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31.
以自制的谷氨酸-氟硼酸(GluBF4)离子液体水溶液为反应介质,以物质的量比为1∶6的二水合醋酸锌[Zn(Ac)2·2H2O]和NaOH为原料,室温(25℃,20min)制备前驱体,再微波辅助加热(80℃,10min)制备了纳米氧化锌粉体,获得了纳米结构微米尺寸ZnO绒球。利用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)、比表面积(BET)、能谱(EDS)等对产物进行了表征。结果表明,所得产物为六方晶系纤锌矿结构,粉体粒径20.4nm,绒球比表面积为27.6m2/g。该纳米材料具有较高的光催化降解有机污染物活性。以紫外光为光源,50 mg微/纳米ZnO绒球为光降解催化剂,取500mL北京雪莲羊绒股份有限公司排污口混合印染污水进行光降解实验,在30min内光降解效率达到了100%,催化剂可回收重复利用,并对光降解机理进行了初步分析。 相似文献
32.
《Journal of the European Ceramic Society》2021,41(15):7723-7733
Lithium-ion batteries are currently the alternative of choice to overcome the increasing demand of energy. However, besides the scarcity of lithium and limited geolocation, it is believed that such batteries have already reached their maximum maturity. Sodium batteries emerge as an alternative to produce the new, so called, post-lithium batteries. In this study, we explore (i) the effect of sodium content and sintering temperature in solid electrolytes based in NASICON-type compounds and (ii) the use of two methodologies to obtain porous NASICON samples: application of natural substances and organic materials as pore-formers and freeze casting. The main purpose is the attainment of hybrid quasi-solid state electrolytes, with enhanced room temperature conductivity, based on porous ceramic electrolyte layers infiltrated with ionic liquids. Using this approach, porous samples with different microstructure and porous morphology and distribution were achieved, providing an enhancement in conductivity (ranging from 0.45 to 0.96 mS cm−1 at 30 °C) of one order of magnitude for infiltrated samples respect to pore-free samples. According to these results the porous NASICON might be considered as a functional macroporous inorganic separator that can act as a Na+ reservoir. 相似文献
33.
本文主要介绍了碳钢双层辉光离子镍铬共渗的试验结果,探讨了渗层厚度与镍铬共渗工艺参数的关系。试验表明,镍铬共渗层厚度取决于共渗温度、保温时间和试样材料,其变动范围0~300μm,共渗层中的镍铬含量可在0~90%的范围内变动。此外,还列举了双层辉光离子镍铬共渗工艺在碳钢钢板及碳钢零件上的应用。 相似文献
34.
影响取代咪唑阳离子C2-H酸性(pKa)的重要因素有二:H原子所带的部分正电荷和取代基的立体屏蔽效应,前者可用C2-H的1H NMR化学位移δC2-H度量,后者用基团拓扑立体效应指数TSEI衡量.咪唑阳离子C2-H的pKa可由以下方程估算:pKa=58.10-4.208δC2-H+1.659TSEI该式的标准偏差只有0.28 pKa单位,估算结果与文献报导的pKa值相吻合.表明如要精确估算pKa,必须考虑取代基立体屏蔽效应;当希望用碱性较低的亲核试剂脱除取代咪唑阳离子的C2-H形成卡宾时,应采用芳香基取代的咪唑离子;若使用取代咪唑离子液体作溶剂,并且在碱性较强的条件下进行有机反应,则最好选择立体屏蔽效应大的非芳香基取代的咪唑离子. 相似文献
35.
Jang-Woo LeeAuthor Vitae Young-Tai YooAuthor Vitae 《Sensors and actuators. B, Chemical》2011,159(1):103-111
A new ionic polymer actuator was prepared with Nafion®-117 membrane and electrodes made of an electrospun Nafion®/multiwalled carbon nanotube (MWNT) web. The surfaces of composite electrodes were ion-beam coated with gold layers of 2-3 μm thickness to reduce the surface resistance. The composite electrodes offer several advantages over conventional platinum electrodes prepared via electroless plating process, i.e. flexibility, simple processability in large scales, and batch-to-batch reproducibility. The new ionic polymer-metal composite (IPMC) actuators showed a rapid and large bending motion. Under an applied potential of 3 V dc, the maximum horizontal displacement (δmax) measured at the tip of IPMC strip (cantilever length: 20 mm) was 16.7 mm, the tip velocity in the initial linear region was 10.5 mm/s, 88% of the δmax was reached within initial 5 s, and the generated strain% was 0.79 (13.6 mm, 7.2 mm/s, 85%, and 0.88, respectively for a conventional Nafion®-IPMC made via the electroless plating of platinum). It was noted that the energy efficiency of strain was over 10 times higher than that of the conventional Nafion®-IPMC. And the crack formation of metal electrode after repeated bending deformation significantly reduced with the introduction of relatively flexible electrode assembly into the IPMC architecture. The remarkable improvements in its performance were considered to be due to the efficient quantum chemical and double-layer electrostatic effects in a charge injection model, induced by the good dispersion of MWNTs through a typical electrospinning technique. 相似文献
36.
Yongyan TanAuthor VitaeJinqing KanAuthor Vitae Shengqi LiAuthor Vitae 《Sensors and actuators. B, Chemical》2011,152(2):285-291
A novel amperometric biosensor for the determination of catechol was developed accordingly to the electrochemical template procedure. The optimum fabricating conditions of the biosensor were studied. The resulting biosensor with the limit of less than 0.05 μM can be used for detection of catechol in the linear range of 2.5-140 μM. The maximum response current (Imax) and the Michaelis-Menten constant (k′m) are 3.08 μA and 77.52 μM, respectively. The activation energy (Ea) of the polyphenol oxidase (PPO) catalytic reaction is 25.56 kJ mol−1 in the B-R buffer. The stability of the PANI-CA biosensor fabricated with the electrochemical template process (retains 86% of the original activity after four months) is much higher than that fabricated with one-step and two-step processes (retains 75% of the original activity after four months). The effects of potential and pH on the response current of the biosensor are also described. 相似文献
37.
Sang Hyun Lee Sung Ho Ha Chun-Yeol You Yoon-Mo Koo 《Korean Journal of Chemical Engineering》2007,24(3):436-437
Recovery of 1-butyl-3-methylimidazolium tetrachloroferrate ([bmim]FeCl4) from its mixture with water was investigated. The [bmim]FeCl4 rich phase in the mixture forming two-phase was successfully separated, while homogeneous mixtures could not be separated.
However, the concentration of the homogeneous mixture varied as a function of the magnetic field strength. Therefore, a combination
of magnetic field and conventional methods to recover magnetic ILs from reaction mixtures will be very useful and have great
potential. 相似文献
38.
Abstract A regional study of Selenium (Se) speciation in surface waters, groundwaters, and saturation extracts from Soan-Sakesar valley Salt-Range, Pakistan was started in March 1994 and completed in October 1996. Groundwaters, streams, and springs had median concentrations of: total Se 48, 404.5, and 82 μg/l; Se+VI 40, 350 and 51 μg/l; Se+IV 8, 48 and 29 μg/l; Se-II 0, 6.5 and 2.0 μg/l, respectively. The concentration of Se exceeded the recommended water quality guidelines for drinking and irrigation water of 10 and 20 μg/l, respectively. In saturation extracts, median total Se, Se+VI, Se+IV and Se-II were 190, 146, 37 and 7.0 μg/l, respectively. Uchhali, Khabbaki and Jahlar lake water samples had the mean concentration of: total Se 2103, 670 and 297 μg/l; Se+VI 1777, 470, and 233 μg/l; Se+IV 291, 166 and 39 μg/l; Se-II 35, 34 and 25 μg/l, respectively. The Sakesar limestone Formation of Eocene age rich in shales and fossils (median Se concentration 7.2 μg/kg) are considered to be the source of selenium that have enriched soils of Soan-Sakesar valley. Selenim speciation results show the abundance of selenate in all the environmental samples. A linear relationship between Se+VI and pH (R2= 0.84, 0.58, 0.88, 0.82, and 0.91; significant at the 0.05 level) for groundwater, saturation extract, stream, spring, and lake waters were noted, suggesting that the Se+VI in the samples is highly associated with pH. Linear relationships were established between Se+VI and Mg, NO3, and SO4 for groundwater (R2= 0.24, 0.16, and 0.64; significant at the 0.01 level) and surface water (R2= 0.96, 0.14, and 0.91; significant at the 0.001 level). This suggests the high concentrations of Mg, NO3 and SO4, which strongly adsorb and compete with selenium for surface site, increases the Se+VI fraction. The results show that the higher percentage of selenate on other species in the analyzed samples is favored by higher pH and oxidizing environments of the valley. 相似文献
39.
40.
Hyun-Soo Kim Sung-Il Kim Chang-Woo Lee Seong-In Moon 《Journal of Electroceramics》2006,17(2-4):673-677
In this work, LiNi1/3Mn1/3Co1/3O2 powders were synthesized from co-precipitated spherical metal hydroxide. In the voltage range of 2.8–4.2, 2.8–4.4, and 2.8–4.6
V, the discharge capacities of LiNi1/3Mn1/3Co1/3O2 electrode were 163, 177, and 193 mAh⋅g−1, respectively. A gel polymer electrolyte (GPE) was also prepared using polyoxyalkylene glycol acrylate (POAGA) as a macromonomer.
LiNi1/3Mn1/3Co1/3O2/GPE/graphite cells were prepared and their electrochemical properties were evaluated at various current densities and temperatures.
The ionic conductivity of the GPE was more than 6.2 × 10−3 S⋅cm−1 at room temperature. POAGA-based cells were showed good electrochemical performances such as rate capability, low-temperature
performance, and cycleability. 相似文献