Mg／A1型水滑石吸附硼的实验研究

采用共沉淀法制备了几种不同摩尔比的镁铝水滑石（LDHs）,并对其进行了XRD．FT-IR表征．将其应用于吸附溶液中的硼,比较了它们对硼的吸附容量,最终选择了具有较高吸附容量的Mg4Al-LDH作为硼吸附剂．对Mg4Al-LDH吸附硼的实验条件进行了系统研究,得到了较高吸附容量下的实验条件．试验结果表明该等温吸附过程可用Langmuir吸附等温模型准确描述．     

水滑石的合成及修饰电极的电化学行为

采用共沉淀法合成了摩尔比为3∶1的镍铝、钴铝、镁铝碳酸型水滑石。采用循环伏安法对其所修饰的玻碳电极的电化学行为进行了研究,结果表明仅有镍铝水滑石所修饰的玻碳电极具有较好的电化学行为。     

环境化学综合设计实验:镁铝水滑石的制备、表征及其对水中消毒副产物的吸附作用

制备了一种双金属氢氧化物吸附剂并对其溴酸盐吸附性能进行了测试,将吸附技术和现代测试技术与环境化学实验教学相结合。采用水热合成法制备了镁铝水滑石（MgAl-LDHs）吸附剂,焙烧后制得具有“记忆效应”的焙烧水滑石（MgAl-CLDHs）,并通过X射线粉末衍射（XRD）、傅里叶红外光谱仪（FT-IR）、热重（TG）及扫描电子显微镜（SEM）表征了吸附剂的结构和形态。结合材料的表征数据及性能测试结果分析探讨镁铝水滑石对溴酸盐的吸附效果,进一步探究该吸附反应的机制。该实验可让学生获取吸附领域的前沿知识,了解吸附反应以及各种现代测试技术的基本原理,提高学生的综合实验能力,激发独立思考和创新的意识,有利于创新人才的培养。     

MgZnAl-EDTA柱撑水滑石的制备及其对Pb(Ⅱ)的吸附

以共沉淀法合成的Mg2ZnAl-CO3水滑石为前体,采用离子交换插层组装方法制备了Mg2ZnAl-EDTA柱撑水滑石,并用XRD和IR进行表征。以水滑石前体和柱撑水滑石为吸附剂,用于废水中Pb2+的吸附。柱撑水滑石的吸附容量明显大于水滑石前体,柱撑水滑石的最佳吸附条件为:温度45℃,pH 5.5,吸附时间150min,Pb2+初始浓度100 mg·L-1。在最佳吸附条件下,柱撑水滑石对废水中Pb2+的饱和吸附量为183.51 mg/g。     

谷氨酸插层水滑石吸附水中铅离子

采用共沉淀法合成了谷氨酸插层镁铝类水滑石(LDH),对所制备的试样进行了X-射线衍射和红外光谱表征,对LDH去除水中铅离子的能力进行了讨论,研究了吸附过程的吸附动力学和吸附等温线。结果表明,谷氨酸能嵌入镁铝水滑石的层间,该插层水滑石能有效吸附水中铅离子,吸附过程符合准二级动力学模型,吸附等温曲线可用Langmuir模型来描述,吸附量可达68.49mg/g。     

镁铝水滑石负载MnO-4催化氧化乙苯合成苯乙酮

采用焙烧还原法制备了镁铝水滑石负载MnO4-催化剂,并将其应用于催化氧气氧化乙苯合成苯乙酮的反应中。考察了催化剂用量、反应温度、反应时间、MnO4-负载量和镁铝比等因素对催化氧化反应的影响及催化剂的重复使用性能。在优化条件下:催化剂用量3 g,乙苯用量45 mL,反应温度120℃,水滑石结构中n(Mg)/n(Al)=5,氧气流量100 mL/min,苯乙酮产率可达57.0%,苯乙酮选择性可达96.3%,催化剂重复使用3次催化活性降低较小。     

可充镁电池有机电解液Mg(SnPh3)2的研究

合成了可用于可充镁电池的一种新型电解液Mg（SnPh3）2,其分解电压为1.2V（相对Mg参比）。循环伏安、交流阻抗和电化学性能测试结果表明用它作为可充镁电池的电解液,电池有较好的循环性能。     

反相气相色谱法探究铜镁铝水滑石的表面性质

采用共沉淀法合成了Cu_xMg_3-xAl-LDHs (x＝0～3), 利用FTIR 及IGC 法(反相气相色谱法)对合成的样品进行测试和表征, 并结合计算机模拟的结果来探讨铜镁铝水滑石的表面性质. 结果表明, 随 Cu²⁺含量的增加, 铜镁铝水滑石表面吸附自由能及表面能色散组分增加, 稳定性下降, 这可能由于Cu²⁺本身具有的Jahn-Teller 畸变会很大程度地影响层板的稳定性, 导致含铜水滑石体系的稳定性降低; 随着Cu²⁺含量的增加, 水滑石表面碱性先减小后增大.     

吡唑基镁卤化物/四氢呋喃可充镁电池电解液

将不同配比的吡唑与格氏试剂反应制得的吡唑基镁卤化物/四氢呋喃（THF）溶液用作可充镁电池电解液,采用循环伏安和恒电流充放电测试研究了该电解液的镁沉积-溶出性能和氧化分解电位;并通过X射线衍射（XRD）和扫描电镜（SEM）对沉积物的组分和形貌进行了分析. 结果表明,吡唑上的取代基、吡唑与格氏试剂的反应配比对电解液的电化学性能都有影响. 1 mol·L^-1 1-甲基吡唑-PhMgCl（1：1摩尔比）/THF反应配制的电解液在不锈钢（SS）集流体的阳极氧化分解电位达到2.4 V（vs Mg/Mg²⁺）,并具有镁沉积-溶出电位低、循环稳定性高、配制方便的特点,有希望应用于实际的可充镁电池体系中.     

阴-非离子表面活性剂复合改性水滑石的表面性质研究

采用十二烷基苯磺酸钠(SDBS)、吐温-80(Tween-80)及两种表面活性剂复合改性镁铝水滑石,得到SDBS-LDHs,TweenLDHs及SDBS/Tween-LDHs 3种改性水滑石。利用反相气相色谱法(IGC)对样品进行表面性质的研究,定量计算了表面吸附自由能(ΔG0)和表面能色散组分(γs d)。结果表明,改性材料的ΔG0与γs d值均比未处理的镁铝水滑石小,其中阴-非离子表面活性剂复合改性后的水滑石的ΔG0与γs d值最小,说明阴-非离子表面活性剂复合改性水滑石较单一改性水滑石更有利于提高材料的稳定性。此外,各类水滑石的γs d值均随着温度的升高而减小,因此,在制备聚合物/水滑石类材料时,可以利用提高温度来改善其与聚合物的相容性。     

Coated wire thorium ion selective electrode: Part II

Thorium ion selective coated wire electrode (Th-ISE) developed in this laboratory was investigated for interference from most likely impurity ions like Fe(III), U(VI), Ca(II) and Mg(II) and corresponding selective coefficient were obtained. The Th-ISE electrode was also used for the end point detection of Th-EDTA titration for Th determination in the range of 3–6 mg and the accuracy and the precision of the results obtained was within ±0.5%.     

Electrochemical Determination of 2‐Nitrophenol in Water Samples Using Mg‐Al‐SDS Hydrotalcite‐Like Clay Modified Glassy Carbon Electrode

A glassy carbon electrode (GCE) modified with Mg‐Al‐SDS hydrotalcite‐like clay (SDS‐HTLC) was used for the sensitive voltammetric determination of 2‐nitrophenol (2‐NP) utilizing the oxidation process. The results indicate the prepared modified electrode has an excellent electrocatalytic activity toward 2‐NP oxidation, lowering the oxidation overpotential and increasing the oxidation current. Under optimal conditions, the oxidation current was proportional to 2‐NP concentration in the range from 1.0×10^?6 to 6.0×10^?4 M with the detection limit of 5.0×10^?7 M by DPV (S/N=3). The fabricated electrode was applied for 2‐NP determination in water samples and the recovery for these samples was from 95.6 to 103.5%.     

A metallic cobalt electrode for the indirect potentiometric determination of calcium and magnesium in natural waters using flow injection analysis

A flow injection analysis of Ca(2+) and Mg(2+) using indirect potentiometric detection in natural waters is proposed, where Ca(2+) or Mg(2+) are injected into a buffer carrier containing phosphate, resulting in the formation of Ca(3)(PO(4))(2) or Mg(3)(PO(4))(2). The consequent reduction in free phosphate in the carrier solution is detected using a metallic cobalt wire electrode. Indirect electrode response was used and the experimental conditions affecting electrode response were optimized. Responses were linear in the concentration range 5x10(-4) to 5x10(-3) M with a detection limit of 1x10(-5) M in 20 mM phosphate buffer at pH 8.0. The relative standard derivation at 1 mM of Ca(2+) and Mg(2+) were 3.9 and 3.7% (n=10), respectively. EGTA and 8-hydroxyquinoline were used as the masking agents for Ca(2+) and Mg(2+), respectively. Concentrations of Ca(2+) and Mg(2+) in natural waters were successfully determined by the proposed method.     

Lead ion-selective electrodes based on polyphenylenediamine as unique solid ionophores

A novel membrane electrode for Pb(II) ion detection based on semi-conducting poly(m-phenylenediamine) microparticles as a unique solid ionophore was fabricated. The electrode exhibited significantly enhanced response towards Pb(II) over the concentration range from 3.16 × 10⁻⁶ to 0.0316 M at pH 3.0-5.0 with a low detection limit of 6.31 × 10⁻⁷ M, a high sensitivity displaying a near-Nernstian slope of 29.8 mV decade⁻¹ for Pb(II). The electrode showed a long lifetime of 5 months and a short response time of 14 s. A systematical investigation on the effect of anion excluder and various foreign ions on the selectivity of the electrode by a fixed interference method suggests that all other metal ions hardly ever interfere with the determination of Pb(II) except high concentration Hg(II). The electrode was successfully used as an indicator electrode in the potentiometric titration of Pb(II) with EDTA. Furthermore, the electrode has been used to satisfactorily analyze four types of real-world samples like spiked human urine, spiked tap water, and river water containing interfering ions like Na(I), Ca(II), Mg(II), Zn(II), Pd(II), Fe(III), K(I), Cu(II) and Hg(II) up to 8.04 × 10⁻⁴ M, demonstrating fast response, high selectivity, good recovery (96.6-121.4%), good repeatability (RSD 0.31-6.45%), and small relative error (5.0%).     

Determination of hardness in tapwater and upland soil extracts using a long-term stable divalent cation selective electrode based on a lipophilic acrylate resin as a membrane matrix

A divalent cation-selective electrode, which utilizes a lipophilic resin as a matrix for the sensing membrane, and which has long-term stability has been developed. The sensing membrane is a lipophilic acrylate resin which is impregnated with a solution of 1-decylalcohol and the calcium salt of bis[4-(1,1,3,3-tetramethylbutyl) phenyl] phosphate at concentrations of 0.08 g ml(-1) each. The electrode exhibited nearly equal selectivity to Ca(2+) and Mg(2+) ions and could be used as a water hardness sensor. The electrode shows a Nernstian response with a slope of 29 mV decade(-1) to both Ca(2+) and Mg(2+) ions in the concentration range from 10(-5) M to 10(-1) M and could be used in the pH range from 3 to 10 for the determination of 10(-3) M Ca(2+) and Mg(2+) solutions. The initial performance of the electrode could be maintained for 1 year, since the lifetime test of the electrode was conducted in tapwater at a continuous flow rate of 4 ml min(-1). The hardnesses of tapwater and upland soil extracts were determined using the developed electrode and the analytical results were in good agreement with those obtained by chelatometric titration using an EDTA solution as the titrant. A coefficient factor of correlation 0.998 was obtained between the electrode method and titrimetry. The long-term stability of the electrode was found to be due to strong affinity of 1-decylalcohol to the lipophilic acrylate resin.     

Applications of Ytterbium in organic light-emitting devices as high performance and transparent electrodes

Potential applications of Ytterbium (Yb) in cathode system for organic optoelectronic/electronic devices were explored in NPB/Alq₃ based bi-layer organic light-emitting devices (OLEDs). When a thin (14.5 nm) Yb layer capped with a thicker (200 nm) Ag layer was used as the cathode, the OLEDs show enhanced electron injection over those using the standard Mg:Ag cathode. Performance of the OLEDs with the Yb/Ag cathode is comparable to that using LiF/Al cathode. Interestingly, we also found that Yb can also be used to prepare a highly transparent cathode by co-evaporating Yb and Ag to form a Yb:Ag alloy electrode. Surface-emitting (or top emission) and transparent (emission from both surfaces) OLEDs with low turn-on voltage (3.75 V) and high efficiency were prepared with the Yb:Ag electrode.     

Mn、Mg共掺杂Ni(OH)2的电化学性能

采用缓冲溶液法制备复合掺杂Mn、Mg的正极材料Ni0.82Mn0.18-xMgx(OH)2(x=0.06、0.09、0.12)。采用XRD、XPS和SEM等测试表征材料的晶体结构、锰价态和形貌,采用循环伏安和恒流充放电测试研究Mn、Mg不同掺杂比例对氢氧化镍电化学性能的影响。结果表明,Mn、Mg掺杂样品均为β相,晶粒细化;Ni0.82Mn0.09Mg0.09(OH)2样品具有优异的电极反应可逆性和充放电性能,100 mA·g^-1电流密度下的放电比容量(290.6 mAh·g^-1)优于商用β-Ni(OH)2(281.1 mAh·g^-1);且500 mA·g^-1电流密度下循环30圈后,Ni0.82Mn0.09Mg0.09(OH)2的放电比容量未见衰减,其循环稳定性优于商用β-Ni(OH)2。     

Electrophoretic Deposition: A Quantitative Model for Particle Deposition and Binder Formation from Alcohol-Based Suspensions

We investigated electrophoretic deposition from a suspension containing positively charged particles, isopropanol, water, and Mg(NO(3))(2), with the aim of describing the deposition rates of the particles and Mg(OH)(2), which is formed due to chemical reactions at the electrode, in terms of quantitative models. LaB(6) particles were used as a model system. The particle layer is consolidated by simultaneous precipitation of Mg(OH)(2) which acts as a binder to hold the particles together. The Mg(OH)(2) content was determined solely by the amount of charge passed through the cell. Quantitative precipitation of all OH(-) formed at the electrode was observed, except at very low current. The occurrence of a minimum current was ascribed to a threshold for Mg(OH)(2) deposition. The same minimum current was observed for particle deposition. In combination with results using NaNO(3), where no adherent layer was formed, this illustrates that Mg(OH)(2) binder is necessary for consolidation. Once the minimum current was exceeded, it was found that all particles that migrate to the electrode under the influence of the electric field contribute to the formation of the layer, i.e., the "sticking coefficient" for the particles equals 1.0. The applicability of the particle and Mg(OH)(2) deposition models was tested by variation of the Mg(NO(3))(2) concentration, pH, and water content. Copyright 2000 Academic Press.     

Electrochemical formation and phase control of Mg-Li alloys

The electrochemical formation of Mg-Li alloys was investigated in a molten LiCl-KCl(58-42 mol%)eutectic melt at 723 K. The cyclic voltammogram for a Mo electrode showed that the electroreduction of Li~ proceeds in a single step and the deposition potential of Li metal was -2.40 V(vs.Ag/AgCl).For Mg electrode,the electroreduction of Li~ takes place at less cathodic potential than that at the Mo electrode which was caused by the formation of Mg-Li alloys.Phase of the deposited Mg-Li alloys could be controlled by the electrolysis potential,and the samples were characterized by X-ray diffraction and scanning electron microscopy. The results showed thatα-Mg andβ-Li phases were obtained at -2.35 and -2.55 V,respectively.     

Electro-catalytic role of insulator/conductor interface in Mg O/PEDOT composite electrodes for dye-sensitized solar cells

Mg O has not been explored as a counter electrode materials for dye-sensitized solar cells(DSSCs)due to its lack of electrical conductivity.However,herein,it is reported that Mg O insulator with conductive poly(3,4-ethylenedioxythiophene):polysty-renesulfonate(PEDOT:PSS)exhibited excellent performance as a counter electrode for DSSCs,leading to a high power conversion efficiency of 7.45%.Furthermore,it was revealed that the interface between Mg O and PEDOT:PSS plays an important electro-catalytic role in the Mg O/PEDOT composite counter electrodes.