The Adsorption Stability of Interface Corrosion Inhibitor

研究表明：在一定条件下，阳极脱附电位可作为评价缓蚀剂吸附稳定性的一个经验参数；缓蚀剂吸脱附诱导的电化学振荡是缓蚀体系的一种特殊失稳状态，即缓蚀剂吸附过程与电极反应中间吸附态产物耦合的结果；卤素离子的协同作用不仅可以提高某些有机缓蚀剂的吸附复盖度，而且可以增强其吸附稳定性；微分极化曲线是研究吸附稳定性的有效方法Some new results on the adsorption stability of interface corrosion inhibitor are presented. The concept of adsorption stability and the factors influencing the adsorption stability were discussed. It is shown that the anodic desorption potential can be employed to evaluate the adsorption stability of the inhibitor as an empirical character in some conditions. Electrochemical oscillations phenomena were observed for the first time on a rotating iron electrode in H2SO4 solution containing organic inhibitor in the active potential region. These potentiostatic current oscillations can occur under cathodic polarization, as well as under anodic plarization. The oscillation period, amplitude, incubation time and waveform changed with the applied potential and electrode rotating speed. The oscillations sustained even with strong stirring, but were inhibited by the codsorption of organic molecules and halides. This periodic behavior of oscillation may be attributed to the cycle between the partial desorptioon the iron surface. The synergistic effect of organic molecules and halides ions may enhance the adsorption stability of the inhibitor on the metal surface. A differential polarization curve method was proposed to study the adsorption stability and anodic desorption behaviors of the inhibitor.作者联系地址：武汉大学环境科学系Author's Address: Dept. of Environmental Sci., Wuhan Univ., Wuhan43007

The Adsorption desorption Behaviors of β phenylaminopropiophenone on iron in sulphuric acid solution

用极化曲线法研究了０．５ｍｏｌ·Ｌ－１硫酸溶液中β－苯胺基苯丙酮（ＰＡＰ）在铁－溶液界面的吸脱附行为及Ｃｌ－，Ｉ－的影响．结果表明，ＰＡＰ的吸附遵循Ｆｌｏｒｙ－Ｈｕｇｇｎｓ等温式；在较正的极化电位区出现阳极脱附现象．讨论了两种粒子联合吸附方式与浓度的关系，提出可根据吸附粒子的脱附电位与其浓度关系来推断联合吸附的理论模型The adsorption desorption behaviors of β phenylaminopropiophenone (PAP) on iron in 0.5 mol·L -1 H 2SO 4 solution with or without halide ions (Cl -,I -) were investigated by potentiostatic polarization measurement. The results show that the adsorption of PAP on iron surface follows Flory Huggins isotherm, the adsorption free energy parameter ( f ) is positive in H 2SO 4 solution; In the presence of 0.1 mol·L -1 Cl -1 , when C PAP ≤2×10 -5 mol·L -1 , f0 . A desorption phenomenon was observed at more positive potential region in anodic polarization curves. Furthermore, the anodic desorption potential ( E des ) of PAP+X - is independent of PAP concentration at lower concentration region, and E des vs. lg C PAP is a straight line at higher concentration region. The joint adsorption modes under different conditions were determined according to the above stated relation of E des to PAP concentrations as well as the adsorption free energy parameter f values.作者联系地址：武汉大学环境科学系Author's Address: Department of Environmental science, Wuhan University, Wuhan 43007

A Study of Adsorption Kinetics of β-phenylaminopropiophenone on Iron in Acid Solution

用计时电流法研究了０．５ｍｏｌ／ＬＨ２ＳＯ４溶液中β－苯胺基苯丙酮（ＰＡＰ）、卤素离子（Ｃｌ－，Ｉ－）在铁电极上的吸附动力学行为以及Ｃｌ－对ＰＡＰ吸、脱附速度的影响，求得了吸、脱附速度常数ｋａ、ｋｄ和吸附自由能参数ｆ值．结果表明，当ＰＡＰ发生化学吸附时，ｋａ比ｋｄ约大２个数量级，吸附粒子间存在吸引力．在电极表面已吸附有Ｃｌ－的条件下，且当ＰＡＰ浓度较低时发生静电吸附，ｋａ比ｋｄ约大４个数量级，吸附粒子间存在排斥力；浓度高时则发生化学吸附．The adsorption kinetics of β-phenylaminopropiophenone (PAP) on iron electrode in 0.5 mol/L H_2SO_4 solution with or without Cl~- were investigated by chronoamperometry. According to the following adsorption kinetic equation dθ/dt=kaCen-1(1-θ)nexp(fθ/2)-kdθexp(-fθ/2)The rate constants ka, kd as well as the adsorption free energy parameter f of PAP in sulfuric acid soltuion was calculated by used a computerized curve fitting program, the calculated ka, kd are in the order of 10~-1 mol/L s~-1 and 10~-3 s-1, respectively, f>0 in the concentration region of 5×10~-5 to 1×10~-3 mol/L of PAP. While in the 0.5 mol/L H_2SO_4 solution with 0.1 mol/L Cl-,the values of ka, kd are 66 mol/L s~-1 and 1.8×10~-3 s-1, respectively, f0 when CPAP=1×10~-3 mol/L. Otherwhere, authors proved that the PAP occurred electrostatic adsorption under former condition, and it is chemisorbed on the iron surface under latter condition.作者联系地址：武汉大学环境科学系Author's Address: Dept. of Envir. Sci., Wuhan Univ., Wuhan 43007

Studies of the Electrode Preparation of Electrode from Lead Carbonate for Lead acid Battery Ⅰ The activation of the PME

用循环伏安法研究了ＰｂＣＯ３ 粉末微电极转化为ＰｂＳＯ４ 电极的活化方法和条件．发现在２ ～２－５ ｍｏｌ／ＬＨ２ＳＯ４ 溶液中由ＰｂＣＯ３ 转化成ＰｂＯ２／ＰｂＳＯ４ 和ＰｂＳＯ４／Ｐｂ 电极时，以不对称交变讯号活化（ 化成） 后，其循环伏安性能与由球磨机生产的ＰｂＯ 粉所制得的相应电极性能相近．对于负极，在含有乙炔黑胶体的Ｈ２ＳＯ４ 溶液中化成，由于碳胶粒在ＰｂＳＯ４ 晶体上的吸附，阻止了充放电过程中电极材料的收缩，同时增加了电极的导电性，从而促进活性物质的转化形成Lead carbonate which was an intermediate product in lead hydrometallurgy without pollution of lead vapor and sulfur dioxide was selected as electrode material of lead_acid batteries. In the present work,the performances of PbO 2/PbSO 4 or PbSO 4/Pb electrode transformed from PbCO 3 have been investigated by powder microelectrode technique combined with cyclic voltammetry.The results show that the CV characteristics of either negative or positive electrode prepared from PbCO 3 is as good as that of both electrodes made from lead oxide produced by mill machine,when a powder microelectrode with PbCO 3 transformed into PbSO 4 in 1.0 mol/L H 2SO 4 solution,and then activated to form Pb or PbO 2 using an unsymmetrical interchangeable signal( Q a/ Q c or Q c/ Q a being 0.2～0.4) in 2.0～2.5 mol/L H 2SO 4 solution.Furthermore,comparing the negative electrode activated in 2.5 mol/L H 2SO 4 solution containing 4% carbon colloid with one activated in the same H 2SO 4 solution concentration without ABC,the cyclic voltammetric characteristics of the former has been obviously improved.It is possible that the carbon colloid particles can be adsorbed on PbSO 4 crystals,which could increase the conductivity and reduce the shrinking of the electrode作者联系地址：武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072Author's Address: Dept.of Chem.,Wuhan Univ.,Wuhan 43007

Studies of the Preparation of Electrodes from Lead Carbonate for Lead-acid Battery Ⅱ.The Preparation of Paste Electrodes

由PbCO3 、添加剂和硫酸溶液分别混合成正、负极膏 ,制成涂膏式铅酸蓄电池电极 .研究了不同化成方法和充放电条件对电极放电容量和活性物质利用率的影响 .结果表明 ,正极以 2 .0mA/cm2 化成后 ,在同一电流密度下充放电时 ,其性能优于较高电流密度化成的电极 ,活性物质利用率达 74.4% ;以不对称方波电流化成的负极 ,其活性明显高于恒电流化成负极的活性 .这种电极在 2 .0mA/cm2 放电条件下 ,活性物质利用率达 90 %以上 .文中还讨论了由上述正负极组成的简单模拟电池的放电行为 .The positive and negative pastes were prepared by mixing PbCO 3 and H 2SO 4 solution as well as relative additives, respectively. The effects of the various formation methods and the charge/discharge conditions on discharge capacity and active material utilization of both electrodes were examined. The results indicate that the performance of the positive electrode formed at 2.0 mA/cm 2 is better than that formed at higher current density under the same charge/discharge condition, the PAM utilization reaches 74.4 % under discharging at 2.0 mA/cm 2; and the property of the negative electrode formed by unsymmetrical square wave is superior to that formed by constant current when using the same density, the AM utilization of the former is more than 90 % under discharging at 2.0 mA/cm 2. Moreover, the discharge behavior of a lead/acid battery composed of the above positive and negative electrodes was discussed.作者联系地址：武汉大学化学与环境科学学院!湖北武汉430072,武汉大学化学与环境科学学院!湖北武汉430072,武汉大学化学与环境科学学院!湖北武汉430072,武汉大学化学与环境科学学院!湖北武汉430072,武汉大学化学与环境科学学院!湖北武汉430072Author's Address: Dept. of Chem.,Faculty of Chem. and Environmental Science, Wuhan Univ., Wuhan 430072, China$$