳ)、Ag(Ⅰ)、Au(Ⅰ)的选择性吸附性能。结果表明,自制杯芳烃单体已成功引入到杯芳烃聚酰亚胺纤维中,纤维直径为(400±40)nm,它仅对Pt(Ⅳ)有很强的选择性吸附作用,吸附行为符合Langmuir等温吸附模型,纤维对Pt(Ⅳ)的饱和吸附量为3.1 mmol/g。选择性吸附的原因是Pt(Ⅳ)最外层电子排布为5d6,未占满,Pt(Ⅳ)可进入纤维中杯芳烃下缘的1,8-二氧杂-4,5-二硫杂正辛烷基的空腔中,并接受O、S的电子,形成配位吸附。

In order to absorb noble metals ions,calixarene-polyimide（ calixarene-PI） fibers were fabricated by design and synthesis of 5,17-diamino-26,28-（ 1＇,8＇-dioxa-4＇,5＇-dithiaoctane）-calix[4]arene monomer, preparation of calixarene-polyamide acid（ calixarene-PAA） spinning solution by amidation,fabrication of the calixarene-PAA fibers by electrospinning,and preparation of calixarene-PI fibers by thermal imidization on calixarene-PAA fibers. Calixarene-PI fibers were characterized by Fourier transform infrared spectrography and scanning electronic microscopy,and their adsorption on Pt（ Ⅳ）,Ag（ Ⅰ） and Au（ Ⅰ） was studied. FT-IR indicates calix[4]arene monomer is incorporated into calixarene-PI fibers. SEM image shows the diameter of calixarene-PI fiber is（ 400 ± 40） nm. CalixarenePI fibers display strong adsorption on Pt（ Ⅳ） rather than Ag（ Ⅰ） and Au（ Ⅰ）,which fit with Langmuir isothermal adsorption model. The saturated amount of Pt（ Ⅳ） adsorbed by calixarene-PI fibers is3. 1 mmol / g. The electron distribution in the outermost of Pt（ Ⅳ） is 5d6,which indicates the 5d electron layer of Pt（ Ⅳ） is not fully occupied by electrons. Pt（ Ⅳ） can accept electrons of O or S in 1,8-dioxa-4,5-dithiaoctane attached in calixarene-PI fibers. Therefore,the coordinative adsorption between Pt（ Ⅳ）and calixarene-PI fibers can be formed.