Formation of Mixed -Ligand Complexes of Zn(Ⅱ)in Solutions of Sodium Hydroxide and Triethanolamine or Ethylenediaminetetraacetate

[中文文摘]本工作用电位法研究溶液中Zn(Ⅱ)混合配体络合物的形成。实验结果表明,在氢氧化钠-三乙醇胺溶液中,Zn(Ⅱ)的主要络合品种为Zn(TEA)(OH)_2。在氢氧化钠-乙二胺四乙酸溶液中Zn(Ⅱ)的主要络合品种为[Zn(EDTA)(OH)_2]~(4-)。[英文文摘]Formation of mixed ligand complexes of Zn(II) was studied by means of potentiomctric determination. The experimental results show that the predominant complex species in NaOH-TEA solutions is Zn(TEA)(OH)2, and in NaOH-EDTA solutions-[Zn(ETDA)(OH)2]4-

Electrochemical Immobilization of HRP and Properties of HRP/ P OPD Enzyme Membrane Electrodes

利用电化学固定化方法制备含辣根过氧化物酶的聚邻苯二胺（HrP/P-OPd）膜电极，改变聚合用溶液的酸度和所含支持电解质的成分，研究酶的固定化过程及其对所得酶电极性能的影响.结果表明依电聚合条件而异，酶可能以不同途径进入聚合物基质中.支持电解质的品种会影响酶膜的形成速度、组成和稳定性.所得HrP/P-OPd膜电极可在溶液不含电子传递体的条件下催化H2O2的还原，电聚合过程中进入酶膜的寡聚体可能充当酶的电子传递体By the electrochemical immobilization technique , horseradish peroxidase was entrapped into poly o phenylenediamine to prepare the enzyme membrane electrodes. The mechanism of enzyme immobilization was studied with changing the acidity of polymerization solution and the kinds of supporting electrolytes, and the properties of the resulting enzyme electrodes were examined. The results show that,depending on the immobilization conditions, the mechanism of entrapment of HRP into the polymer matrix is diFFerent.The supporting electrolytes have great inFluences on the growth rate, composition and stability of the enzyme membrane. The resulting enzyme electrode exhibits the activity to catalyze the electroreduction of hydrogen peroxide in the absence of any electron transFer mediator in solution. It was illustrated that the oliogomers ,which is produced in the course of o phenylenediamine polymerization and then incorporated in the enzyme membrane, may play a role of electron transFer mediator.国家自然科学基金;国家教委博士点基

AC VOLTAMMETRIC AND IMPEDANCE STUDIES OF THE ELECTROCHEMICAL OXIDATION OF PYRROLE IN AQUEOUS-MEDIUM

The electropolymerization of pyrrole on platinum electrodes has been studied by ac voltammetric and impedance techniques. Anionic species such as chloride, bathophenanthroline disulfonate and ferricyanide, when present in solution during polymerization, adsorbed on the electrode surfaces and increased the rate of the electropolymerization process. The impedance responses of pyrrole solutions were also affected by the applied potential. These anionic species also became incorporated in the polypyrrole film as a result of chemical adsorption and electrostatic interaction

Electron TransFer of Horseradish Peroxidase Entrapped in Poly-o-phenylenediamine Membrane Electrode

利用酶的电化学固定化方法制备合辣根过氧化物酶的聚邻苯二胺膜电极，研究其伏安行为及对H2O2还原的生物电催化作用.结果表明，在所述生物电催化反应中酶与聚合物基质发生了直接电子传递.但对新制的酶电极而言，电聚合时生成并包理在酶膜中的寡聚体可作为电子传递体加速氧化态酶的再生.根据酶电极电流响应实验曲线的拟合，发现氧化态酶的再生速度随电极电位的变化表观上符合TAfEl关系式.提出了酶反应动力学参数的测定方法.The poly-o-phenylenediamine membrane electrode containing horseradish peroxi-dase was prepared by means of the electrochemical immobilization of enzyme, and thevoltammetric behavior of the resulting enzyme electrode and its bioelectrocatalysis to hydro-gen peroxide reduction was studied.It was Found that the direct electron tansFer between theenzyme and the polymer matrix takes place in the biocatalytic processes.For the newly pre-pared enzyme electrode, however, the oligomers, which are Formed during the polymeriza-tion of o-phenylenediamine and then incorporated in the enzyme membrane, can play a role ofelectron transFer mediators to accelerate the regeneration of the oxidized enzyme.From theFitting of experimental current response curves, it can be Found that the change in the regen-eration rates of the oxidized enzyme with the electrode potentials obeys apparantly the TaFelrelationship.The procedure in the measurement of kinetic parameters For enzyme reactionswas suggested.国家自然科学基金;国家教育委员会博士点基

CORROSION COMPOSITIONS OF CARBON STEEL UNDER ION-SELECTIVE COATINGS BY XPS

[中文文摘]用XPS分析不同离子选择性涂层下碳钢表层的化学组成 .结果表明 ,SO2 - 4 型阴离子选择性和Na+ 型阳离子选择性涂层下碳钢表面锈层的主要成分是含结合水的Fe(OH) 2 和少量FeO ,SO2 - 4 型阴离子选择性 /Na+ 型阳离子选择性双极涂层下碳钢表面的主要成分是Fe0 ,Fe2 + 所占比例很少 .在涂装阴离子选择性涂层的碳钢表面可以检测到比较明显的Cl- 的XPS信号 ,而在涂装阳离子选择性涂层和双极性涂层的碳钢表面则不明显 .[英文文摘]Ion-selective (anion-selective,cation-selective and bipolar) phenolic coatings were prepared by mixing phenolic varnish with ion exchangers.SO 2- 4-type anion exchanger resin and Na +-type cation exchanger resin were utilized as anion and cation exchangers respectively.The bipolar coating consisted of an anion-selective inner layer and a cation-selective outer layer.The corrosion compositions of carbon steel depriving of the painted ion-selective coatings after exposure in 3%NaCl solution for 30 days were investigated by XPS. The research result s of XPS showed that the main compositions in the surface layer of carbon steel are Fe2 + ,OH- ,O2 - and Cl- under SO2-4 - type anion - selective coating ,whereas the main compositions are Fe2 + , Fe0 , OH- ,and O2 - under Na + - type cation - selective and SO2 -4 - type anion - selective / Na + -type cation - selective bipolar coatings. The XPS signal of Cl - can be inspected obviously on the surface layer of carbon steel with anion - selective coating ,whereas there is no obvious signal in the case of cation - selective and bipolar coatings. This indicated that Cl - could migrate from the NaCl solution to the subst rate metal when carbon steel covered with anion - selective coating ,whereas the migration of Cl- would be blocked in the case of cation -selective and bipolar coatings. From these results ,it can be concluded that SO2-4 - type anion - selective coating has poor corrosion resistance , Na + - type cation - selective coating has better corrosion resistance , and SO2-4 -type anion - selective/ Na + - type cation - selective bipolar coating has excellent corrosion resistance

Electrochemical and Corrosion Behaviour of A3 Steel Covered With Ion selective Organic Coating

采用动电位扫描极化曲线和电化学交流阻抗技术，研究了A3钢表面涂装阴离子选择性、阳离子选择性和双极性有机涂层在3%nACl溶液中的腐蚀和电化学行为，分析了不同离子选择性涂层对A3钢防蚀性能的差别，并探讨了其耐蚀机理Potentiodynamic method and electrochemical impedance spectroscopy technique were empoloyed to study the corrosion electrochemical behaviour of A3 steel covered with anion selective、 cation selective and bipolar organic coating ,and phenolic varnish (nonionic selective organic coating) as contrast, in 3% NaCl solution.The results indicate that,compared with phenolic varnish,anion selective organic coating accelerates the propagation of metal corrosion,whereas cation selective organic coating decelerates corrosion propagation, and bipolar organic coating is of the most corrosion resistance among the Four type organic coatings.国家自然科学基金;中国科学院腐蚀与防护国家重点实验室课

Electrodeposition of Zn Deposits with Highly PreFerred Orientation

采用电沉积方法，在含kMnO4的znSO4溶液中，通过控电位和控电流，得到高择优取向的（0002）和（1011）zn沉积层.用X射线衍射技术和扫描电子显微镜进行表征.结果表明这种高择优取向的zn沉积层与相应的zn单晶具有相似的Xrd图，且具有比较完整的晶体结构，几乎不存在位错应力；还通过阴极极比曲线讨论了形成高择优取向zn沉积层的可能原因.Zn deposits with(0002)and(1011)highly preFerred orientation were obtained in the solution of 0.8 mol/L ZnSO4,0.5 mol/L H2SO4 and 4.0×10-4 mol/LKMnO4 by controlling tlie deposition potential or current.The deposits with highly preFerred orientation were studied by X-ray diFFraction and scanning electron microscope.The results showed that tl1e diFFraction patterns of the deposits with(0002)and(1011)highly preFerred orientation were very similar to tlie corresponding patterns of Zn single crystals.But there were little disloction stresses in the deposits.The eFFort was made to explain the reason For the deposits with highly preFerred orientation From the polarization curve of the solution.国家自然科学基

EFFECT of ION-SELECTIVE PHENOLIC COATINGS ON ELECTRO-CHEMICAL BEHAVIOUR of COPPER IN 3% NaClSOLUTION

利用掺杂离子交换体制备了含不同交换离子品种的阴离子选择性、阳离子选择性和双极性酚醛涂层,研究了涂装不同离子选择性酚醛涂层的铜电极在3%nACl溶液中的腐蚀电化学行为,讨论了各种离子选择性涂层对铜防护性能的差别,并与没有离子选择性的涂层作了比较。Anion-selective, cation-selective and bipolar phenolic coatings were prepared by mixing phenolic varnish with ion exchangers.MoO42- anion exchanger resin and ammonium molybdophosphate were utilized as anion and cation exchangers respectively.The bipolar coating consisted of an anion-selective inner layer on the metal side and a cation-selective outer layer on the solution side.The polarization curves and Nyquist plots of copper electrodes covered with various ion-selective phenolic coatings and nonionic-selective phenolic coating as contrast in 3% NaCl solution were measured by poltentio-dynamic method and EIS technique.The results indicated that, compared with the nonionic- selective coating, the anion-selective coating accelerated the propagation of metal corrosion, cation-selective coating decelerated corrosion propagation, and bipolar coating was the most corrosion-resistant among the Four types of phenolic coatings.With the bipolar coating, the anodic current was greatly suppressed, while no current blockage occurred in the cathodic direction.Thus there arose rectiFication of ion movement retarding the ionic current in the anodic direction.The rectiFication phenomenon blocked the Flow of anodic ion transport and led to metal passivation.This showed that the bipolar coating possessed some Function of passivation membrane and had important eFFect on the process of anodic dissolution.国家自然科学基金资助项目;金属腐蚀与防护国家重点实验室课

A Study on AntiCorrosion Performance of IonSelective Phenolic Coatings for Carbon Steel by EIS

研究了涂有不同离子选择性酚醛层的碳钢试样在3%nACl溶液中的电化学交流阻抗谱，用不同的等效电路解析了不同涂层体系的频谱行为，讨论了不同离子选择性涂层对碳钢的防腐蚀性能，分析了各自的耐蚀机理。结果表明，双极性和阳离子选择性酚醛涂层对碳钢的防腐蚀性能比酚醛清漆好，而阴离子选择性酚醛涂层比酚醛清漆差。Abstract The anticorrosion performance of carbon steel painted with anionselective,cationselective and bipolar phenolic coatings,and phenrolic varnish (nonionicselective phenolic coating) as contrast in 3% NaCl solution,was investigated by electrochemical impedance spectroscopy (EIS) technique.The results showed that compared with nonionicselective phenolic coating, the anionselective phenolic coating accelerates the propagation of metal corrosion, whereas cationselective phenolic coating decelerates corrosion propagation, and bipolar phenolic coating is the most corrosionresistance among the fur types of phenolic coatings.国家自然科学基金;中国科学院腐蚀与防护国家重点实验室课

Electron transfer of horseradish peroxidase entrapped in poly-o-phenylenediamine membrane electrode

The poly-o-phenylenediamine membrane electrode containing horseradish peroxidase was prepared by means of the electrochemical immobilization of enzyme, and the voltammetric behavior of the resulting enzyme electrode and its bioelectrocatalysis to hydrogen peroxide reduction was studied. It was found that the direct electron tansfer between the enzyme and the polymer matrix takes place in the biocatalytic processes, For the newly prepared enzyme electrode, however, the oligomers, which are formed during the polymerization of o-phenylenediamine and then incorporated in the enzyme membrane, can play a role of electron transfer mediators to accelerate the regeneration of the oxidized enzyme, From the fitting of experimental current response curves, it can be found that the change in the regeneration rates of the oxidized enzyme with the electrode potentials obeys apparantly the Tafel relationship. The procedure in the measurement of kinetic parameters for enzyme reactions was suggested