碳纳米管负载二氧化铈纳米粒子的研究

通过在液相沉淀反应中直接加入碳纳米管作为沉淀承载基体制备了碳纳米管负载的二氧化铈纳米颗粒。电镜分析证实了在碳管的表面高密度地均匀沉积了多层粒径为4～6nm的二氧化铈粒子,也有部分二氧化铈粒子填充进入碳管的内腔,形成了二氧化铈,多壁碳管复合材料,所获得的纳米复合材料可望成为一种新型的高效催化剂,在催化领域特别是车辆尾气处理上有潜在应用。     

加热对ZnS:Mn/聚乙烯吡咯烷酮纳米纤维的影响

通过静电纺丝的方法制备了具有发光特性的ZnS:Mn/聚乙烯吡咯烷酮纳米纤维,电纺溶液中的溶剂是DMF、水、乙醇,使用了扫描电子显微镜,荧光光谱仪,透射电子显微镜,X-射线衍射仪,研究了加热对电纺溶液中含有DMF溶剂的电纺纤维的影响,结果是纤维之间的分离程度提高,纤维内部的纳米粒子变得清晰,纤维内部粒子的结晶度提高,该纤...     

一种碳纳米管内沉积金属粒子催化剂及其制备和应用

<正>申请号:CN201910799065.X申请日:20190827公开(公告)号:CN110624582A本发明公开了一种碳纳米管内沉积金属粒子催化剂,该催化剂由碳纳米管、碳量子点和金属纳米粒子组成;所述的碳纳米管为开孔的单壁或多壁碳管,碳纳米管外壁负载有碳量子点,碳纳米管内壁镶嵌有金属纳米粒子。本发明所述的制备方法是先将碳量子点负载到碳纳米管外壁,再利用碳量子点的给电子特性诱导带负电的金属络合离子自发进     

Au/TiO_2纳米光催化剂的制备及光催化性能研究

采用水热法制备TiO_2纳米粒子,通过光化学还原沉积法制备了Au/TiO_2光催化剂,并利用SEM、XRD、EDS和DRS等技术对样品进行了表征,考察了不同Au含量对TiO_2纳米粒子光催化分解水制氢活性的影响。研究结果表明,通过此方法可以成功地将Au纳米粒子均匀地分散在TiO_2纳米粒子表面,用适量Au进行表面修饰不仅能提高TiO_2对可见光的吸收,还可以促进TiO_2光生电子-空穴对的分离效率,从而提高了TiO_2纳米粒子的光催化活性。其中,3%Au/TiO_2纳米粒子的光催化活性最高。     

SAS-A技术制备聚乙二醇微粒

超临界流体抗溶剂-雾化(SAS-A)技术研究用聚乙二醇(PEG6000)/乙醇/水体系制备聚乙二醇(PEG)微粒。探讨预膨胀压力、溶液浓度和溶液流量等工艺参数对微粒形貌及粒径的影响;重点探讨SAS-A技术中使用不同溶剂对颗粒形态和粒径分布的影响。结果表明,以丙酮和乙醇为溶剂的SAS-A技术可以制得形态基本上为球形的PEG微粒,粒径分布分别可以控制在1~5μm和2~15μm之间;增大预膨胀压力容易得到分散的球形微粒,并能减小微粒粒径,微粒粒径分布也随之变窄。对应PEG/丙酮体系,溶液浓度升高,所得到的微粒粒径增大;对应PEG/乙醇体系,溶液浓度对粒径大小影响不大,但溶液浓度增大会使粒径分布变宽。采用乙醇水溶液为溶剂时,初始乙醇浓度越低,移出水的效果越差,易形成结块的不规则微粒。     

基于双金属Mo-Fe催化剂调控碳纳米管阵列生长

化学气相沉积是制备碳纳米管阵列最常用的方法。催化剂作为碳纳米管生长的模板,通过改变催化剂粒子结构来调控阵列结构是生长碳纳米管阵列的一项重要手段。单金属Fe催化剂是碳管阵列生长最常用的催化剂,但单金属催化剂调控困难,而双金属催化剂具有组分可调、工艺简单、易放大等优势,在碳纳米管阵列结构调控方面展现出了潜在的优势。通过设计碳管生长的催化剂,在原先单金属Fe的基础上加入金属Mo并且改变金属Mo的比例可以有效地控制最终催化剂粒子的尺寸与直径分布,从而实现对阵列的堆积密度、取向性、碳管的壁数与质量等的调控。将催化剂粒子尺寸与直径分布的改变归结为金属Mo对Fe催化剂的"调控作用",这种"调控作用"很好地解释了碳纳米管的生长速率、内部结构与成核后的双金属Mo-Fe催化剂粒子的关联性。     

纳米碳管/PP复合材料的性能研究

本试验主要用溶液共混方法制备碳纳米管/聚丙烯复合材料,并测试不同碳纳米管含量对复合物的热稳定性能、结晶性能的影响。结论表明,随着碳纳米管含量的增加,复合材料的结晶熔点有所提高,复合材料的热稳定性能也逐渐提高。纳米碳管的含量对聚丙烯的结晶性能也有一定的影响,随着纳米碳管的加入,聚丙烯的结晶度逐渐提高,加入量超过2%时,结晶度开始下降。纳米碳管的加入并没有改变PP的结晶形态,碳纳米管/聚丙烯复合材料的结晶形态仍属于α晶型。     

一步法电沉积制备纳米金/碳纳米管修饰电极及对邻苯二酚电催化性能研究

以羧基化碳纳米管(CNT-COOH)溶液作为支持电解质,采用多电位阶跃电沉积方法将CNTs和纳米金同步直接沉积到玻碳电极表面,制备了对邻苯二酚(CAT)具有很高的电催化氧化作用的纳米金-碳纳米管修饰电极(Au/CNTs/GCE),其催化效果强于单独的金纳米粒子或碳纳米管修饰电极。通过优化沉积时间、pH和扫速对修饰电极的影响,并考察了在最佳条件下CAT在Au/CNTs/GCE修饰电极上的电化学行为,发现CAT在该修饰电极上发生可逆的氧化还原反应,响应电流与浓度在4.0×10-6～8.0×10-5mol/L和1.0×10-4～1.0×10-3mol/L范围内呈线性关系,相关系数分别为0.9996和0.9985,检出限为4.5×10-7mol/L(S/N)。     

碳纳米管用催化剂的大规模合成

在控制合成碳纳米管的过程中,其中一个非常关键的问题是:能否找到一种简单的途径合成可以控制粒径大小的纳米催化剂。一种通过有机方法合成纳米铁粒子催化剂的实验已经试验成功。在该试验中,用氧化镁作为基体,直径介于9.5~31nm之间的纳米铁微粒作为催化剂,乙醇和环己烷作为两种不同的碳源分别采用化学气相沉积对合成大规模碳纳米管进行了研究。在实验过程中,乙醇和环己烷两种不同碳源的裂解温度均控制在650~850℃之间。同时在该试验中没有使用其他的气体,在这样的条件下成功合成了管径非常小(19.5nm±2.5nm)的多壁碳纳米管。实验还通过X射线衍射对多壁碳纳米管的组成进行了分析,同时通过共振拉曼光谱和高分辨透射电子显微镜对样品进行了表征。     

ZnO纳米粒子的合成与表征

以乙醇为溶剂,乙酸锌为前驱物,聚乙烯吡咯烷酮为表面修饰剂,采用溶液化学法,制备了氧化锌纳米粒子。考察反应时间、聚乙烯吡咯烷酮加入量及含水量的影响。通过UV-Vis、FL和TEM等对ZnO纳米粒子进行表征。结果表明,在PVP-乙醇反应体系中加入3 m L浓度33.4 mmol/L乙酸锌水溶液,3 m L水,0.5 g PVP,在80℃反应120 min时,制得氧化锌纳米粒子的效果较好,氧化锌纳米粒子呈规则的球形,具有较好的分散性,粒径约为200 nm,且具有较窄的尺寸分布,证明PVP对ZnO纳米粒子表面具有较好的修饰效果。     

三苯基膦稳定金纳米粒子的合成及其特性研究

在水/乙醇混和体系中制备了三苯基膦稳定的金纳米粒子(GNPs)溶液。GNPs的粒径为5 nm,在548 nm有典型的表面等离子吸收。在不使用其它相转移分子的情况下,GNPs可以容易地转移到有机溶剂如二氯甲烷中,并得到可再分散于有机溶剂或水中的固体粉末,为制备可应用于不同的物理化学环境中的表面功能化GNPs提供了优异的初始化合物。     

Electrophoretic deposition of electroless nickel coated YSZ core-shell nanoparticles on a nickel based superalloy

In this work, yttria-stabilized zirconia (YSZ) nanoparticles were covered by a thin Ni layer with approximately 10 nm thickness by electroless deposition method to reduce sintering temperature of the ceramic coating which was applied on a Ni based superalloy via electrophoretic deposition (EPD). Suspensions containing the processed Ni-YSZ core-shell nanoparticles in acetone and isopropyl alcohol solvents were stabilized by addition of 0.4 wt% iodine and 1.5 wt% polyethylenimine, respectively, to find more effective stabilization method for EPD. It was seen that the presence of the Ni layer on YSZ nanoparticles improved performance and sticking factor of EPD and uniform coatings were obtained in both suspensions. The Ni-YSZ green coating which was produced by EPD at voltage of 35 V and deposition time of 30 min in acetone with thickness of 41 μm was sintered in 1100 °C and finally a uniform NiO-YSZ coating was formed on the metallic surface.     

辣椒红油膏中有机溶剂残留的测定方法

以甲醇、乙醇、丙酮为标准液,毛细管柱作分离柱,顶空气相色谱法测定辣椒红油膏中的溶剂残留。3种溶剂在0~2 000μg范围内线性关系良好(R=0.999 6~0.999 8);样品最低检测限为1.67 mg/kg;甲醇、乙醇、丙酮的回收率分别为91.7~109.7%、92.7%~105.4%、91.4%~105.9%。甲醇、乙醇、丙酮的RSD分别为2.86%~5.79%、2.98%~4.75%、2.68%~4.96%。     

溶剂脱毒汽爆玉米秸秆对酶解以及发酵的影响

以脱毒对酶解及发酵的影响为研究对象,以酶解还原糖得率及发酵乙醇质量浓度为指标,采用溶剂萃取的方法对无催化汽爆玉米秸秆进行萃取脱毒。结果表明,酶解还原糖得率随着萃取剂及萃取方式介于34.85%和89.7%,酶解还原糖得率和发酵乙醇质量浓度与脱毒有机溶剂的沸点高度负相关,表明有机溶剂的残留是导致酶失活的主要原因。而对于所考察的溶剂,乙醇产率为0.47～0.49 g乙醇/g还原糖,表明有机溶剂残留对乙醇发酵并无显著影响。采用乙醚和丙酮的组合萃取,乙醇最高产率可以达到理论值的96.1%。     

Synthesis of spherical NiO nanoparticles using a solvothermal treatment with acetone solvent

Nanometer-sized nickel oxide (NiO) particles were synthesized by thermal reactions with nickel (II) carbonate as a metal-containing precursor and four solvents: water, ethanol, butanol, and acetone. The optimal reaction conditions to obtain spherical NiO were determined to be the acetone solvent, nickel carbonate precursor, and a reaction temperature and time of 200 °C and 48 h, respectively. TEM images revealed perfectly spherical NiO nanoparticles of size ranging from 2.0 to 10.0 nm in the acetone solvent. The reaction mechanism for the formation of the NiO nanoparticles is proposed based on a pathway of chelated Ni complex during crystal growth. Although metallic Ni was also formed from reactions using the two alcoholic solvents, the Ni(OH)₂ structure remained in the water solvent after thermal treatment.     

藻类叶绿素a提取的优化研究

叶绿素a是参与光合作用的基础物质，是衡量水体藻类生物量以及评价湖泊富营养化的重要指标之一。利用90%丙酮、无水乙醇、无水乙醇∶90%丙酮（1∶1）、无水乙醇∶90%丙酮（1∶2）、无水乙醇∶90%丙酮（2∶1）五种有机溶剂萃取已知浓度标准叶绿素a和叶绿素b，对传统萃取叶绿素a的计算公式加以修正，并且在超声辅助破碎藻细胞的前提下分析了该五种有机溶剂对普通小球藻和铜绿微囊藻中叶绿素a的萃取效果。确定了无水乙醇∶90%丙酮（2∶1）的萃取效果最好，而无水乙醇从效果、安全、环保等角度考虑为最优溶剂。通过多参数水质监测仪对不同时间段的浅水型湖库水体中的叶绿素a进行监测，验证了在超声条件下无水乙醇测定结果的准确性并利用正交实验确定出了无水乙醇萃取叶绿素a的最佳条件。对于叶绿素a测定的优化研究使得以后野外水体大量测量叶绿素a的过程变得更为简便、快捷、准确。     

不同方法及溶剂对黄连小檗碱的提取效果比较

本文采用3种不同方法,分别以乙醇、丙酮、水作为提取溶剂对黄连小檗碱进行提取.以盐酸小檗碱作为对照,用标准曲线法测定各种溶剂及方法提取液中黄连小檗碱的提取率.实验结果表明:采用回流提取法,提取溶剂为乙醇,黄连小檗碱的提取率达到81%以上,标准偏差为0.0005,相对标准偏差为0.06%     

Water-Gas Shift Reaction in a Microchannel Ni-based Catalytic Coated Reactor: Effect of Solvents

Medium-temperature shift (MTS) reaction was investigated in a microchannel reactor using the electrophoretic deposition (EPD) method to coat porous layers of Ni-K/CeO₂ catalyst on stainless-steel plates. The electrolyte suspensions of the catalyst were prepared in isopropanol, ethanol, methanol, and acetone as solvents. All EPD experiments were carried out under similar conditions (i.e., for a contact time of 3 min, at a voltage of 140 V, and in the presence of 0.3 wt % polyethylenimine as the dispersant). The effect of the different solvents on the coated catalytic layers was studied using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and 2D and 3D optical imaging. The experimental results proved that the best performance for the MTS reaction in the plate microreactor was achieved with isopropanol as the solvent.     

Antisolvent effect on the crystallization of fosfomycin phenylethylamine by acetone: Solubility measurement and thermodynamic mechanism analysis

Antisolvent crystallization of fosfomycin phenylethylamin (FPEA) by acetone is demonstrated by measuring its solubility in binary solvents of (ethanol + acetone) and (water + acetone) at 293.15 K. The solubility (g/g) of FPEA always decreased with the increase of acetone composition and correlations were proposed to sufficiently represent the data. Excess solubilities (mole fraction) of FPEA were always positive with maximum and well correlated by the simplified-modified-Wilson equation. Effects of various solvent properties on the solubility were analyzed by the solvatochromic KAT linear solvation energy relationship, which revealed the decrease of solvent's hydrogen bond donation ability should be the most essential characteristics of the antisolvent. Finally, by analyzing its surrounding solvent composition using the inverse Kirkwood–Buff integrals method, we found FPEA was preferentially solvated by water in acetone–water due to the strong acidic behavior of water, while, because of different competing interactions in acetone–ethanol, FPEA was preferentially solvated by acetone in ethanol-rich region while by ethanol in acetone-rich region.     

Effect of solvents on inhibition of collagen-bound proteases by chlorhexidine

Chlorhexidine (CHX) incorporation during dentine bonding with dental adhesives enhances bond durability. Choosing an appropriate solvent for CHX to enhance resin–dentine bond durability is important. This study was conducted to examine the effect of solvents on the inhibition of dentine collagen-bound proteases by chlorhexidine. The inhibitory effects of CHX (0.2% and 2%) incorporated in three different solvents (water/ethanol/acetone) on the inhibition of dentine matrix-bound proteases were investigated by assessing the change in dry mass of demineralized dentine beams and the release of solubilized collagen peptides after 30 days. Solvents without CHX were used as controls. The beams treated with 2% CHX exhibited significantly lesser loss of dry mass and hydroxyproline release when incorporated in ethanol than in water (p<0.05). No significant difference in the inhibitory effect on dentine matrix-bound proteases was found between 0.2% and 2% CHX (p>0.05). The incorporation of 2% chlorhexidine in ethanol showed greater inhibitory effect on dentine matrix-bound proteases than in water.