有序大孔材料的制备及其应用

本文综述了近年来有序大孔材料的制备及应用.有序大孔材料的制备方法有胶态晶体模板法、生物模板法及其它模板法,重点阐述了用胶态晶体为模板制备有序大孔材料,如大孔金属、大孔无机氧化物、大孔碳、大孔半导体、大孔无机盐、大孔碳/无机氧化物复合物和大孔有机聚合物.用胶态晶体为模板制备有序大孔材料在催化、吸附、分离、传感器、光子晶体和声学等领域有潜在的应用.     

超高交联树脂对苯胺的吸附机理研究

在静态条件下，研究了水溶液中超高交联树脂AM－1和NJ－8及大孔吸附树脂Amberlite XAD－4吸附苯胺的热力学特性，测定了不同温度下的吸附等温线。结果表明，在稀溶液中3种树脂吸附苯胺都符合Langmuir和Freundlich模型，其中AM－1和NJ－8对苯胺的吸附是一个吸热过程；由于AM－1和NJ－8的微孔结构和表面存在酸性基团的吸附中心，对苯胺的吸附是物理吸附和化学吸附共同作用的结果。     

超高交联树脂对苯胺和对硝基苯胺的吸附行为

吸附热力学;化学吸附;超高交联树脂对苯胺和对硝基苯胺的吸附行为     

BINARY COMPETITIVE AND COOPERATIVE ADSORPTION OF AROMATIC COMPOUNDS ON POLYMERIC RESINS

The adsorption behaviors of 2-naphthalenesulfonic acid and aniline on a conventional macroporous resin Amberlite XAD4 and the other two newly-developed hypercrosslinked resins NDA101 and NDA100 were investigated in a single or binary batch system at 293 K and 313 K,respectively.All the adsorption isotherms of 2-naphthalenesulfonic acid and aniline on the test resins in both systems can fit well with the Langmuir equation,indicating that the adsorption is a favorable process.At the identical equilibrium concentration,the amount of aniline adsorbed on polymeric resins in the single system is higher than that in the binary system because of the competitive adsorption between 2-naphthalenesulfonic acid and aniline on the resin surface.However,the uptake amount of 2-naphthalenesulfonic acid in the binary system is markedly larger than that in the single system,which is presumably due to the cooperative effect arisen from the electrostatic interaction between 2-naphthalenesulfonic acid and aniline adsorbed on the resin surface.The simultaneous adsorption system was proven to be helpful for the selective adsorption toward 2-naphthalenesulfonic acid due to its larger selective index.     

海地瓜多糖脱色工艺研究

比较了活性炭、H2O2及大孔树脂对海地瓜多糖的脱色效果。从脱色率及多糖保留率两方面进行考察,树脂D392处理优于活性炭和H2O2,对其脱色工艺进行优化,通过响应面实验建立了数学模型,并确定树脂D392脱色的最优工艺为时间:5h,pH 10,温度:60℃,此时,脱色率达(84.2±0.6)%,多糖保留率为(82.9±1.1)%。研究工作有利于海参多糖品质的提高,为海参多糖后续研究及应用奠定了基础。     

High Loading Pt Core/Carbon Shell Derived from Platinum‐Aniline Complex for Direct Methanol Fuel Cell Application

A novel approach to high loaded Pt core/carbon shell catalyst synthesis from a Pt‐aniline complex was reported. The Pt‐aniline complex was successfully synthesized by irradiating an ultrasound to the hexachloro platinic acid and aniline monomer mixture. The highly viscous nature of aniline leads to reproducible hexagonal plate like Pt‐aniline complex crystals. The chemical composition of the Pt‐aniline complex was identified as [PtCl₂(C₆H₅NH₂)₂] with the help of NMR, XPS, HR ESI‐MS, and TGA analyses. Furthermore, the Pt‐aniline hexagonal plates were sintered at various temperatures like 400 °C, 500 °C, and 700 °C for an hour. This formed the highly dispersed carbon covered Pt nano particles with loading of 80.1 wt %, 81.3 wt %, and 83.4 wt % for HP‐4, HP‐5, and HP‐7, respectively. After supporting it on Vulcan XC‐72, Pt core/carbon shell pyrolyzed at a low temperature showed excellent performance in methanol oxidation reaction. In addition, Pt core/carbon shell prepared at a high temperature revealed excellent tolerance to methanol.     

胺基化超高交联吸附树脂对苯酚和苯胺吸附行为的研究

在超高交联吸附树脂上负载不同胺基后,无论是在非水体系还是在水体系中,树脂对苯酚的吸附选择性大大增强.非水体系中,树脂对苯胺和苯酚的吸附是靠氢键作用,水体系中,树脂对苯酚的吸附是表面吸附和基团吸附综合作用的结果.动态吸附表明,树脂胺基化前(Rf18)树脂与季铵化后(Rs6 ) ,对苯胺和苯酚混合水溶液的动态吸附泄漏曲线差别较大.对Rf18树脂,苯酚首先在14 7BV(床体积)处泄漏,其泄漏液浓度上升很快,在2 12BV处达吸附饱和,苯胺在184BV处才开始泄漏,且其泄漏液浓度上升缓慢;在14 7～184BV之间可收集到苯酚溶液.对Rs6树脂,苯胺先泄漏(17BV处) ,其泄漏浓度很快趋于水平,在4 7BV处达吸附饱和;苯酚在4 4BV处开始泄漏,其泄漏曲线也上升很快,在79BV处趋于水平,在17～4 4BV之间可收集到苯胺水溶液.     

碳纳米管对苯胺的吸附行为

碳纳米管有较大的比表面,有利于用作吸附剂。当前研究主要集中在对气体,尤其是对H2气的吸附。近年来,也有人将碳纳米管应用于环境保护领域,Long等使用碳纳米管除去二恶英,Li等用碳纳米管吸附溶液中的Cd^2 都取得了满意的效果。苯胺类化合物是国家严格控制的一类污染物,使用碳纳米管对苯胺的吸附研究尚未见报道。     

Synergistic Enhancement on the Conductivity of Polyaniline via Copolymerization and Carbon Nanotubes

Polyaniline and aniline/5‐aminoisophthalic acid (AIA) copolymer have been successfully synthesized via oxidation polymerization, as well as their composites containing carbon nanotubes. AIA can benefit the formation of quinoid rings in the aniline polymerization and promote the conductivity of the copolymer. IR and Raman spectra reveal AIA/aniline copolymers have both benzonoid and quinoid rings, as well as their doped structures. Good conductivity of the copolymer could be achieved at high AIA content. Carbon nanotubes can also simultaneously promote the formation of quinoid rings in the copolymer, enhance conductivity and improve thermal stability. The copolymerization of AIA with aniline and the introduction of carbon nanotubes show a synergistic enhancement of conductivity.     

Kinetics and thermodynamic study of aniline adsorption by multi-walled carbon nanotubes from aqueous solution

Multi-walled carbon nanotubes (MWCNTs) were used in the adsorptive removal of aniline, an organic pollutant, from an aqueous solution. It was found that carbon nanotubes with a higher specific surface area adsorbed and removed more aniline from an aqueous solution. The adsorption was dependent on factors, such as MWCNTs dosage, contact time, aniline concentration, solution pH and temperature. The adsorption study was analyzed kinetically, and the results revealed that the adsorption followed pseudo-second order kinetics with good correlation coefficients. In addition, it was found that the adsorption of aniline occurred in two consecutive steps, including the slow intra-particle diffusion of aniline molecules through the nanotubes. Various thermodynamic parameters, including the Gibbs free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°), were calculated. The results indicated that the spontaneity of the adsorption, exothermic nature of the adsorption and the decrease in the randomness reported as ΔG°, ΔH° and ΔS°, respectively, were all negative.     

Synthesis of reusable macroporous St/BMA copolymer resin and its absorbency to organic solvent and oil

In this paper, a reusable macroporous high oil absorption resin for oil spills was synthesized successfully by suspension copolymerization with styrene and butyl methacrylate as monomers. In the process of suspension copolymerization, a porogenic agent was introduced into the reaction system. Structure and surface morphology of the macroporous resin were characterized by Fourier transform infrared spectrometry, X‐ray photoelectron spectroscopy, and scanning electron microscopy. In addition, effects of different reaction factors on density and particle size of macroporous resins and effects of various factors on the oil absorbency of macroporous resins were discussed. Furthermore, oil absorption kinetics and repeatability of resin and the absorbency of the macroporous resin in various oils were also studied. Compared with the resin without macroporous structure, the maximum oil absorbency of the macroporous resin to the carbon tetrachloride (CCl₄) was 28.28 g/g, which increased by 61.42%. Meanwhile, the saturated oil absorption time of resin also decreased significantly from 7.5 to 2 hr. The macroporous high oil absorption resin presents predominant performance of reuse and regeneration. Moreover, the macroporous resin had certain absorbency (8.7 g/g) to crude oil, which makes it useful for marine oil spill. Copyright © 2015 John Wiley & Sons, Ltd.     

Validation of a real-time monitoring method for aniline in freshwater by high-performance liquid chromatography on porous graphitic carbon/electrospray ionization tandem mass spectrometry

Aniline is an anthropogenic organic compound widely used in polymer, rubber, pharmaceutical and dye industries but also used in biodegradability assays of chemical compounds as a positive biodegradation standard. By the two approaches, the rapid determination of aniline is necessary because of the high toxicity of aniline on hemoglobin. A high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) method for the determination of aniline in water is described here. This method, using benzylamine as internal standard, was validated. No time-consuming sample preparation was needed. A rapid separation (7 min between two chromatographic runs) of aniline and benzylamine was performed on a Hypercarb porous graphitic carbon column using a gradient of methanol and 100 mM formic acid. The obtained limits of detection and quantification were 10 and 1 ng/mL, respectively. The response for aniline was quadratic. We show that this problem could be circumvented by showing that the [calculated concentration = f(introduced concentration)] function was linear. The linearity range was 10-1000 ng/mL. An example of an application consisting of an aniline 42-day degradation kinetic in water was demonstrated.     

Influence of substrate stiffness on cell-substrate interfacial adhesion and spreading: a mechano-chemical coupling model

Highly ordered three dimensionally macroporous carbon spheres (3DMPCS) were successfully prepared against removable colloidal silica crystal bead templates by carbonization of glucose. The unique structural characteristics of the well-developed three dimensionally interconnected macropores were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption. The 3DMPCS have uniform large pore structures with size about 250 nm. Pt nanoparticles were supported on the macroporous carbon spheres by two aqueous impregnation methods, and it was found that the 3DMPCS supported Pt exhibited high electrocatalytic activity for methanol oxidation.     

中分子毒素在碳纳米管上的吸附

研究了两种不同形态的碳纳米管(随机生长多壁碳纳米管(MWCNTs)及定向生长多壁碳纳米管(ACNTs))对典型中分子毒素的吸附性能. 并与两种现有商用血液灌流吸附材料(活性炭(AC)及大孔吸附树脂(MR))进行了对比. 结果显示, 碳纳米管(CNTs)具有优异的中分子吸附能力, 其中MWCNTs对典型中分子毒素的吸附量可达47.18 mg·g-1, 为活性炭的10.8倍, 为大孔吸附树脂的5.5倍. 此外, 碳纳米管的吸附非常迅速, 中分子毒素在MWCNTs及ACNTs达到吸附平衡的时间仅为10 min和15 min, 而活性炭及大孔吸附树脂则分别需要60 min及120 min. 碳纳米管优异的吸附性能得益于其独特的微观结构所形成的发达的中孔. 因此, 碳纳米管可望成为高效的吸附材料, 应用于血液灌流中.     

Electrochemical oxidation of aniline in a silica sol–gel matrix

Electrochemical oxidation of aniline encapsulated in a silica solid electrolyte prepared by a sol–gel process yielded products that were dependent on the pore size. An acid-catalyzed process that used tetramethyl orthosilicate as the precursor and aniline as a dopant yielded the silica. When the aging time was limited to one day so that a mesoporous solid was obtained, the potentiodynamic oxidation of aniline at a carbon fiber electrode resulted in the formation of polyaniline. With aging times of 3–5 days, microporous silica was obtained. In this electrolyte, the formation of dimers and other oligomers was observed by cyclic voltammetry. Evidence for these products was the presence of a quasi-reversible redox couple at 0.2 V vs Ag/AgCl that was previously related to oligomeric aniline by Raman spectroscopy. The results supported the hypothesis that the pore structure of sol–gel electrolytes can influence the pathways of electrode reactions therein.     

Polyaniline‐Based Sensor Material for Potentiometric Determination of Ascorbic Acid

Polyaniline (PANI)‐based sensor material for determination of ascorbic acid was synthesized by oxidative chemical polymerization of aniline on a screen‐printed carbon‐paste electrode. The influence of PANI chemical structure formed under various polymerization conditions on the sensor response was investigated. The presence of aniline dimer derivatives in PANI structure was found to induce significant improvement of the limit of detection and the linear dynamic range without a change in sensitivity. The sensor prepared by aniline polymerization in pH 7 buffer leading to the product containing mainly the aniline dimer‐based units showed the best detection limit of 0.1 µM. It was shown that the PANI‐based sensor could be used for ascorbic acid analysis in the presence of citrate and lactate as interfering ions. A quantitative determination of ascorbic acid concentration in beverages and vitamins was performed.     

Synthesis of porous carbon balls from spherical colloidal crystal templates

Spherical inverse opal (IO) porous carbon was produced utilizing silica colloidal crystal spheres as templates. The spherical colloidal crystals were obtained through the self-assembly of monodisperse particles inside an emulsion droplet with confined geometry. The templates were inverted using a carbon precursor, phenol-formaldehyde (PF) resol. We demonstrated a two-step synthesis involving the subsequent infiltration of the PF resol precursor into the spherical colloidal crystal template and a one-step synthesis using a silica colloidal solution containing dissolved PF resol. In the former case, the sizes of the IO carbon balls were controlled by the size of the colloidal crystal templates, and diameters of a few micrometers up to 50 μm were obtained. The average diameter of the macropores created by the silica particles was 230 nm. Moreover, meso-/macroporous IO carbon balls were created using block-copolymer templates in the PF resol. In the one-step synthesis, the concentration of PF resol in the colloidal solution controlled the diameter of the IO carbon balls. IO balls smaller than 3 μm were obtained from the direct addition of 5% PF resol. The one-step synthesis produced rather irregular porous structures reflecting the less ordered crystallization processes inside the spherical colloidal crystals. Nitrogen adsorption and cyclic voltammetry measurements were conducted to measure the specific area and electroactive surface area of the IO carbon balls. The specific area of the mesopores-incorporated IO carbon balls was 1.3 times higher than that of bare IO carbon balls. Accordingly, the meso-/macroporous porous carbon balls exhibited higher electrocatalytic properties than the macroporous carbon balls.     

Reduction of nitrobenzene to aniline with carbon monoxide and water

Modified catalytic system composed of selenium and cocatalysts such as pyridine and aniline, applied in the reduction of nitrobenzene to aniline in the presence of carbon monoxide and water is described. The reaction proceeds at 150–200°C and 3–4 MPa gauge pressure. After 1–2 h the reaction is complete, reaching nitrobenzene conversions of up to 98% with selectivity to aniline near 100%.     

Template synthesis of ordered macroporous hydroxyapatite bioceramics

Hydroxyapatite has found wide application in bone tissue engineering. Here we use a macroporous carbon template to generate highly ordered macroporous hydroxyapatite bioceramics composed of close-packed hollow spherical pores with interconnected channels. The template has advantages for the preparation of ordered materials.     

Facile preparation of hierarchically porous carbon using diatomite as both template and catalyst and methylene blue adsorption of carbon products

Hierarchically porous carbons were prepared using a facile preparation method in which diatomite was utilized as both template and catalyst. The porous structures of the carbon products and their formation mechanisms were investigated. The macroporosity and microporosity of the diatomite-templated carbons were derived from replication of diatom shell and structure-reconfiguration of the carbon film, respectively. The macroporosity of carbons was strongly dependent on the original morphology of the diatomite template. The macroporous structure composed of carbon plates connected by the pillar- and tube-like macropores resulted from the replication of the central and edge pores of the diatom shells with disk-shaped morphology, respectively. And another macroporous carbon tubes were also replicated from canoe-shaped diatom shells. The acidity of diatomite dramatically affected the porosity of the carbons, more acid sites of diatomite template resulted in higher surface area and pore volume of the carbon products. The diatomite-templated carbons exhibited higher adsorption capacity for methylene blue than the commercial activated carbon (CAC), although the specific surface area was much smaller than that of CAC, due to the hierarchical porosity of diatomite-templated carbons. And the carbons were readily reclaimed and regenerated.