PLGA/G5-T纳米纤维对重金属离子Hg^(2+)的吸附研究

Study of the Adsorption of Hg^(2+) with Modified PLGA/G5-T Nanofibers

在制革、冶金、电镀、采矿等行业发展过程中,含有重金属离子的废水进入河道和农田,重金属污染越来越受到人们的重视,治理和回收重金属也成为一个亟待解决的难题。其中重金属离子Hg^(2+)被认为是最毒的重金属。为了有效处理含重金属离子Hg^(2+)的废水,将胸腺嘧啶(Thymine)修饰到第五代聚酰胺-胺树状大分子(G5.NH2)表面,得到G5-T,之后将G5-T与聚乳酸羟基乙酸(PLGA)混合并用静电纺丝方法得到PLGA/G5-T混纺纤维,并用傅里叶变换红外光谱(FTIR)、扫描电镜(SEM)等手段对PLGA/G5-T混纺纤维进行了表征,并以电感耦合等离子体发射光谱仪ICP-OES为检测手段,研究PLGA/G5-T对Hg^(2+)的吸附效果。FTIR结果表明,PLGA/G5-T纤维中3 320cm^(-1)处的氨基吸收峰比PLGA/G5上的弱,在1 660cm^(-1)处的酰胺基吸收峰比PLGA/G5强,说明G5.NH2与胸腺嘧啶^(-1)-乙酸成功反应。SEM结果表明,添加了G5-T混纺而得的PLGA/G5-T平均直径为(751±72)nm,纤维形貌均一,表面光滑无粘连,说明G5-T的加入没有破坏纤维的完整性。ICP-OES研究发现,PLGA/G5-T纤维膜对Hg^(2+)的脱除效率明显高于PLGA/G5纤维膜,胸腺嘧啶显著增强了PLGA/G5-T纤维膜对Hg^(2+)的脱除效率;对多种金属离子的吸附实验结果显示,PLGA/G5-T纤维膜对Cu2+,Cd2+和Co2+有微弱的吸附效果,但其对Hg^(2+)吸附效果显著,PLGA/G5-T纤维膜对水溶液中的Hg^(2+)有选择性吸收功能。研究为开发新型Hg^(2+)吸附剂提供了一种新方法。

In the development process of leather industry,metallurgical industry,electroplating industry,mining industry and other industries,wastewater containing heavy metal ions is discharged to the river and farmland,resulting in environmental pollution.Heavy metal pollution has been paid more and more attention.It is an urgent problem to control the pollution and recover heavy metals.Hg2＋is considered to be the most toxic heavy metal.This article studied the modified PLGA/G5-T fibers to treat the Hg2＋wastewater efficiently.In this study,thymine-1-acetic containing carboxyl reacted with G5.NH2 to form G5-T.Then G5-T was mixed with PLGA for subsequent formation of T-modified electrospun PLGA/G5-T nanofibers.The nanofibers were characterized with fourier transform infrared（FTIR）and scanning electron microscope（SEM）,and measured the sorption efficiency and selectivity by inductively coupled plasma-optical emission spectroscopy（ICP-OES）.FTIR results showed that the amino groups absorption peak of PLGA/G5-T nanofibers at 3 320cm-1 was weaker than that of PLGA/G5,the amide groups absorption peak of PLGA/G5-T nanofibers at 1 660cm-1 was stronger than that of PLGA/G5,suggesting that G5.NH2 reacted with thymine-1-acetic successfully.The results from SEM measurements showed that mean diameter of PLGA/G5-T nanofibers was（751±72）nm,and fiber morphology of PLGA/G5-T was uniform,smooth without adhesion.It was concluded that the thymine modification would not appreciably impact the fibrous morphology of PLGA/G5-T nanofibers when compared with the PLGA/G5 nanofibers.It could be found with ICP-OES that Hg2＋removal efficiency of PLGA/G5-T was significantly higher than that of PLGA/G5 fiber membrane.The good performance on Hg2＋removal was due to the enhanced removal efficiency of thymine;absorbing test of various metal ions showed that only a little ion of Cu2＋,Cd2＋and Co2＋was adsorbed on PLGA/G5-T while a lot of Hg2＋ions were adsorbed.It was proven that PLGA/G5-T nanofibers can remove Hg2＋from aqueous solution selectively and efficiently.This study is beneficial to research and development of new Hg2＋adsorbents.