羧基化的MWNTs／Nafion／SiC修饰电极对痕量铅离子的测定

采用羧基化的多璧碳纳米管（MWNTs）、Nation及SiC对玻碳电极进行修饰,表面修饰效果采用电子显微镜进行表征,对测定条件进行了优化。并用修饰后的电极对实际水样中的铅离子进行差分脉冲阳极溶出伏安法测定。结果表明,在2．0×10-8．1．2×10-4mol·L-1范围内,峰电流与铅离子浓度成正比。线性方程为ip=3．0186×107C＋8．6165（ip的单位为μA;C的单位为mol·L-1）,R=0．9916,最低检测限为3．0×10-9mol·L-1（S／N=3）。同时考察了各种干扰离子及表面活性剂的影响,结果表示此电极测定铅离子效果较好,适用于对铅离子的测定。     

Ti基系列阳极的制备及电解染料废水实验研究

采用热氧化法制备了Ti／PbO2、Ti／SnO2-Sb2O3／PbO2、Ti／SnO2-Sb2O3／PbO2-Cu、Ti／SnO2-Sb2O3／PbO2-Ni和Ti／SnO2-Sb2O3／PbO2-Fe5种钛基系列阳极,进行电催化氧化处理模拟染料废水酸性品红溶液的实验研究,比较了不同电极的处理效率、反应速率,同时分析了酸性品红降解过程。结果表明：相对于Ti／PbO2和Ti／SnO2—Sb2O3／PbO2阳极,金属掺杂改性电极Ti／SnO2-Sb2O3／PbO2-Fe和Ti／SnO2-Sb2O3／PbO2-Ni对酸性品红有着更好的去除效率和降解速率,而Cu掺杂电极Ti／SnO2-Sb2O3／PbO2-Cu改性效果不明显。5种电极的电催化氧化过程均符合一级动力学模型。酸性品红在Ti／SnO2-Sb2O3／PbO2-Fe阳极上电催化氧化降解过程的紫外-可见光谱图表明在电流密度75mA／cm^2、电解质Na2SO4浓度12g／L的条件下,处理100mg／L的酸性品红模拟废水,60min内其特征吸收峰消失,酸性品红基本去除,但同时生成了部分小分子中间产物。     

Comparative study of oxidation ability between boron-doped diamond （BDD） and lead oxide （PbO_2） electrodes

The electrochemical oxidation capabilities of two high-performance electrodes,the boron-doped diamond film on Ti(Ti/BDD)and the lead oxide film on Ti(Ti/PbO2),were discussed.Hydroxyl radicals(·HO)generated on the electrode surface were detected by using p-nitrosodimethylaniline(RNO)as the trapping reagent.Electrochemical oxidation measurements,including the chemical oxygen demand (COD)removal and the current efficiency(CE),were carried out via the degradation ofp-nitrophenol(PNP)under the galvanostatic condition.The results indicate that an indirect reaction,which is attributed to free hydroxyl radicals with high activation,conducts on the Ti/BDD electrode,while the absorbed hydroxyl radicals generated at the Ti/PbO2 surface results in low degradation efficiency.Due to quick mineralization which combusts PNP to CO2 and H2O absolutely by the active hydroxyl radical directly,the CE obtained on the Ti/BDD electrode is much higher than that on the Ti/PbO2 electrode,notwithstanding the number of hydroxyl radicals produced on PbO2 is higher than that on the BDD surface.     

新型不锈钢基PbO2/PbO2-CeO2复合电极材料的研制

报道了在不锈钢基体上电沉积制备PbO2／PbO2-CeO2复合电极材料．研究了电沉积工艺参数对不锈钢表面沉积二氧化铅的影响．采用XRD、SEM对得到的电极进行了相结构和形貌分析，把该新型电极材料应用于电积锌过程并与传统的铅电极进行了对比，结果表明，采用不锈钢基PbO2／PbO2-CeO2复合电极材料，锌电积过程的槽电压降低，电流效率高．     

电解液组成对PbO2／PbSO4电极电化学行为的影响

用循环伏安法研究了电解液组成对ＰｂＯ２／ＰｂＳＯ４电极电化学行为的影响，并用实际电池加以对照．在电解液中加入Ｎａ２ＳＯ４、ＣｄＳＯ４、ＣｏＳＯ４和ＬＤ均可提高其放电容量，ＣｏＳＯ４可显著延长电池使用寿命．     

Effect of TiB_2 content on resistance to sodium penetration of TiB_2/C cathode composites for aluminium electrolysis

1　INTRODUCTIONInrecent years ,therehavebeenincreasingeffortstoimprovetheHall Heroult processintheprimaryaluminiumindustry[1 ] .InordertoovercometheshortagesofHall Heroultprocess ,suchashighconsumptionofelectricalpower ,highconsumptionofcarbonanodeandserious pollutionduetocarbonanodemanufactureandconsumptionetc ,anoveltypeofaluminareducedcellsbasedoninertanodeandwettablecathodesystemwasdevelopedtoreplaceconventionalHall Heroultprocess[2 ,3 ] .Titaniumdiboride(TiB2 )appearstobethebestca…     

Electrode selection of electrolysis with membrane for sodium tungstate solution

Abstrac By measuring the electrode polarization curves of many kinds of materials and life spans of electrodes through intensifying electrolysis in the process, the appropriate electrode materials for different stages of electrolysis of sodium tungstate solution with membrane have been selected The effects of the electrodes with different shapes on electrolysis have been investigated. The result shows that network electrode is more suitable to electrolysis of sodium tungstate solution. Project supported by the Key Program of the 9th Five-year Plan of China Synopsis of the first author Xiao Liansheng, associate professor, born in 1956, majoring in separation science and metallurgical engineering.     

无膜单液全沉积型铅酸液流电池研究进展

无膜单液全沉积型铅酸液流电池是以甲基磺酸中二价铅离子的电化学沉积/溶解反应为充放电基础的新型储能装置.归纳了全沉积型铅酸液流电池的反应机理和特点,介绍了电解液组成、添加剂选择、电极材料性能等对正负极二氧化铅和铅的电化学沉积/溶解过程和电池充放电性能影响的研究进展情况.     

Effect of TiB2 content on resistance to sodium penetration of TiB2／C cathode composites for aluminium electrolysis

TiB2/C cathode composites with various contents of TiB2 were prepared and their characterizations were observed and compared. The expansion of samples due to sodium and bath penetration was tested with a modified laboratory Rapoport apparatus and the appearances of the cut sections of specimens after electrolysis were studied.The results show that the mass of TiB2/C cathode composites with mass fraction of TiB2 less than 70% appreciably increases, but that of the composites with mass fraction of TiB2 more than 70% decreases slightly after being baked.The resistance to sodium and bath penetration of TiB2/C cathode composites increases with the increase of TiB2 content, especially in the composites with high TiB2 content. TiB2/C cathode composites have high resistance to the penetration of sodium and bath as well as good wettability by molten aluminum, and keep integrality and have little change of appearance after electrolysis, which indicates that TiB2/C cathode composites can be used as inert wettable cathode for aluminum electrolysis.     

钛基二氧化铅电极的制备及在电合成4-吡啶甲酸中的应用

钛基二氧化铅电极 (Ti/PbO2 )具有较好的耐腐蚀性和导电性 ,析氧过电位高且硬度大 ,是一种理想的不溶性阳极材料。该电极由半导体中间层和电沉积的二氧化铅组成 ,经过实验获得了最佳的电极制备参数。中间层Sb2 O3 的质量分数为 15 %～ 2 5 % ,电沉积液中的添加剂NaF可使PbO2 镀层致密 ,浓度为 0 .4mg/L ,pH值为 1～2 ,电流密度为 5 0mA/cm2 。将该钛基二氧化铅电极应用到电解氧化 4-甲基吡啶合成 4-吡啶甲酸的实验中 ,以反应的转化率、电流效率和电极的腐蚀速度为依据 ,考察了电极的活性、镀层的质量和电极寿命 ,并通过极化曲线评价了电极的导电性及X -衍射光谱表征了二氧化铅的晶型为 β-PbO2     

Vaporization behavior of lead from the FeO-CaO-SiO2-Al2O3 slag system

Vaporization behavior (1163–1463 K) of lead in the slag system of FeO-CaO-SiO₂-Al₂O₃ with CaCl₂ was examined. A thermodynamic estimation with the principle of Gibbs free energy minimization showed that the major vapor species from the sample of the FeO-CaO-SiO₂-Al₂O₃ system+PbO+CaCl₂ were metallic Pb, PbCl, PbCl₂, and FeCl₂, at the experimental temperature range. The experimental results show that the mole ratio of vaporized Cl in lead chlorides to vaporized Pb, simply expressed as Cl/Pb, decreases with increasing temperature. The larger Cl/Pb means a larger ratio of gaseous PbCl₂, since metallic Pb and PbCl vapors are formed in a similar reduction atmosphere. The evaporation is initially rapid and becomes steady after holding for 10 min. Gaseous PbCl₂ is mainly formed during the heating period, and at the holding stage, it reacts with FeO to produce gaseous FeCl₂. With regard to slag composition, FeO content and basicity significantly affect the evaporation of lead. High FeO content and high basicity promotes the formation of metallic Pb and PbCl, whereas, it prohibits PbCl₂ evaporation.     

Electro-oxidation treatment of Sn/PANI electrode and electrocatalytic activity of Pt/Sn hydroxide/PANI composite electrodes

After being electro-oxidized by cyclic voltammetry（CV） method in 0.5 mol/L H2SO4 solution or in 0.2 mol/L H2O2＋0.5 mol/L H2SO4 solution, the Sn/polyaniline （PANI） electrodes were modified with Pt microparticles by pulse galvanostatic method, thus Pt/Sn hydroxide/PANI electrodes were prepared. The electrocatalytic activities of the Pt/Sn/PANI electrode and Pt/Sn hydroxide/PANI electrode for formaldehyde electro-oxidation were investigated by CV method. The effects of deposition charges （Qdep） of PANI, Sn and Pt, scan rate and formaldehyde concentration on the electrocatalytic activity of Pt/Sn hydroxide/PANI electrode were also studied. The results show that the electrocatalytic activities of the Pt/Sn hydroxide/PANI electrodes are much higher than those of the Pt/Sn/PANI electrode.     

Cr~(3+)在Pb/PbO_2电极上的电化学氧化

研究了Cr3+在Pb/PbO2 电极上的电氧化 ,确定了铬离子电氧化的最佳条件 :Cr3+浓度 0 35mol·L- 1 ,电流密度 1 98A·m- 2 ,硫酸浓度 4mol·L- 1 ,温度 44℃ ,硫酸铵浓度0 1 5mol·L- 1 。在此条件下 ,铬离子转化率为 74 2 8%,电流效率为 94 5 7%。     

Vaporization behavior of lead from the FeO-CaO-SiO_2-Al_2O_3 slag system

Vaporization behavior (1163-1463 K) of lead in the slag system of FeO-CaO-SiO2-Al2O3 with CaCl2 was examined.A thermodynamic estimation with the principle of Gibbs free energy minimization showed that the major vapor species from the sample of the FeO-CaO-SiO2-AI203 system+PbO+CaCl2 were metallic Pb,PbC1,PbCl2,and FeC12,at the experimental temperature range.The experimental results show that the mole ratio of vaporized CI in lead chlorides to vaporized Pb,simply expressed as CI/Pb,decreases with increasing temperature.The larger CUPb means a larger ratio of gaseous PbCl2,since metallic Pb and PbCI vapors are formed in a similar reduction atmosphere.The evaporation is initially rapid and becomes steady after holding for 10 rain.Gaseous PbCI2 is mainly formed during the heating period,and at the holding stage,it reacts with FeO to produce gaseous FeCI2.With regard to slag composition,FeO content and basicity significantly affect the evaporation of lead.High FeO content and high basicity promotes the formation of metallic Pb and PbCI,whereas,it prohibits PbCl2 evaporation.     

类金刚石薄膜电极在污水处理中的应用

以类金刚石(DLC)薄膜作为电极进行污水处理时,具有比IrO2/Ta2O5钛涂层电极、PbO2等电极更好的氧化效果,这是由于DLC具有更宽的电势窗口和更低的背景电流.此外,DLC还具有耐酸、耐腐蚀以及低吸附特性等特点,不会在酸性、腐蚀性的污水中破损,因此比其他的电极更适合在污水中长时间工作.为此,对DLC的制备、DLC电极电化学性能的影响参数,以及DLC在污水处理中应用的研究成果进行了综述总结.     

Al/Pb-WC-ZrO2-Ag和Al/Pb-WC-ZrO2-CeO2 复合电极材料的性能研究

研究了Ag固体微粒对Al／Pb WC ZrO2 Ag复合电极材料电化学性能的影响、结果表明，银粉的质量浓度为3～4g／L时制得的Al／Pb WC ZrO2 Ag复合电极材料综合性能较好．研究Ce02固体微粒对Al／Pb WC ZrO2 CeO2复合电极材料电化学性能的影响，结果表明，当Ce02的质量浓度为10～20g／L时制得的A1／PbWCZr02Ce02复合电极材料相对较好．     

稀土修饰电极Pt - TiO2/Eu3+/C对CO电氧化的影响

为研究Pt—TiO2／C电极表面吸附稀土铕离子对CO吸附和氧化的影响,用循环伏安法研究了CO在Pt—TiO2／C,Pt-TiO2／Eu^3 ／C电极上的氧化,发现吸附稀土Eu^3 后,电极表面对CO的吸附明显减弱．CO在电极表面的氧化过电位减小,在酸性溶液中CO的起始氧化电位及氧化峰电位分别负移200mV和210mV;中性溶液中氧化峰电位负移380mV．Eu^3 在电极表面的吸附有利于CO在电极表面的氧化．     

棒状纳米PbO的固相合成

分别以 Pb(Ac)2·3H2O、 Pb(NO3)2 为原料,与 NaOH 在室温条件下进行固相化学反应,得到了纳米 PbO 粒子.通过在反应体系中添加 NaCl,成功地制得了棒状 PbO 纳米粒子.运用 X 射线衍射 (X-Ray Diffractomer,XRD) 和透射电镜 (Transmission Electron Microscope,TEM) 对产物进行了表征.研究表明,氯离子的存在对产物 PbO 的形貌有很大影响.     

An improved sensitivity non-enzymatic ascorbic acid sensor based on a Ag2O nanowire modified Ag electrode

In this paper, the Ag2O nanowires had been prepared and applied for the fabrication of ascorbic acid sensors with high enhanced sensitivity by using self-assembly technology. The structures and morphologies of Ag2O nanowires were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The direct electrocatalytic oxidation of ascorbic acid in alkaline medium at Ag2O nanowires modified electrodes had been investigated in detail and the condition for determination of ascorbic acid was optimized, such as support-electrolyte, pH and scan speed. The oxidation peak current changed linearly with the concentration of ascorbic acid over the range from 2.0×10-8 mol/L to 1.0 mmol/L, and the detection limit can reach 1.0×10-8mol/L. Compared to a bare Ag electrode, a substantial decrease in the overvoltage of the ascorbic acid oxidation was observed at the Ag nanowires electrodes with oxidation starting at ca. 0.7V vs. Ag/AgCl (saturated KCl). The Ag2O nanowires modified electrode allows highly sensitive, low working potential, stable, and fast amperometric sensing of ascorbic acid, thus is promising for the future development of non-enzymatic ascorbic acid sensors.     

STUDY ON PHOTOCATALYTIC MECHANISM OF SOL-GEL-DERIVED Pb-DOPED TiO_2 THIN FILMS

Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results showed that besides oxides of Ti(IV) there is a certain amount of oxides of To(Ⅲ) and Ti(Ⅱ) and Pb exists in the forms of PbTiO3 and PbO. The photocatalytic activity of the Pb-doped TiO2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange and photocatalytic mechanism mas also analyzed.