低阶煤中含氧官能团分布的研究

采用化学法测定了四种典型中国低阶煤中羧基、醇羟基、酚羟基、甲氧基和羰基含氧官能团。其中,羧基的定量分析采用醋酸钙溶液和pH值为8.3的缓冲溶液进行,分析了测定条件对羧基和酸性含氧官能团测定结果的影响。结果表明,在N₂气氛下比空气条件下测定羧基含量准确,褐煤中羧酸根的主要存在形式为羧酸盐,酸洗后煤样中酚羟基的测定值随着离子交换溶液pH值的增加而增大;褐煤中的含氧官能团主要是羧基和羟基,分别占总氧量的34.49%和34.79%;在不同低阶煤中存在不同含量的羰基,甲氧基含量较小。     

低温加压热解脱氧对胜利褐煤亲水性的影响

在固定床反应器中考察了低温（200~350 ℃）、加压（0.25~8.00 MPa）热解条件下胜利褐煤主要含氧官能团的变化规律,并进一步分析了褐煤中含氧官能团的脱除对其吸水能力的影响。结果表明,温度升高对胜利褐煤中羧基和酚羟基的脱除非常有效,压力变化对羧基脱除影响极小,而在3.00~4.00 MPa时对酚羟基脱除效果最佳;同时羧基对煤样的表面极性和亲水性具有决定性作用,当羧基含量不变时,固体比表面积对煤样的吸水性影响相对较明显。     

羟基自由基对多壁碳纳米管表面和结构的影响

碳纳米管纯化后，使用Fenton试剂产生羟基自由基对碳管进行改性处理，研究羟基自由基对碳管表面和结构的影响，并与碳管的混酸处理结果进行比较。FTIR结果表明：经Fenton试剂化学处理后，碳管表面主要引入羟基和羰基，而混酸能“剪切”碳管，产生大量羧基和羰基等官能团。根据Fenton试剂产生羟基自由基的机理，分析了Fenton试剂处理条件的影响因素，控制反应条件即过氧化氢与亚铁离子物质的量之比保持在10左右，而pH值则维持在3左右，对碳管进行改性处理。依据碳管Fenton试剂处理前后的FTIR谱图变化，初步探讨了羟基自由基与多壁碳纳米管作用的可能机理。机理分析表明，改性后碳管表面的羟基和羰基是羟基自由基对碳管上的不饱和键进行加成氧化的结果。     

乙炔法合成醋酸乙烯催化剂载体表面羧基与羰基作用机理的研究

比较了硝酸、硫酸、过氧乙酸改性对载体比表面积、孔结构、pH值以及载体表面基团的影响. 研究了过氧乙酸(PAA)改性条件对催化剂活性的影响. 改性提高了活性炭表面羧基和羰基的含量, 由在最佳PAA改性条件下制备的乙炔法合成醋酸乙烯催化剂生产能力比未经过氧乙酸改性活性炭制备的催化剂提高了14.58%. 得到了过氧乙酸改性后活性炭表面羧基和羰基总量(m)和合成醋酸乙烯催化剂生产能力(P)之间的关系为P＝1.83＋2.26×10－3×e3.17m, 并讨论了催化剂表面羧基与羰基提高催化剂活性的机理.     

PTFE超细颗粒的表面活化与化学接枝

采用钠萘络合物化学腐蚀液对聚四氟乙烯(PTFE)超细颗粒表面进行活化, 对活化后的表面用氨基十一酸碳链进行化学接枝, 并用IR和XPS技术对活化及接枝前后颗粒的表面结构和价键状态进行了表征. 结果表明：活化后的PTFE超细颗粒表面上存在羟基、羰基、羧基等活性官能团, 并出现炭化现象；氨基十一酸的氨基能与表面羟基发生缩合反应, 并接枝于PTFE超细颗粒表面.     

改性吐温-20的合成及其乳化性能

利用羟基硅油的羟基与丁二酸酐反应,合成带有羧基的改性羟基硅油,其羧基与吐温-20分子中的羟基发生酯化反应,合成了含改性羟基硅油的改性吐温-20。乳化实验结果表明,羟基硅油改性吐温-20比吐温-20具有更好的乳化效果,离心分离稳定性更好。     

煤中含氧官能团的分析方法介绍

煤中氧的存在形式和含氧量是研究煤物理结构和化学性能的基础。本文对煤中含氧官能团的各类分析方法进行了总结,介绍了确定煤中羟基(醇羟基和酚羟基)、羧基、羰基、醚键等含氧官能团的化学及物理定性与定量方法。并对这些方法的易操作性、准确性等进行了比较,旨在从分析测试机理和煤结构组成出发,了解煤中含氧官能团和相关煤结构的分析进展。     

内蒙胜利褐煤腐殖酸对煤平衡复吸水的影响

研究了褐煤中重要的成分腐殖酸对褐煤水分的影响。测定了内蒙胜利褐煤中腐殖酸含氧官能团的含量,并分析了褐煤、棕黑腐殖酸和残余煤的等温吸附和脱附曲线。通过Dent吸附等温模型研究了褐煤和棕黑腐殖酸第一层吸附和第二层吸附。结果表明,胜利褐煤2/5羧基和1/5羟基是由腐殖酸提供的。棕黑腐殖酸相对褐煤孔径和孔容较小,不利于水簇的形成。腐殖酸对褐煤的复吸水是不利的     

有机硅试剂在药物合成中的应用

主要介绍了有机硅试剂作为保护剂对药物结构中含有羟基、羧基、不饱和键、氨基、羰基和其它官能团的保护及应用情况,以及在合成中间体烯醇硅醚等方面的应用.     

硝酸改性活性炭上氧/氮官能团对脱汞性能的促进作用

采用硝酸氧化手段对活性炭进行了表面处理, 并在固定床反应器上测试了其脱除单质汞的性能. 研究表明, 在模拟烟气中硝酸改性活性炭能有效脱除单质汞. 采用元素分析、Brunauer-Emmett-Teller (BET)比表面积、扫描电子显微镜(SEM)、拉曼(Raman)光谱、Boehm滴定、程序升温脱附(TPD)和X射线光电子能谱(XPS)等手段研究了活性炭表面官能团对其脱汞性能的影响. 结果表明: 硝酸氧化处理能同时增加活性炭表面含氧官能团和含氮官能团的含量. 与改性活性炭的物理性质相比, 其化学性质对脱汞性能的影响更大, 单质汞主要被改性活性炭氧化为HgO而去除. 在脱汞反应中, 羰基、酯基和酸酐等含氧官能团可能是活性吸附位点, 反应后这些官能团被还原为羟基或者醚基; 而吡咯等含氮官能团可能是活性催化位点. 此外, 基于上述表征结果提出了硝酸改性活性炭表面官能团的脱汞机制.     

Study on the structure and reactivity of COREX coal

COREX is the primary process in the current smelting reduction method. The process has strict coal quality standards. Combustion processes of coal used in the COREX operating system were analyzed using a synchronous thermogravimetric analyzer combined with a mass spectrometer. The microcosmic structure and macerals were observed by an electronic scanning microscope. The qualitative and quantitative determinations of oxygen functional groups, such as phenolic hydroxyl, carboxyl, carbonyl, and methoxy groups were detected by the Fourier Transform Infrared spectrometer (FT-IR) and through chemical analysis methods. In addition, the evolution of the chemical structure and transformation mechanism of organic oxygen functional groups during COREX coal combustion have been thoroughly investigated. This study proposes a new coal-requirement index system and coal blending method, which will increase the expansion of coal selection and decrease the overall usage of coal during COREX.     

Molecular dynamics modeling of the interface between surface functionalized graphitic structures and calcium-silicate-hydrate: interaction energies, structure, and dynamics

Molecular dynamics simulations were performed to study the molecular-scale energetic, structural, and dynamic properties of the interface between surface functionalized graphitic structures and calcium-silicate-hydrate (C-S-H). The 9 A tobermorite structure was used as a model for C-S-H, the main building block ("the glue") that hold a cementitious matrix together. Six types of carbon surface structures were investigated: a pristine graphite plane and five graphite planes functionalized with hydroxyl (OH), carboxyl (COOH), carboxylate (COO(-), deprotonated carboxyl), carbonyl (CO), and amine (NH(2)) groups. Results demonstrated the dominant role of electrostatic forces in the interfacial interactions and indicated that the polarity of the functional group can be used as an indicator of affinity to C-S-H. MD simulations revealed that an optimal number of polar oxygen containing groups may exist for efficient graphitic structure/cement interaction and emphasized the mediating role of Ca(2+) counterions in the interfacial interactions.     

Rational Design of Carboxyl Groups Perpendicularly Attached to a Graphene Sheet: A Platform for Enhanced Biosensing Applications

Graphene oxide (GO)‐based materials offer great potential for biofunctionalization with applications ranging from biosensing to drug delivery. Such biofunctionalization utilizes specific functional groups, typically a carboxyl moiety, as anchoring points for biomolecule. However, due to the fact that the exact chemical structure of GO is still largely unknown and poorly defined (it was postulated to consist of various oxygen‐containing groups, such as epoxy, hydroxyl, carboxyl, carbonyl, and peroxy in varying ratios), it is challenging to fabricate highly biofunctionalized GO surfaces. The predominant anchoring sites (i.e., carboxyl groups) are mainly present as terminal groups on the edges of GO sheets and thus account for only a fraction of the oxygen‐containing groups on GO. Herein, we suggest a direct solution to the long‐standing problem of limited abundance of carboxyl groups on GO; GO was first reduced to graphene and consequently modified with only carboxyl groups grafted perpendicularly to its surface by a rational synthesis using free‐radical addition of isobutyronitrile with subsequent hydrolysis. Such grafted graphene oxide can contain a high amount of carboxyl groups for consequent biofunctionalization, at which the extent of grafting is limited only by the number of carbon atoms in the graphene plane; in contrast, the abundance of carboxyl groups on “classical” GO is limited by the amount of terminal carbon atoms. Such a graphene platform embedded with perpendicularly grafted carboxyl groups was characterized in detail by X‐ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy, and its application was exemplified with single‐nucleotide polymorphism detection. It was found that the removal of oxygen functionalities after the chemical reduction enhanced the electron‐transfer rate of the graphene. More importantly, the introduction of carboxyl groups promoted a more efficient immobilization of DNA probes on the electrode surface and improved the performance of graphene as a biosensor in comparison to GO. The proposed material can be used as a universal platform for biomolecule immobilization to facilitate rapid and sensitive detection of DNA or proteins for point‐of‐care investigations. Such reactive carboxyl groups grafted perpendicularly on GO holds promise for a highly efficient tailored biofunctionalization for applications in biosensing or drug delivery.     

利用X射线光电子能谱研究马家塔煤显微组分中氧的赋存形态

煤中氧的赋存形态是煤结构研究的重要内容，煤炭加工转化（如煤的热解、直接加氢液化等）也需要确实详尽的煤中氧赋存形态的数据信息。x射线光电子能谱法（x—ray Photoelectron Speetroscopy，XPS）是近年来新出现的最有效的元素分析方法之一，目前，已在化学、物理、生物等各个领域中得到广泛应用。1974年，XPS分析方法首次用于煤的研究，近年来，XPS成为研究煤中硫和氮存在形态的有效方法之一。许多学者在煤中无机矿物中碳、氧、硫的存在形态及XPS直接测定煤中有机硫等方面做过较多研究工作，但由于煤结构的复杂性、实验条件不尽相同以及煤中矿物的干扰等，以往的研究结果并不完全相同。     

东胜长焰煤热解含氧官能团结构演化的13C-NMR和FT-IR分析

以东胜煤田色拉一号井田2号煤层长焰煤为研究对象,利用浮沉离心法富集其镜质组。基于工业分析、元素分析、¹³C-NMR、FT-IR、谱图分峰拟合技术和化学分析测试,求取镜煤及一系列热解煤含氧官能团结构与含量参数,从不同角度研究了含氧官能团的分布规律与演化特点。镜煤中羧基、羰基含量分别为8.91~10.90 mol/kg、1.61~1.79 mol/kg,随热解温度升高羧基显著减少。热解作用促使以端基形式连接在脂肪链或脂肪环结构氧上的甲基和亚甲基首先脱去,且在温度高于350 ℃后基本稳定。氧在热解过程赋存状态的变化是芳香体系与脂肪体系相互竞争的结果,510 ℃热解煤中芳香类氧和脂肪类氧的含量分别为7.49、3.45 mol/kg。羟基的演化过程与热解过程中氧的赋存状态密切相关。随着热解过程的进行,在热解温度低于440 ℃时,各种羟基含量均减少,热解过程对于大分子网络的破坏干扰了各种氢键作用,而羟基π作用则暂时增强,至510 ℃时各种氢键含量均降为最低。东胜长焰煤中含氧官能团化学活性顺序为:[COOH]>[R-O]>[Ar-O-Ar,Ar-O-C,C-O-C]>[C=O]。镜煤非活性醚键含量为0.68 mol/kg,活性醚键为0.48 mol/kg,主要为非活性醚键。     

Surface and electrochemical properties of polypropylene track membrane modified by plasma of non-polymerizing gases

The surface and electrochemical properties of polypropylene track membrane treated by plasma of nitrogen, air, and oxygen are studied. The effect of the plasma-forming gas composition on the surface morphology is considered. The membrane surface microrelief formed during the gas-discharge etching is found to change. Moreover, the non-polymerizing gas plasma treatment induces oxidation of the membrane surface layer and generates oxygen-containing functional groups, mostly carbonyl and carboxyl. The higher membrane roughness and its hydrophilization is shown to lead to its better wettability. In addition, the presence of polar groups in the membrane surface layer modifies its hydrodynamic and electrochemical properties so that water permeability and conductivity of modified membranes increase.     

Influence of atmospheric plasma on physicochemical properties of vapor-grown graphite nanofibers

Vapor-grown graphite nanofibers (GNFs) were modified by plasma treatments using low-pressure plasmas with different gases (Ar gas only and/or Ar/O2 gases), flow rates, pressures, and powers. Surface characterizations and morphologies of the GNFs after plasma treatment were investigated by X-ray photoelectron spectroscopy (XPS), contact angle, titration, and transmission electron microscopy (TEM) measurements. Also, the investigation of thermomechanical behavior and impact strengths of the GNFs/epoxy composites was performed by dynamic-mechanical thermal analysis (DMTA) and Izod impact testing, respectively. The plasma treatment of the fibers changed the surface morphologies by forming a layer with a thickness on the order of 1 nm, mainly consisting of oxygen functional groups such as hydroxyl, carbonyl, and carboxyl groups. After functionalization of the complete surfaces, further plasma treatment did not enhance the superficial oxygen content but slightly changed the portions of the functional groups. Also, the composites with plasma-treated GNFs showed an increase in T(g) and impact strength compared to the composites containing the same amount of plasma-untreated GNFs.     

Acid/Base-treated activated carbons: characterization of functional groups and metal adsorptive properties

Surface modification of activated carbons by various physicochemical methods directs an attractive approach for improvement of heavy metal uptake from aqueous solutions. Activated carbons were modified with HCl and HNO3 optionally followed by NaOH. The effects of surface modifications on the properties of the carbons were studied by the specific surface area, carbon pH, and total acidity capacity as well as by scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The modifications bring about substantial variation in the chemical properties whereas the physical properties remain nearly unchanged. NaOH causes an increase in the content of hydroxyl groups, while the HCl treatment results in an increase in the amount of single-bonded oxygen functional groups such as phenols, ethers, and lactones. The HNO3 modification generates a large number of surface functional groups such as carbonyl, carboxyl, and nitrate groups. The HNO3 modification significantly increases the copper adsorption, while the HCl treatment slightly reduces the copper uptake. Most of the copper ions are adsorbed rapidly in the first 2 h; the adsorption equilibrium is established in around 8 h. An intraparticle diffusion model successfully describes the kinetics of copper adsorption onto the carbons.     

神木煤显微组份的表面特性

煤表面亲水性是影响水煤浆(CWS)流变性能的重要因素。关于表面活性剂和煤岩组成对煤亲水性影响的研究比较少,本文在这方面进行了一些工作,旨在弄清神木煤配CWS的制约因素。1.实验部分煤样采自神府煤田神木区四门沟矿3~(-1)层。用手选法选出镜煤和丝炭,经破碎、筛分制成80—180目研究样品。