可见光辐射下富勒烯[60]–氧化铁复合催化剂的制备及光芬顿法降解有机污染物研究（英文）

采用简单的可升级的化学浸渍法,将Fe_2O_3掺杂到富勒烯[60](C_(60))上,制得C_(60)-Fe_2O_3纳米复合材料.采用了粉末X射线衍射、X射线光电子能谱(XPS)、扫描电镜、高分辨透射电镜、紫外-可见吸收光谱、拉曼光谱和傅里叶变换红外光谱,对其进行了表征.结果发现,XPS数据中,Fe2p_(3/2)和Fe2p_(1/2)的XPS特征峰分别位于结合能710.9和724.1 eV处,对应Fe_2O_3的Fe~(3+).富勒烯颗粒均匀分散在Fe_2O_3纳米颗粒表面,Fe_2O_3纳米颗粒的平均尺寸大约为20–30 nm;Fe_2O_3对于可见光只有微弱的吸收,而制备出的C_(60)-Fe_2O_3纳米复合材料对于可见光有较强的吸收响应.本文将C_(60)-Fe_2O_3纳米复合光催化材料用于光催化降解50 mL,20mg/l MB和50 mL,10 mg/L苯酚实验.结果发现,在双氧水存在下和可见光(420 nm)辐射条件下,C_(60)-Fe_2O_3对上述有机污染物均有较好的降解效果.通过测定上述有机物的削减程度,评估了C_(60)-Fe_2O_3催化剂的光催化活性,通过改变实验条件,得到可见光/C_(60)-Fe_2O_3/双氧水体系的最佳光催化降解条件:在pH值为3.06~10.34的范围内,投加0.02 g催化剂,5 mol/L双氧水.结果表明,在最佳条件下,亚甲基蓝在80min内脱色率能达到98.9%,矿化率能达到71%.浸出实验的结果表明,C_(60)-Fe_2O_3复合光催化剂中的铁浸出量可以忽略不计.经过5次循环使用后,C_(60)-Fe_2O_3复合光催化剂仍具有较高的光催化活性.为了进一步验证C_(60)-Fe_2O_3复合光催化剂的应用广泛性,本文在可见光/C_(60)-Fe_2O_3/双氧水体系下,开展了降解RhB,MO和苯酚的试验,结果发现,该催化剂它们也具有高的降解效果.机理研究发现,C_(60)-Fe_2O_3复合光催化剂的高效催化能力可归因于C_(60)和Fe_2O_3的协同效应:在可见光辐射下,由于C_(60)具有独特的光敏性特征,能够接收电子并把它们转移到Fe_2O_3的Fe3d轨道,并通过一系列反应,达到Fe~(3+)/Fe~(2+)循环平衡.利用活性组分捕集实验,对光催化反应过程中的主要活性氧化剂进行了区分.结果表明,羟基自由基在整个过程中发挥了最主要的作用.     

Microwave-hydrothermal synthesis and photocatalytic properties of biomass charcoal/TiO2 nanocomposites

Biomass charcoal-doped titanium dioxide (C/TiO₂) composites were proposed by microwave-hydrothermal and calcination method using tetrabutyl titanate as the titanium source and lignin as the carbon source. TiO₂ crystals with different morphologies could be successfully adsorbed onto the surface of biomass charcoal. These products were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), derivative thermogravimetric (DTG), UV–vis diffuser flection spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR), and Brunauer–Emmett–Teller (BET). The photocatalytic activities of the as-obtained composites were checked under visible light irradiation. The results showed that both the microwave-hydrothermal temperature and time played an important role in the microstructure and photocatalytic activity of the samples. The rapid microwave-hydrothermal with the thermal post-treatment provides a promising route for the fabrication of biomass charcoal-doped nanocomposites materials.     

Characterization of a Stable Adaptive Calibration Model Using Near-Infrared Spectroscopy and Partial Least Squares with a Kalman Filter

The calibration model of near-infrared (NIR) spectra established using the Kalman filter-partial least square (partial least squares combined with a Kalman filter) method can be adapted to outdated equipment, environmental changes, external samples, and other applications. However, the variance of the measurement noise estimation for NIR spectrum measurements cannot be easily obtained using Kalman filter-partial least squares; therefore, the variance in the measurement noise is often assumed to be zero for the Kalman filter-partial least square calibration model, which affects the stability of the model. In this study, the measured input and output data were used effectively, and the gamma test method for estimating the measurement noise variance was used to improve the stability of the Kalman filter-partial least square calibration model. First, an accurate estimation of the measurement noise variance was obtained, and accurate modeling was then performed using Kalman filter-partial least squares. Finally, 600 abandoned drilling fluid samples were used to confirm the validity of the proposed method. The Kalman filter-partial least square and gamma test-Kalman filter-partial least square methods are compared. Testing of external samples 401–600 demonstrated that the stability of the Kalman filter-partial least square model decreased. The root mean square error of the prediction of the Kalman filter-partial least square model was 27.135, which was worse than that of the gamma test-Kalman filter-partial least square model (20.307). The validation results show that the proposed method has better stability in tracking the evolution of the NIR spectrometer’s measurement state.     

锂硫电池正极用硫/介孔碳复合材料的制备及电化学性能

制备了以十二烷基硫酸钠(SDS)为模板的介孔碳,并将介孔碳和单质硫采用熔融渗透法复合制得硫/介孔碳复合材料。SEM、TEM和BET结果显示介孔碳成直径约为500 nm的大小均一的球体,存在孔径为2 nm的微孔;单质硫充分填充在介孔碳的微孔中。以硫/介孔碳复合物作为锂硫电池正极材料时显示出高的电化学性能。初始放电容量高达1519 mAh·g^-1,在200 mA·g^-1的电流密度下充放电200个循环后依然能保持在835 mAh·g^-1。硫/介孔碳复合材料的高倍率性能和优异的循环稳定性,源于介孔碳良好的导电性及其孔结构的固硫作用。     

Chiral separation abilities of homogeneously synthesized cellulose 3,5-dimethylphenylcarbamates: Influences of degree of substitution and molecular weight

A series of cellulose 3,5-dimethylphenylcarbamates(CDMPCs) with different degrees of substitution(DS) and degrees of polymerization(DP) were homogeneously synthesized in 1-allyl-3-methylimidazolium chloride(Amim Cl). Then, the CDMPCs were coated on silica gel and used as chiral stationary phases(CSPs), and their chiral recognition abilities for seven racemates were evaluated by high performance liquid chromatography. The results showed that DS and DP of CDMPCs had a great influence on chiral recognition abilities of the CSPs. The CSPs with the DS ≈ 1 gives a low chiral recognition to most racemates. On the contrast, the CSPs with the DS ? 2 exhibited high chiral separation abilities. For example, six racemates could be separated on the CSP with CDMPC of DS ≈ 2(CSP-2). Especially, for the enantioseparation of 1-(2-naphthyl) ethanol and Tr?ger's base, CSP-2 gave the highest separation ability in all of CSPs. On the other hand, when the DP of cellulose was in a range from 39 to 220, the chiral separation abilities of CDMPCs increased as the DP increased. This work demonstrates that the structure of cellulose esters such as DS and DP has important effect on their chiral separation ability, and therefore provides a practical method to design and prepare desirable CSPs for different racemates.     

Ultrathin Alternating Copolymer Nanotubes with Readily Tunable Surface Functionalities

Well‐defined ultrathin nanotubes (30 nm in diameter and of micrometer‐scale length) were generated through the self‐assembly of a novel alternative copolymer synthesized using an epoxy–thiol click‐chemistry reaction. The self‐assembly mechanism was investigated both by experiments and using dissipative particle dynamics (DPD) simulations. The obtained nanotubes can be readily functionalized with carboxy groups, amino groups, peptides, or other groups by simple modular click copolymerization.     

Precise Macroscopic Supramolecular Assembly by Combining Spontaneous Locomotion Driven by the Marangoni Effect and Molecular Recognition

Macroscopic supramolecular assembly bridges fundamental research on molecular recognition and the potential applications as bulk supramolecular materials. However, challenges remain to realize stable precise assembly, which is significant for further functions. To handle this issue, the Marangoni effect is applied to achieve spontaneous locomotion of macroscopic building blocks to reach interactive distance, thus contributing to formation of ordered structures. By increasing the density of the building blocks, the driving force for assembly transforms from a hydrophobic–hydrophobic interaction to hydrophilic–hydrophilic interaction, which is favorable for introducing hydrophilic coatings with supramolecular interactive groups on matched surfaces, consequently realizing the fabrication of stable precise macroscopic supramolecular assemblies.     

质子交换膜燃料电池梯度化膜电极

为实现质子交换膜燃料电池的高性能(高功率密度或大电流密度)、低成本(低铂载量)、长寿命发电,人们尝试在燃料电池的核心部件膜电极结构中引入梯度化设计的概念。梯度化膜电极包括膜电极中各组件的梯度化:气体扩散层的PTFE含量与孔隙率的梯度化,催化层的催化剂与Nafion用量的梯度化以及微孔层的疏水性与孔隙率的梯度化。梯度化膜电极中催化剂分布、孔隙率分布、亲/疏水性分布合理,具有良好的三相反应界面以及质子、电子、反应气体、水等多相物质高效传输通道,从而能满足在低铂载量、低加湿以及高电流密度条件下高性能稳定工作。本文整理了近几年来有关燃料电池梯度化膜电极研究的相关文献,梳理了梯度化膜电极研究发展脉络,归纳总结了各种梯度化膜电极的制备方法、性能以及构效关系,并展望了梯度化膜电极下一步研究方向,对高性能、低成本、长寿命的燃料电池开发具有指导意义。     

沸石分子筛材料在消除挥发性有机化合物反应中的吸附与催化性能

作为空气污染物的主要成分之一,挥发性有机化合物(VOCs)会极大地破坏生态环境并损害人体健康。在众多消除 VOCs的方法中,吸附法由于操作简单、成本低廉的优势而在工业上得以广泛应用。催化燃烧法则因去除效率高,适用范围广且无二次污染等优点被认为是 VOCs消除最有效的手段之一。
　　目前,活性炭是最常用的 VOCs吸附剂,但存在再生困难、抗湿性差、易燃等诸多问题。与活性炭等常规吸附剂相比,沸石分子筛作为 VOCs吸附剂其主要优势在于：(1)沸石分子筛的疏水性可调,通过调控分子筛骨架的硅铝比可以调节分子筛的亲疏水性,高硅铝比的沸石分子筛有着优异的疏水性能,从而可以有效降低在一定湿度条件下水对 VOCs分子的竞争吸附;(2)均一的孔径分布可以有效地进行分子识别,从而使吸附剂对VOCs的选择性吸附性大大提高;(3)沸石分子筛一般由硅铝构成,本身不可燃且水热稳定性好,因此能够与微波加热等其他手段相结合以降低吸附剂重生能耗,提高操作安全性;(4)沸石分子筛比表面积大,吸附容量高,是作为蜂窝转轮吸附技术中吸附剂的理想材料,而该技术是目前工业大规模消除VOCs的研究热点。因此,沸石分子筛由于其独特的性质,被视为一种简单高效、选择性好的VOCs吸附剂。现阶段,催化燃烧VOCs所使用的催化剂常用金属氧化物作为载体,但是金属氧化物比表面积相对较小且孔道结构不均一,因此严重影响了催化剂对VOCs的催化燃烧效率,限制了催化燃烧活性的提高。而与金属氧化物载体相比,沸石分子筛材料具有均一的孔道结构以及相对较大的比表面积等优点,而将具有较好吸附选择性和吸附容量的沸石分子筛作为载体,负载活性组分后可以实现催化剂催化燃烧性能的显著提高,从而成为VOCs催化燃烧的理想催化剂。
　　本文综述了目前沸石分子筛材料作为吸附剂和催化剂载体的负载型催化剂消除各类VOCs的研究进展。对于沸石分子筛作为VOCs吸附剂,我们小结了影响其吸附容量和吸附选择性的因素,发现分子筛的孔道大小和阳离子类型与VOCs的吸附情况密切相关。在此基础上,进一步简单介绍了分子筛蜂窝吸附转轮技术的研究现状。对于沸石分子筛作为催化剂载体,我们总结了其用于各类VOCs催化燃烧的研究情况,如烷烃类、芳烃类和醛类等。探究了催化性能的影响因素及相应的催化机理,发现分子筛的孔道结构、阳离子类型、硅铝比等都会显著影响沸石分子筛负载型催化剂的催化活性。最后,探讨了沸石分子筛应用于VOCs消除目前所存在的问题,同时展望了该领域未来的研究和发展方向。     

Temperature and pH Dually-responsive Poly(β-amino ester) Nanoparticles for Drug Delivery

Stimuli-responsive polymers have undoubtedly been of great interest in the past decades due to a variety of their potential applications in biomedical territory. However, their non-degradability limits their in vivo applications. Herein, we report a novel pH and temperature dual-stimuli responsive-poly(β-amino ester). The pH/temperature sensitivities are interrelated and can be easily tuned by changing PEG-diacrylate chain length and the percentage of biamines in the feed ratio. These dual-responsive polymers are very useful in drug delivery. Reaction of methyl ether poly(ethylene glycol)(MPEG) and poly(β-amino ester) resulted in an amphiphilic MPEG-PBAE block copolymer which could form nanoparticles by selfassembly. A hydrophobic drug(DOX) was loaded in the self-assembled nanoparticles at low temperature without using organic solvents. The loaded drug was released very slowly and steadily at 37 ℃ under physiological conditions(p H 7.4), but rapidly released from the micelles in weakly acidic environments(pH 6.4 and 5.0) for intracellular drug release. Thus, these poly(β-amino ester) polymers constitute ideal drug carriers since their thermal sensitivity allows the drug loadings without using organic solvent and their pH sensitivity permits fast intracellular drug release.