PVA/GA/β-CD纳米纤维的制备及染料吸附性能

利用静电纺丝技术,以六氟异丙醇(HFIP)和水为溶剂,制备了环糊精(β-CD)含量为70%(质量分数)的聚乙烯醇(PVA)/β-CD纳米纤维,并经戊二醛(GA)交联处理得到了可用于染料吸附的PVA/GA/β-CD纳米纤维.通过红外光谱和扫描电子显微镜研究了交联反应前后纳米纤维组成和形貌的变化;考察了PVA/GA/β-CD纳米纤维对7种水溶性染料的吸附性能.结果表明,PVA/GA/β-CD纳米纤维对孔雀石绿、甲基紫和刚果红的吸附效果较好,最大吸附量分别为124.71,121.14和127.39 mg/g,4次吸附-解吸附循环后,染料去除率仍保持80%左右,在染料废水处理中具有良好的应用前景.     

伤科黄水/聚乙烯醇静电纺丝纳米纤维创面敷料的制备及其性能北大核心CSCD

浸有中药伤科黄水的纱布处理伤口,药效短,需要反复用药,且易与伤口粘连,无法在吸收伤口分泌物的同时防止水分和电解质的流失等,限制了伤科黄水的应用和效果。针对上述问题,以超亲水高分子聚乙烯醇(PVA)为原料,通过高压静电纺丝,制备了一种担载伤科黄水的聚乙烯醇静电纺丝纳米纤维创面敷料。该创面敷料具有良好的机械性能、吸液能力和药物缓释功能,细胞毒性实验中,伤科黄水/PVA静电纺丝纳米纤维膜组的细胞存活率均在75%以上;其中,PVA质量分数为10%、黄水质量分数为2%的静电纺丝纤维膜,具有较高的拉伸强度和弹性模量,且具有良好的延展性和吸收渗出液能力,吸液能力可达自身重量的8倍以上。大鼠皮肤全层缺损修复实验中,该组创面敷料的愈合速度和创面修复效果明显优于伤科黄水原药组及其它低药物含量组。该伤科黄水/PVA静电纺丝纳米纤维膜可作为一种良好的创面覆盖物,吸收创口渗出、加速皮肤缺损修复,在拓宽院内制剂中药伤科黄水的应用形式和增强其使用效果等方面具有十分广阔的前景。     

静电纺丝制备杯芳烃功能化纳米纤维的应用

静电纺丝技术是制备连续微纳米纤维的一种简单易行且高效的方法,所制备的纳米纤维因其独特的结构尺寸和广泛的应用领域而备受材料科学界的青睐。 作为第三代超分子主体化合物的杯芳烃及其衍生物因其独特的分子结构、优异的离子选择识别性和吸附性能而显示出广阔的应用前景。 本文简述了静电纺丝制备杯芳烃功能化纳米纤维的原理,系统地探讨了其作为吸附剂和催化剂载体的应用以及静电纺丝与杯芳烃相结合的优势。 讨论了目前静电纺丝制备杯芳烃功能化纳米纤维存在的问题,对未来的发展方向进行展望。     

钯/聚乙烯醇纤维膜催化水相中的Heck偶联反应

通过静电纺丝和热交联技术、以聚乙烯醇( PVA)作为载体制备了一种电纺纤维膜负载型钯催化剂.利用扫描电镜(SEM)、能谱仪(EDS)和X射线光电子能谱(XPS)对其进行了表征.SEM结果显示:PdCl2的加入导致PVA纤维直径增加、形貌变差,而热交联过程可以减小纤维直径、改善纤维形貌.XPS表征则表明PVA可以还原pd...     

恩诺沙星分子印迹纳米纤维膜的制备及性能

通过沉淀聚合法制备了恩诺沙星（ENRO）分子印迹聚合物（MIPs）微球,将其添加到聚乙烯醇（PVA）溶液中,采用静电纺丝技术制备了恩诺沙星分子印迹纳米纤维膜（MINFMs）. 利用扫描电子显微镜（SEM）研究了纺丝液浓度、纺丝电压及接收距离对MINFMs纤维直径及表面形貌的影响,从溶胀性、孔隙率、吸附容量及吸附选择性等几个方面对印迹膜的性能进行了评价. 结果表明,在环境温度25 ℃、相对湿度 40%~50%、MIPs加入量8%（质量分数）、PVA质量分数7%、纺丝电压15 kV和接收距离25 cm的条件下,得到的MINFMs的纤维形态良好,纤维平均直径为180 nm. MINFMs的溶胀度和孔隙率分别为136.76%和33.42%,均大于非印迹纳米纤维膜（NINFMs）. 动力学吸附性能结果显示,MINFMs在300 min后吸附基本达到平衡,且明显高于NINFMs的吸附量;Scatchard分析结果表明,在所研究的浓度范围内MINFMs对模板ENRO的结合位点是等价的,其离解平衡常数（K_d）与最大表观结合量（Q_max）分别为505.817 mg/L和3.862 mg/g. 与环丙沙星（CIP）和氧氟沙星（OFL）相比,MINFMs对ENRO表现出更强的特异性吸附能力.     

静电纺丝法制备新型吸附分离材料

随着现代经济、工业的发展,许多环境问题出现在了人类面前,对于新型吸附分离材料的需求也变得十分迫切。静电纺丝法是一种简单有效制备连续纳米长丝的技术,有着十分广阔的应用前景。由于静电纺丝法制备的纤维膜具有较大的比表面积、易于调控的微观结构及化学性质,静电纺丝法能够用于制备新型的吸附分离材料。本文对电纺纤维膜的制备与改性,以及电纺纤维膜在空气过滤、油水分离、重金属离子去除等领域的应用进行了介绍,同时对其未来的发展进行了展望。     

静电喷雾结合热压处理制备荷负电PVA-SA/PAN纳米纤维基复合滤膜及其纳滤性能研究

以静电纺丝聚丙烯腈(PAN)纳米纤维作为多孔支撑层,以亲水材料聚乙烯醇(PVA)和海藻酸钠(SA)为亲水表层材料,通过静电喷雾技术将亲水表层材料沉积在纳米纤维多孔基膜表面,然后将表层PVA-SA纳米串珠层通过水蒸气加湿辅助热压成膜处理在PAN基膜上软化压延形成完整的致密薄膜,最后经过戊二醛交联制备PVA-SA/PAN纳米纤维基复合滤膜.通过对加湿时间、热压温度、热压时间以及PVA-SA静电喷雾时间等成膜工艺条件和交联条件进行优化制备出结构完整的PVA-SA/PAN纳米纤维基复合滤膜.所制备的复合滤膜荷负电,它对阴离子染料具有较好的过滤效果:在0.6 MPa的操作压力下对100 mg/kg的固绿染料的渗透通量为57.1 L/(m~2h),截留率为96.8%.     

PVA微晶交联和SA/PAA双网络协效增强增韧SA纤维

为了提高海藻酸钠(SA)纤维的断裂强度和断裂伸长率, 以丙烯酸(AA)为化学交联组分, SA为离子交联组分, 聚乙烯醇(PVA)为微晶交联组分, 采用湿法纺丝和冻融循环方法制备含有PVA微晶交联点和海藻酸钠/聚丙烯酸(SA/PAA)双网络结构的海藻酸钠/聚丙烯酸/聚乙烯醇(SA/PAA/PVA)复合纤维. 通过流变性能、 力学性能、 红外光谱、 X射线衍射仪(XRD)和扫描电子显微镜(SEM)测试研究了交联剂N,N-亚甲基双丙烯酰胺(MBA)含量和PVA微晶交联对SA/PAA/PVA纺丝原液和复合纤维的结构与性能的影响. 结果表明, 当MBA质量分数为0.5%时, 纺丝原液的损耗模量(G″)最小, 可纺性最好, 复合纤维的断裂强度达到2.83 cN/dtex, 断裂伸长率达到9.38%, 比再生SA纤维分别提高了15.98%和38.96%; PVA冷冻之后形成微晶交联点并且PAA和PVA已经复合到体系中; PAA和PVA的加入提高了复合纤维的结晶度; 复合纤维的表面形貌趋于光滑和规整, 纤维断面更加致密.     

改性海藻酸钠聚集行为对电纺纳米纤维形貌的影响

以过硫酸钾(KPS)为引发剂, 采用双丙酮丙烯酰胺(DAA)对海藻酸钠(SA)进行改性, 制备了海藻酸钠-聚双丙酮丙烯酰胺两亲性共聚物(SA-PDAA). 将SA-PDAA与聚乙烯醇(PVA)复配, 并进行静电纺丝, 制得SA-PDAA/PVA电纺纳米纤维. 通过红外光谱、 差示扫描量热和荧光光谱表征了SA-PDAA的结构和性能, 通过黏度仪、 表面张力仪和电导率仪测试了SA-PDAA纺丝液的物理性能, 用扫描电子显微镜表征了SA-PDAA/PVA电纺纳米纤维的形貌, 考察了SA-PDAA/PVA电纺纳米纤维的释药性能. 结果表明, DAA接枝到SA分子链上, SA-PDAA的临界聚集浓度为0.072 g/L, SA-PDAA具有良好的两亲性, SA-PDAA/PVA电纺纳米纤维具有均一的形貌. 改性后的SA可以有效地减缓药物释放速度, 提高SA-PDAA/PVA电纺纳米纤维的缓释性能.     

魔芋葡甘聚糖/聚乙烯醇纳米纤维膜及其释药行为研究

为了研制药物缓释效果优良的薄膜材料,利用静电纺丝设备研制不同比重的魔芋葡甘露聚糖/聚乙烯醇纳米纤维膜,并通过扫描电镜、傅里叶变换红外光谱和示差扫描量热法表征纳米纤维膜的结构和性能,结合体外实验和数学模型研究其缓释行为.结果显示当魔芋葡甘露聚糖含量占纳米纤维膜总质量约76%时,纳米纤维膜中微纤丝粗细最均匀且结点较少,纳米纤维膜中魔芋葡甘聚糖和聚乙烯醇之间存在明显的相互作用,含有5-氨基水杨酸的纳米纤维膜在pH=7.4 PBS磷酸盐缓冲液中25 h的累积释放量大约为45%,显示出良好的药物缓释效果,其缓释行为与Higuchi模型具有较高的拟合度.研究表明利用静电纺丝设备研制的魔芋葡甘聚糖/聚乙烯醇纳米纤维膜可以为药物缓释载体的开发提供理论依据.     

Folic acid modified electrospun poly(vinyl alcohol)/polyethyleneimine nanofibers for cancer cell capture applications

Capture and detection of metastatic cancer cells are crucial for diagnosis and treatment of malignant neoplasm. Here, we report the use of folic acid (FA) modified electrospun poly(vinyl alcohol) (PVA)/polyethyleneimine (PEI) nanofibers for cancer cell capture applications. Electrospun PVA/PEI nanofibers crosslinked by glutaraldehyde vapor were modified with FA via a poly(ethylene glycol) (PEG) spacer, followed by acetylation of the fiber surface PEI amines. The formed FA-modified nanofibers were well characterized. The morphology of the electrospun PVA/PEI nanofibers is smooth and uniform despite the surface modification. In addition, the FA-modified nanofibers display good hemocompatibility as confirmed by hemolysis assay. Importantly, the developed FA-modified nanofibers are able to specifically capture cancer cells overexpressing FA receptors, which were validated by quantitative cell counting assay and qualitative confocal microscopy analysis. The developed FA-modified PVA/PEI nanofibers may be used for capturing circulating tumor cells for cancer diagnosis applications.     

Critical Evaluation of Adsorption–Desorption Hysteresis of Heavy Metal Ions from Carbon Nanotubes: Influence of Wall Number and Surface Functionalization

Single‐, double‐, and multi‐walled carbon nanotubes (SWCNTs, DWCNTs, and MWCNTs), and two oxidized MWCNTs with different oxygen contents (2.51 wt % and 3.5 wt %) were used to study the effect of the wall number and surface functionalization of CNTs on their adsorption capacity and adsorption–desorption hysteresis for heavy metal ions (Ni^II, Cd^II, and Pb^II). Metal ions adsorbed on CNTs could be desorbed by lowering the solution pH. Adsoprtion of heavy metal ions was not completely reversible when the supernatant was replaced with metal ion‐free electrolyte solution. With increasing wall number and amount of surface functional groups, CNTs had more surface defects and exhibited higher adsorption capacity and higher adsorption–desorption hysteresis index (HI) values. The coverage of heavy metal ions on the surface of CNTs, solution pH, and temperature affect the metal ion adsorption–desorption hysteresis. A possible shift in the adsorption mechanism from mainly irreversible to largely reversible processes may take place, as the amount of metal ions adsorbed on CNTs increases. Heavy metal ions may be irreversibly adsorbed on defect sites.     

Phosphorylated polyacrylonitrile‐based electrospun nanofibers for removal of heavy metal ions from aqueous solution

The phosphorylated polyacrylonitrile‐based (P‐PAN) nanofibers were prepared by electrospinning technique and used for removal of Cu²⁺, Ni²⁺, Cd²⁺, and Ag⁺ from aqueous solution. The morphological and structural properties of P‐PAN nanofibers were characterized by scanning electron microscope and Fourie transform infrared spectra. The P‐PAN nanofibers were evaluated for the adsorption capacity at various pH, contact time, and reaction temperature in a batch system. The reusability of P‐PAN nanofibers for the removal of heavy metal ions was also determined. Adsorption isotherms and adsorption kinetics were also used to examine the fundamental adsorption properties. It is found that the P‐PAN nanofibers show high efficiency, and the maximal adsorption capacities of metal ions as calculated from the Langmuir model were 92.1, 68.3, 14.8, and 51.7 mg/g, respectively. The kinetics of the heavy metal ions adsorption were found to follow pseudo‐second‐order rate equation, suggesting chemical adsorption can be regarded as the major factor in the adsorption process. Sorption/desorption results reveal that the obtained P‐PAN nanofibers can remain high removal efficiency after four cycles.     

交联羧甲基魔芋葡甘聚糖吸附重金属离子的研究

以异丙醇为分散剂,环氧氯丙烷为交联剂,在碱性介质中由一氯乙酸和魔芋葡甘聚糖(KGM)反应,制备了取代度为0.265和0.550的两种交联羧甲基魔芋葡甘聚糖(CMKGM),并将其用于吸附溶液中Cu2 、Pb2 和Cd2 。结果表明,CMKGM对3种重金属离子的吸附约在20min内达到平衡,与金属离子类型无关,吸附遵从二级动力学方程;pH对吸附量影响较大,适宜范围为5~6;吸附能较好地服从Langmuir等温吸附方程,CMKGM(DS=0.550)吸附Pb2 的最大吸附容量(Qm)为41.7mg/g,Langmuir常数(b)为0.305mg/L,均大于Cu2 和Cd2 相应值;再生后的CMKGM吸附性能好,脱吸附百分率高。     

Improved cellular response on multiwalled carbon nanotube-incorporated electrospun polyvinyl alcohol/chitosan nanofibrous scaffolds

We report the fabrication of multiwalled carbon nanotube (MWCNT)-incorporated electrospun polyvinyl alcohol (PVA)/chitosan (CS) nanofibers with improved cellular response for potential tissue engineering applications. In this study, smooth and uniform PVA/CS and PVA/CS/MWCNTs nanofibers with water stability were formed by electrospinning, followed by crosslinking with glutaraldehyde vapor. The morphology, structure, and mechanical properties of the formed electrospun fibrous mats were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and mechanical testing, respectively. We showed that the incorporation of MWCNTs did not appreciably affect the morphology of the PVA/CS nanofibers; importantly the protein adsorption ability of the nanofibers was significantly improved. In vitro cell culture of mouse fibroblasts (L929) seeded onto the electrospun scaffolds showed that the incorporation of MWCNTs into the PVA/CS nanofibers significantly promoted cell proliferation. Results from this study hence suggest that MWCNT-incorporated PVA/CS nanofibrous scaffolds with small diameters (around 160 nm) and high porosity can mimic the natural extracellular matrix well, and potentially provide many possibilities for applications in the fields of tissue engineering and regenerative medicine.     

Application of Crosslinked Ionic Poly(Vinyl Alcohol) Nanogel as Adsorbents for Water Treatment

Core-shell smart ionic nanogels based on poly(vinyl alcohol) (PVA) core and poly(N-isopropylacrylamide/acrylic acid) p(NIPAm-AAc) shell particles were successfully synthesized through a one-step surfactant-free emulsion polymerization method (SFEP). Different mole ratios of p(NIPAm-AAc) shells were synthesized. The morphologies of PVA/p(NIPAm-AAc) nanogels were investigated by transmission electron microscope (TEM). The data showed the formation of spherical nanoparticles and well-defined core-shell nanogels. PVA/p(NIPAm-AAc) core-shell nanogels were applied as a novel polymeric adsorbent to remove heavy metal pollutants from aqueous solution. Copper(II) (Cu²⁺) ions were selected as the target pollutant to evaluate these nanoparticles’ adsorption capability. The influence of the uptake conditions such as pH, weight ratio of nanoparticles, time, initial feed concentration, and adsorption temperature on the metal ion binding capacity of nanogels was also tested. Adsorption equilibrium data were calculated according to Langmuir and Freundlich isotherms. It was found that the sorption of Cu²⁺ was better suited to the Freundlich adsorption model than the Langmuir adsorption model. Also, the selectivity of the nanogels toward the different metal ions such lead (Pb²⁺) and cadmium (Cd²⁺) were tested. The maximum of Cu²⁺ ions adsorbed on to PVA/p(NIPAm-AAc) core-shell nanogels adsorbent was 94 mg/g obtained under simple and fast experimental conditions, indicating these nanogels can be used as effective and practical polymeric adsorbents.     

水杨酸型螯合树脂对Fe(III)离子的螯合吸附行为

以5-氨基水杨酸(ASA)为胺化试剂, 使氯甲基化的交联聚苯乙烯(CMCPS)微球表面的苄氯基团发生亲核取代反应, 制得了水杨酸型螯合树脂ASA-CPS. 研究了该螯合树脂对金属离子的螯合吸附行为, 探讨了其吸附热力学与吸附机理, 考察了介质pH值对树脂螯合吸附性能的影响以及树脂对不同金属离子的螯合吸附能力. 实验结果表明, 水杨酸型螯合树脂ASA-CPS 对重金属离子具有强螯合吸附性能, 尤其对Fe3+离子表现出很强的螯合吸附能力, 常温下吸附容量可达21 g/100 g. 吸附过程属熵驱动的化学吸附过程, 升高温度, 吸附容量增高; 在可抑制金属离子水解的pH范围内, 介质的pH值越高, 螯合吸附能力越强; 对于性质不同的金属离子, ASA-CPS的吸附性能是有差别的, 吸附容量的顺序为Fe3+>Ni2+>Cu2+>Zn2+.     

Enhancing adsorption of heavy metal ions onto biobased nanofibers from waste pulp residues for application in wastewater treatment

Biobased nanofibers are increasingly considered in purification technologies due to their high mechanical properties, high specific surface area, versatile surface chemistry and natural abundance. In this work, cellulose and chitin nanofibers functionalized with carboxylate entities have been prepared from pulp residue (i.e., a waste product from the pulp and paper production) and crab shells, respectively, by chemically modifying the initial raw materials with the 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) mediated oxidation reaction followed by mechanical disintegration. A thorough investigation has first been carried out in order to evaluate the copper(II) adsorption capacity of the oxidized nanofibers. UV spectrophotometry, X-ray photoelectron spectroscopy and wavelength dispersive X-rays analysis have been employed as characterization tools for this purpose. Pristine nanofibers presented a relatively low content of negative charges on their surface thus adsorbing a low amount of copper(II). The copper adsorption capacity of the nanofibers was enhanced due to the oxidation treatment since the carboxylate groups introduced on the nanofibers surface constituted negative sites for electrostatic attraction of copper ions (Cu²⁺). The increase in copper adsorption on the nanofibers correlated both with the pH and carboxylate content and reached maximum values of 135 and 55 mg g^?1 for highly oxidized cellulose and chitin nanofibers, respectively. Furthermore, the metal ions could be easily removed from the contaminated nanofibers through a washing procedure in acidic water. Finally, the adsorption capacity of oxidized cellulose nanofibers for other metal ions, such as nickel(II), chromium(III) and zinc(II), was also demonstrated. We conclude that TEMPO oxidized biobased nanofibers from waste resources represent an inexpensive and efficient alternative to classical sorbents for heavy metal ions removal from contaminated water.     

Biocompatible Crosslinked Nanofibers of Poly(Vinyl Alcohol)/Carboxymethyl‐Kappa‐Carrageenan Produced by a Green Process

This study presents a new type of biocompatible nanofiber based on poly(vinyl alcohol) (PVA) and carboxymethyl‐kappa‐carrageenan (CMKC) blends, produced with no generation of hazardous waste. The nanofibers are produced by electrospinning using PVA:CMKC blends with ratios of 1:0, 1:0.25, 1:0.4, 1:0.5, and 1:0.75 (w/w PVA:CMKC) in aqueous solution, followed by thermal crosslinking. The diameter of the fibers is in the nanometer scale and below 300 nm. Fourier transform infrared spectroscopy shows the presence of the carboxyl and sulfate groups in all the fibers with CMKC. The nanofibers from water‐soluble polymers are stabilized by thermal crosslinking. The incorporation of CMKC improves cytocompatibility, biodegradability, cell growth, and cell adhesion, compared to PVA nanofibers. Furthermore, the incorporation of CMKC modulates phenotype of human adipose‐derived stem cells (ADSCs). PVA/CMKC nanofibers enhance ADSC response to osteogenic differentiation signals and are therefore good candidates for application in tissue engineering to support stem cells.     

A Novel Hollow Carbon@MnO2 Electrospun Nanofiber Adsorbent for Efficient Removal of Pb2+ in Wastewater

Lead ion(Pb²⁺) is one of the most hazardous heavy metal ions in aquatic environments. Carbon materials and manganese dio-xide(MnO₂) have been shown to be prospective adsorbents to cope with the lead pollution. In this study, a novel hollow carbon@MnO₂ composite nanofiber adsorbent was prepared by the combination of electrospinning and carbonization. The PAN nanofiber membrane is subjected to a pre-oxidation and carbonization process, and then the obtained carbon nanofibers react with KMnO₄ solution during the hydrothermal process to develop the hollow carbon@MnO₂ nanofibers. The hollow carbon@MnO₂ nanofibers displayed a higher adsorption capacity of Pb²⁺ than carbon and MnO₂/PDA/PAN nanofibers. The maximum adsorption capacity toward Pb²⁺ by hollow carbon@MnO₂ nanofibers was 460.83 mg/g. After 5 adsorption-desorption cycles, the carbon@MnO₂nanofibers had a good recyclability and the removal efficiency remained 81.47%. Moreover, the removal efficiency of the hollow composite nanofibers for Pb²⁺ from real wastewater could reach 94.37%. This work shows a strategy for synthetics of the hollow carbon@MnO₂ nanofibers, which exhibits a promising potential in actual wastewater treatment.