改性PAN纳米纤维铁配合物的制备及其催化降解染料性能的比较研究

分别以聚丙烯腈(PAN)纳米纤维和普通PAN纤维为原料,经偕胺肟改性和Fe3+配位反应制备了两种改性PAN纤维铁配合物。考察和比较了偕胺肟改性和Fe3+配位反应中两种纤维的腈基转化率及其配合物中铁含量的变化。然后在表征的基础上分别将两种改性PAN纤维铁配合物作为非均相Fenton反应催化剂应用于偶氮染料活性红195的氧化降解反应中,研究了两者在暗态和可见光辐射条件下的催化降解性能。结果表明,PAN纳米纤维比普通PAN纤维更容易发生偕胺肟改性和Fe3+配位反应。PAN纳米纤维铁配合物对可见光吸收性能略低于普通PAN纤维铁配合物。在染料的氧化降解反应中,PAN纳米纤维铁配合物具有更好的催化活性和稳定性,尤其在暗态时表现得更为突出。     

金属配合纤维对漆酶固定化性能的研究

以静电纺制备的PAN纳米纤维为原料,经偕胺肟基改性后,制得偕胺肟基螯合纳米纤维(AO-PAN),再 利 用AOPAN纳 米 纤 维 上 的 偕 胺 肟 基 与Cu2+ 、Co2+形成配 位键,将Cu2+ 、Co2+固定在AO-PAN纳米纤维上,形成金属配合纳米纤维,最后利用金属配合纤维上的Cu2+ 、Co2+与漆酶形成配位反应,将漆酶固定化。通过红外光谱仪(IR)、扫描电子显微镜(SEM)和透射电子显微镜连接的X射线能谱仪(EDAX)对不同处理阶段的PAN纳米纤维进行了观察分析,并对固定化漆酶的热稳定性、酸碱稳定性、存储稳定性及重复使用性能进行了研究。结果表明,经过配位反应固定的漆酶最适温度为50℃,最适pH值为3,存储稳定性比自由态漆酶高出30%~45%,并且表现出具有一定的可重复使用性。     

固定漆酶对对苯二酚的降解研究

以静电纺制备的PAN纳米纤维为原料,用盐酸羟胺水溶液对其进行化学改性后得到偕胺肟基PAN螯合纳米纤维(AOPAN),将其与Cu~(2+)配位得到金属配合纳米纤维为载体固定漆酶,并研究了固定漆酶对对苯二酚的降解。分别采用红外光谱仪(FT-IR)、扫描电子显微镜(SEM)和能谱仪(EDAX)对不同处理阶段的PAN纳米纤维进行了观察分析,并对固定漆酶的性能进行了研究,通过测定不同降解阶段对苯二酚的吸光度变化来分析其降解情况。结果表明:改性后的PAN纳米纤维表面没有出现严重的裂痕或降解现象。固定漆酶的最适pH值为4,最适温度为50℃。铜离子配合螯合PAN纳米纤维膜(Cu-AOPAN)固定的漆酶,3次重复利用后,对对苯二酚的降解率分别为55.18%、50.75%、50.65%。     

稀土配合物Eu(Ⅲ)、Tb(Ⅲ)纤维的制备及其荧光性能研究

将腈纶纤维(PAN)与羟胺溶液反应,制备偕胺肟腈纶纤维(AOCF);AOCF与EuCl_3和TbCl_3进行反应,制备偕胺肟-Eu(Ⅲ)纤维和偕胺肟-Tb(Ⅲ)纤维,探讨了合成反应的最佳条件参数,得出在pH为3~4、温度为45℃左右时,配合物纤维的颜色变化最深,纤维中Eu(Ⅲ)、Tb(Ⅲ)的含量最高。红外谱图显示,配合物纤维中νN—O、νCN特征峰均发生了位移,峰的强度也有较大变化,表明了Eu(Ⅲ)和Tb(Ⅲ)与偕胺肟纤维发生了配位反应。从配合物纤维的荧光谱图可以看出,在一定的激发波长下,配合物纤维都具有明显的荧光性能。     

偕胺肟化聚丙烯腈-β-环糊精纳米纤维膜的制备及其吸附性能

利用聚丙烯腈(PAN)和β-环糊精(β-CD)原料,采用盐酸羟胺原位偕胺肟改性和静电纺丝技术,一步合成制备出偕胺肟聚丙烯腈(AOPAN)-β-CD纳米纤维膜.以纤维膜的形貌和对铀的吸附量为评价指标,优化了改性制备工艺条件.通过SEM、FTIR、表面张力仪等对纤维的形貌、组成和性能进行表征.结果表明,当氰基与羟胺摩尔比为...     

聚丙烯腈纤维改性条件优化及其对模拟电镀废水的净化作用

为了寻求低价、环保的电镀废水处理方案,将廉价的聚丙烯腈(PAN)纤维与羟胺试剂反应对PAN纤维进行改性,使其上氰基螯合获得偕胺肟基纤维。通过改变各种改性条件,探讨了改性条件对PAN改性纤维在重金属单离子溶液和多离子混合溶液中吸附性能的影响。结果表明:最佳改性条件为21.2 g/L PAN纤维,27.0 g/L盐酸羟胺,pH值为7.0,70℃下反应2 h;改性PAN纤维对模拟电镀废水中的Cu2+,Zn2+,Ni2+,Pb2+,Cd2+等重金属离子均有较好吸附性能,其中对Cd2+吸附效果最好,吸附量为55 mg/g;在多离子混合溶液中优先选择吸附Cd2+;改性PAN纤维再生效果优良,可重复利用。     

PAN纳米纤维的改性及其应用于吸附金属离子

用盐酸羟胺溶液对静电纺聚丙烯腈(PAN)纳米纤维进行化学改性,制得偕胺肟PAN(AOPAN)纳米纤维,并用作吸附金属离子的基材。用SEM、FT-IR对化学改性前后PAN纳米纤维的表面形貌及分子结构进行表征。采用原子吸收分光光度计(AAS)测试溶液中金属离子的浓度,以此研究AOPAN纳米纤维对铜和铁金属离子的吸附性能。结果表明,AOPAN纳米纤维对Fe3+、Cu2+的饱和吸附量分别为206.36mg/g和118.38mg/g,且其吸附过程非常符合Langmuir吸附等温模型。此外,在1mol/L的硝酸溶液中反应60min后,Fe3+、Cu2+的洗脱率分别达到了90.6%和86%。     

交联型偕胺肟型凝胶的制备及对镓离子的吸附性能

以水合联胺为交联剂,利用"热致相分离"原理制备了聚丙烯腈/二甲亚砜(PAN/DMSO)交联(C-PAN)凝胶,将其进一步与羟胺(NH2OH)反应后得到交联型偕胺肟(C-PAO)凝胶,交联型偕胺肟凝胶可用于吸附强碱性模拟拜耳溶液中的镓离子(Ga~(3+))。文中采用了超临界CO_2萃取干燥法取代真空干燥,并探讨了不同溶度参数的交换溶剂对凝胶孔径的影响。红外测试结果表明,凝胶成功偕胺肟化且偕胺肟基团与镓离子发生了螯合作用;扫描电镜照片显示,当交换溶剂的溶度参数与PAN基体的差值(Δδ)增加,得到的凝胶孔径减小;吸附测试结果显示,偕胺肟凝胶对模拟拜耳溶液中镓离子的饱和吸附量为15.8 mg/g,平衡时间为140 min。     

聚丙烯胺肟螯合纤维的合成及性能

采用＾６０Ｃｏ－γ射线预辐照方法合成了聚丙烯胺肟（ＰＰＡＯ）螯合纤维。研究了影响接枝率和胺肟基团含量的因素。结果表明，接枝率随预辐照剂量、单体浓度、反应时间和反应温度的增加而增加。羟胺溶液的ｐＨ＝７时，胺肟基团含量最高。胺肟化反应时间大于１．５ｈ，胺肟基团含量不再增加。该纤维对金的吸附容量为９９．１ｍｇ／ｇ干纤维，对钯和铜也有较好的吸附性能。     

一种含亚胺基的螯合型吸附剂的制备及对钯离子的吸附

为制备一种能螯合钯离子的新型含亚胺基团的吸附剂,首先对聚丙烯无纺布(PP)进行预辐照接枝丙烯腈(AN),然后进一步和二乙烯三胺(EDTA)反应。结果表明,胺化反应时间越长,腈基基团转化为亚胺基团的转化率越高。当温度高于120℃,有一部分聚丙烯溶解于胺化试剂中。考察了吸附时间和钯离子初始浓度对吸附量的影响。结果表明,制备的螯合型吸附剂对钯离子的吸附性能良好。对接枝后和胺化后的样品用红外光谱仪和差示扫描量热仪进行了表征。     

Synthesis of polyacrylonitrile-grafted cross-linked N-chlorosulfonamidated polystyrene via surface-initiated ARGET ATRP, and use of the resin in mercury removal after modification

A novel method of surface modification was developed via iron (III)-mediated atom transfer radical polymerization, with activators regenerated by electron transfer (ARGET ATRP) on the surfaces of polystyrene resin-supported N-chlorosulfonamide groups. The well-defined polyacrylonitrile (PAN) was grafted onto the surfaces of the polystyrene (PS). The graft reaction exhibited first-order kinetics with respect to the polymerization time in the low-monomer-conversion stage. The cyano group of PAN-g-PS was modified by NH(2)OH·HCl to yield amidoxime (AO) groups. The AO groups had been demonstrated to be an efficient Hg-specific sorbent, which can remove Hg(2+) from solutions. No interference arose from common metal ions, such as Pd(2+), Ag(+), and Cu(2+). Three adsorption-desorption cycles demonstrated that this resin is suitable for reuse without any considerable change in adsorption capacity.     

Preparation and adsorption behavior of aminated electrospun polyacrylonitrile nanofiber mats for heavy metal ion removal

Polyacrylonitrile (PAN) nanofiber mats were prepared by electrospinning and they were further modified to contain amidino diethylenediamine chelating groups on their surface via heterogeneous reaction with diethylenetriamine (DETA). The obtained aminated PAN (APAN) nanofiber mats were evaluated for their chelating property with four types of metal ions, namely Cu(II), Ag(I), Fe(II), and Pb(II) ions. The amounts of the metal ions adsorbed onto the APAN nanofiber mats were influenced by the initial pH and the initial concentration of the metal ion solutions. Increasing the contact time also resulted in a monotonous increase in the adsorbed amounts of the metal ions, which finally reached equilibria at about 10 h for Cu(II) ions and about 5 h for Ag(I), Fe(II), and Pb(II) ions. The maximal adsorption capacities of the metal ions on the APAN nanofiber mats, as calculated from the Langmuir model, were 150.6, 155.5, 116.5, and 60.6 mg g(-1), respectively. Lastly, the spent APAN nanofiber mats could be facilely regenerated with a hydrochloric acid (HCl) aqueous solution.     

The effect of the distribution of composition among chains on the properties of polyacrylonitrile precursor for carbon fibre

Co-monomers were introduced at a controlled rate into the reaction vessel in order to control the distribution of composition among the polymeric chains. When acrylate co-monomer, such as methyl acrylate or 2-ethyl hexyl acrylate was slowly fed into the reactor, the reaction time required for copolymerization to reach a fixed conversion was not affected, and the cycling temperature (or the temperature at the onset of the exotherm) during oxidation for polyacrylonitrile (PAN) precursor was slightly shifted to a higher temperature. On the other hand, as itaconic acid (IA) co-monomer was slowly fed into the reactor, the reaction rate of copolymerization was increased, and the cycling temperature could be depressed to a lower temperature due to the IA co-monomer being able to initiate the cycling of the CN groups. The structures (such as crystallinity, crystal size, orientation) and mechanical properties for PAN precursor and its resulting carbon fibre were influenced by the distribution of composition among the chains.     

A novel biomimetic catalyst constructed by axial coordination of hemin with PAN fiber for efficient degradation of organic dyes

A novel biomimetic catalyst was synthesized by supporting hemin onto the amidoximated polyacrylonitrile (PAN) fiber and then used for the oxidative degradation of organic dyes by H₂O₂ activation. SEM, FTIR and XPS results suggested that the OH and NH₂ in amidoxime groups were responsible for hemin immobilization through axial coordination bonds. The fibrous support significantly enhanced the catalytic activity and pH tolerance of pure hemin, and the prepared catalyst also exhibited excellent recycling capability. In addition, the effect of axial ligands on the catalytic mechanism was clarified by employing the modified PAN fiber with amidrazones groups as the support of hemin, and the possible catalytic mechanism was proposed and discussed based on the ESR measurement combined with a series of designed experiments. It is found that OH and NH₂ as axial ligands of hemin might induce H₂O₂ activation through two different pathways, corresponding to the generation of Fe(IV)=O and ^·OH species, respectively.     

Characterization of polyacrylonitrile based carbon nanofiber mats via electron beam processing

The aim of this study was to evaluate the ability of electron beam irradiation to drive stabilization reactions within PAN nanofiber mats to obtain carbon nanofiber mats. PAN nanofiber mats with fiber diameters of 300-400 nm were prepared via an electrospinning method. Electrospun PAN nanofiber mats were stabilized by electron beam irradiation with various doses up to 5,000 kGy. Using the irradiation-stabilized PAN nanofiber mats, carbon nanofibers were obtained by pyrolysis in a tube furnace for 1 h at 1,000 degrees C under an N2 atmosphere. FT-IR analysis indicated that the transformation of C[triple bond]N groups to C==N groups was accelerated by electron beam stabilization. The thermal behavior of the PAN nanofiber mats was studied using DSC and TGA. DSC thermograms showed that the peak temperatures of the exothermic reactions were found to decrease with increasing electron beam irradiation doses. Irradiation-stabilized PAN nanofiber mats were not observed to dramatically decrease in weight between 290 degrees C and 320 degrees C, an observation presumed to be related to cyclization. The char yields of PAN were found to increase with increasing irradiation doses.     

Synthesis and characterization of conductive core-shell polyacrylonitrile-polypyrrole nanofibers

Nonwoven polyacrylonitrile-polypyrrole (PAN-PPy) core-shell nanofiber mats were prepared through the growth of PPy layers on electrospun PAN nanofibers via a two-step vapor-phase polymerization, i.e., the wet-coating of ferric tosylate (FeTos) oxidants on PAN nanofibers followed by exposure to pyrrole monomers in the gas phase. Under the conditions ([FeTos] = 10 wt%, reaction time = 15 min, temperature = 15 degrees C), the PPy polymerization procedure led to both a uniform coating over the PAN surface with an average thickness of 18 nm and cross-linkages among the nanofibers without a noticeable change in the highly porous nanofibrous structures. The oxidant concentration and polymerization time were found to be key parameters for achieving a good nanostructured core-shell fiber mat. FT-IR, XPS, XRD and conductivity measurements confirmed the synthesis of Tos-doped PPy with some degree of crystallinity and a high conductivity.     

紫脲酸铵分光光度法测定复盐法水氯镁石脱水产品中氧化镁

对于水氯镁石的复盐(C6H5NH2·HCl·MgCl2·6H2O)法脱水产品中微量MgO含量的测定,采用了直接测定样品水溶残渣中镁含量而得MgO含量的方法代替传统的间接法,获得了更准确的结果。用紫脲酸铵分光光度法测定了水溶残渣用稀H2SO4溶解后溶液中微量镁,研究了金属镁离子与显色剂的络合比、溶液酸度、显色时间对显色的影响,以及盐酸苯胺阳离子、Fe3+、Zn2+、Ba2+、Ca2+、Ni2+、Co2+等离子对显色的干扰及其消除。并采用修正法消除了显色后残余显色剂对测定镁的影响。结果表明,在镁离子浓度0~2mmol/L范围内,修正吸光度与镁离子浓度呈线性关系,摩尔吸光系数为2.45×102 L/(mol·cm)。加标镁离子的测定结果证明该法具有较高的精密度和准确度（加标回收率近100%）,适合于水氯镁石脱水产品中总MgO含量的准确测定。