TPU纳米纤维膜对典型内分泌干扰素的吸附去除

利用静电纺丝技术成功制备了热塑性聚氨酯（TPU）纳米纤维膜（TPU-NFM）,通过扫描电镜、傅里叶变换红外光谱对TPU-NFM进行表征,并设置了动力学实验和热力学实验研究TPU-NFM对BPA、EE2的吸附性能及吸附机理,探讨了环境条件对膜吸附的影响.结果表明：静电纺丝TPU纳米纤维光滑纤细、直径均匀、有良好的网状结构以及丰富的表层基团.吸附实验表明TPU-NFM对BPA的吸附过程符合Langmuir模型和准二级动力学模型,吸附过程中单分子层的化学吸附占主导作用,最大吸附容量q_max=45.48mg/g,最大吸附速率k₂=0.754g/（mg·h）.对EE2的吸附过程符合Langmuir模型和Elovich模型,偏向各吸附机理综合作用的结果,其q_max=38.22mg/g,初始吸附速率a=5.355mg/（g·h）.此外,TPU-NFM对环境中盐度以及pH值的敏感度不高.     

静电纺丝纤维膜固定化漆酶对水中双酚A的降解性能

采用乳液静电纺丝技术原位固定漆酶,利用扫描电子显微镜(SEM)和激光共聚焦扫描显微镜(LCSM)对载漆酶电纺纤维膜的形貌结构进行表征.载酶电纺纤维呈壳-核结构,平均直径为(650±30)nm,表面有许多纳米级孔道;漆酶被成功包埋固定于纤维内部,且保留了79.8%的酶催化活性.以双酚A(Bisphenol A,BPA)为目标污染物,对比电纺纤维膜固定化漆酶和游离漆酶对BPA的降解性能,考察p H值和温度等因素对BPA降解效率的影响.研究结果表明:在优化条件下,电纺纤维膜固定化漆酶对BPA的降解率达80%左右;与游离漆酶相比,固定化漆酶对p H值和温度均表现出更好的耐受性.这主要是因为漆酶被包埋在纤维内部,纤维的聚合物外壳结构可以保护漆酶,减少外界环境对漆酶的影响,而纤维表面的多孔结构可以为漆酶与BPA的接触反应提供通道.     

Super effective Zn-Fe-doped TiO2 nanofibers as photocatalyst for ammonia borane hydrolysis

In this study, the photocatalytic activity of TiO₂ nanofibers toward ammonia borane hydrolysis has been strongly modified by doping the nanostructure by ZnO and Fe₂O₃ oxides. Due to the differences in the work function and band gap energy among the three semiconductors (TiO₂, ZnO and Fe₂O₃), illumination of TiO₂ leads to accumulate the electrons and holes on the conduction and valance bands of Fe₂O₃ and ZnO, respectively. Accordingly, the experimental results indicated that the surface of the obtained nanofibers is very active which results in an instant hydrolysis of ammonia borane molecules reaching the active zone surrounding the nanofibers. Moreover, negative activation energy was determined as increasing the temperature led to decrease the photocatalytic performance. Furthermore, kinetic studies indicated that the heterogeneous catalytic reaction describing the ammonia borane hydrolysis process is zero order which additionally supports the super activity of the introduced nanofibers. It was also observed that Fe₂O₃ content in the introduced nanofibers has distinct influence as the best performance was obtained at 1 wt%. The modified TiO₂ nanofibers were prepared by calcination of electrospun nanofibers composed of titanium isopropoxide, zinc acetate and iron acetate in air at 700 °C for 1 h. Overall, the present study opens a new avenue to overcome the fast electrons/holes recombination dilemma facing TiO₂-based nanostructures.     

硼-氮共掺杂中空碳纳米纤维的制备及其活化过一硫酸盐降解双酚A的性能研究

碳材料由于良好的稳定性、无二次污染、高的比表面积等特性,近年来作为催化剂广泛应用于水处理领域.本文以金属有机骨架（MOFs）材料作为前驱体,通过"静电纺丝+热解"的方法制备了硼-氮共掺杂的中空碳纳米纤维（B-HCNFs）,并利用X射线光电子能谱仪（XPS）、拉曼光谱仪（Raman）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、氮气吸附仪等对制备材料的组成和结构进行了详细的分析.将合成的B-HCNFs用于催化剂活化过一硫酸盐（peroxymonosulfate,PMS）降解双酚A（BPA）,结果表明制备的催化剂具有优异的性能.考察了B掺杂前后以及催化剂投加量、初始pH、温度等因素对BPA去除效率的影响,发现B掺杂可以有效提升催化剂的性能.此外,自由基淬灭实验和电子顺磁共振波谱仪（EPR）研究表明,非自由基（电子转移中间体）在BPA的降解过程中占主导作用,而自由基（SO₄^·-,^·OH）贡献较小.动态循环实验显示该催化剂具有良好的稳定性和应用前景.     

Biodegradation of Electrospun Poly-(ɛ-caprolactone) Non-woven Fabrics by Pure-Cultured Soil Filamentous Fungi

The biodegradation of electrospun nano-fibers of poly(-caprolactone) (PCL) was initially investigated with respect to the environmental application of PCL non-woven fabrics, using pure-cultured soil filamentous fungi, Aspergillus oryzae, Penicillium caseicolum, P. citrinum, Mucor sp., Rhizopus sp., Curvularia sp., and Cladosporium sp. Three kinds of non-woven PCL fabrics with different mean fiber diameters (330, 360, and 510 nm) were prepared by changing the viscosities of the pre-spun PCL solutions (150, 210, and 310 cPs, respectively). All of the pure-line soil filamentous fungi tested grew on the two fiber materials. Electron microscopy was used to observe the biodegradation processes revealing remarkable growth of two fungi, Rhizopus sp. and Mucor sp., along with the accompanying collapse of the nano-fiber matrices. In the biochemical oxygen demand (BOD) test, the biodegradation of the 330 nm PCL nano-fibers by Rhizopus sp. and Mucor sp. exceeded 20 and 30% carbon dioxide generation, respectively. The biodegradability of the PCL non-woven fabrics decreased with the mean fiber diameter and the 330 nm PCL nano-fiber that was made from 150 cPs solution (concentration, 7 wt%) exhibited the highest biodegradability. These results might offer some clues for the applications of the PCL non-woven fabrics having the controlled biodegradability in the environmental uses.     

铁氧化物/壳聚糖复合纳米纤维的制备及吸附五价砷研究

采用高压静电纺丝方法,制备了新型铁氧化物/壳聚糖复合纳米纤维砷吸附剂.扫描电子显微镜(SEM)观察结果显示,该纳米纤维的平均直径为(158±24)nm.X射线衍射谱图(XRD)表明,该纳米纤维为无定形结构.所制备的吸附剂在弱酸性或中性条件下对砷吸附率大于93%;吸附速率快,100 min内可达到吸附平衡;吸附剂对低浓度砷有很强的吸附亲和力,可将初始浓度为750μg·L-1的砷降低到10μg·L-1以下的安全饮用水水平;中性条件下吸附砷的最大容量为7.1 mg·g-1,吸附等温线符合Freundlich模型;有机质对吸附的影响较小;吸附剂可用低浓度Na OH洗脱再生.研究结果表明,该吸附剂制备方法简单,易分离再生,在饮用水除砷领域有较好的应用前景.     

电动修复联合壳聚糖纳米纤维膜PRB对土壤中菲和芘的去除研究

采用电动修复联合可渗透性反应墙(PRB)技术处理土壤中的菲和芘,以静电纺丝制备的壳聚糖纳米纤维膜为PRB介质,并初步探究了其对电动修复效果的影响。结果表明:壳聚糖纳米纤维膜对菲和芘的吸附动力学同时符合伪一级和伪二级模型,吸附为吸热反应,吸附热力学特征符合Freundlich模型。纯电动方法修复处理土壤中的多环芳烃时效率较低,通过采用0.1 mol/L的Na OH控制阳极p H,并添加非离子型表面活性剂Tween80对电动修复进行优化,优化实验条件下菲和芘的去除率分别可达58.6%和45.9%。在优化实验条件下进行EK-PRB的联合修复,菲和芘的去除率分别达到75.3%和65.7%,证明壳聚糖纳米纤维膜对菲和芘的去除有促进作用。     

CNFM的制备及其协同电动技术修复土壤重金属的研究

首先采用静电纺丝工艺制备壳聚糖纳米纤维膜并优化了其制备条件,将制备的纳米纤维膜协同电动技术对土壤中的重金属（Cu、Cr）进行了修复.结果表明,纳米纤维膜制备的优化条件为：m（壳聚糖CS）/m（聚乙烯醇PVA）为20：80,乙酸质量浓度为20%,混合溶液质量分数为8%;所制备的纳米纤维膜平均直径为37.11nm,对金属的吸附平衡时间为4h.单一的电动修复来处理土壤中的重金属效率较低,Cu和Cr的去除效率仅为34.9%和11.7%;采用电动技术协同壳聚糖纳米纤维膜能显著提高重金属的去除效率,二者的去除效率分别达到了82%和91%.