盐酸液中溴化十六烷基吡啶对锌的缓蚀作用及吸附热力学性能

为了研究阳离子表面活性剂在盐酸溶液中对锌的吸附及缓蚀作用,用失重法研究了盐酸溶液中溴化十六烷基吡啶对锌的缓蚀作用,并应用吸附理论和Sekine方法对静态挂片试验数据进行处理.结果表明,溴化十六烷基吡啶对锌在盐酸介质中的腐蚀具有良好的抑制作用,是一种吸附型缓蚀剂,低浓度下在锌表面的吸附基本符合Langmuir等温式,相关系数大于0.998.缓蚀率随缓蚀剂浓度增加或温度升高而增大.通过对试验数据的处理,获得了吸附过程△H0、△S0和△G0等重要热力学参数,△H0=14.00 kJ/mol,△S0随温度升高而增加,△G0随温度升高而下降.本研究为后续工作提供了参考.     

盐酸溶液中异喹啉在锌表面的吸附及其缓蚀作用

锌换热设备表面积垢常用盐酸进行清洗,因此研究盐酸介质中锌缓蚀剂有重要意义.采用失重法和电化学方法研究了异喹啉在0.8 mol/L盐酸中对锌的吸附及缓蚀作用、吸附热力学和吸附动力学.结果表明,随异喹啉浓度增大,缓蚀率增大,当浓度增大到1g/L后,缓蚀率达到最大值.随温度升高,吸附系数减小,缓蚀率降低.吸附过程是放热过程,△H0=-30.27 kJ/mol.吸附过程熵值减小,且随温度升高,熵变下降.加入异喹啉后腐蚀电流明显减小,过程活化能由3.29 kJ/mol升高至25.56 kJ/mol.异喹啉明显抑制阴极过程,是一种阴极型缓蚀剂.     

盐酸溶液中肉桂醛对铝的缓蚀作用及吸附热力学研究

本文通过对大量的单组份有机化合物和无机化合物的筛选,选出了肉桂醛这种缓蚀效果较好的化合物作为缓蚀剂,对其进行热力学研究,并分别绘制出不同温度下肉桂醛的吸附等温曲线,肉桂醛在金属铝表面的吸附符合Langmuir吸附规律,分析不同温度下对于肉桂醛缓蚀性能的作用,分别获得了吸附系数、焓变、熵变和自由能变的热力学参数。通过实验得出肉桂醛缓蚀剂的吸附过程是熵值减少的放热过程,随着温度的升高自由能逐渐变大,同时缓蚀率也随之降低。     

土酸溶液中溴化十六烷基吡啶对锌的缓蚀作用及吸附热力学研究

用失重法研究了土酸溶液中溴化十六烷基吡啶对锌的缓蚀作用，发现溴化十六烷基吡啶在锌表面上的吸附是产生缓蚀作用的重要原因，且吸附规律服从Langmuir吸附等温式。用Sekine方法处理实验数据，从而获得了吸附过程△H^0、△S^0和△G^0等一系列重要热力学参数。     

土酸溶液中六次甲基四胺对碳钢的缓蚀作用及吸附热力学研究

采用失重法研究了土酸溶液中六次甲基四胺在不同温度和浓度下对碳钢的缓蚀作用,发现六次甲基四胺能较好地抑制碳钢的腐蚀。六次甲基四胺在碳钢表面上的吸附是产生缓蚀作用的重要原因,且吸附规律服从Langmuir吸附等温式。用Sekine方法处理实验数据,获得了吸附过程相关的重要热力学参数,吸附过程是吸热过程,熵值增大,吉布斯自由能减小;随温度升高,吉布斯自由能变增加,熵变减少,缓蚀率降低。     

氢氧化钠介质中间苯二酚对铝的缓蚀作用及吸附热力学研究

本文采用失重法研究了氢氧化钠溶液中间苯二酚在不同温度和浓度下对铝的缓蚀作用，发现间苯二酚在铝表面上的吸附是产生缓蚀作用的重要原因，且吸附规律服从Langmuir吸附等温式。用Sekine方法处理实验数据，获得了吸附过程相关的重要热力学参数。吸附过程是吸热过程，且熵值增大。随温度升高，吉布斯自由能减少，缓蚀率增大。     

氢氧化钠介质中糠醛对铝的缓蚀作用及吸附热力学研究

本文采用失重法研究了氢氧化钠溶液中糠醛在不同温度和浓度下对铝的缓蚀作用，发现糠醛在铝表面上的吸附是产生缓蚀作用的重要原因，且吸附规律服从Langmuir吸附等温式。用Sekine方法处理实验数据，获得了吸附过程相关的重要热力学参数。吸附过程是吸热过程，且熵值增大。随温度升高，吉布斯自由能减少，缓蚀率增大。     

盐酸溶液中取代吡啶甲酰腙席夫碱缓蚀剂在Q235碳钢表面吸附的热力学和动力学行为

为了全面了解取代吡啶甲酰腙席夫碱在碳钢表面的缓蚀吸附机理,在1mol／L盐酸介质中加入3种水溶性取代吡啶甲酰腙席夫碱缓蚀剂,用Bockirs置换模型研究了缓蚀剂在Q235碳钢表面的吸附热力学规律,得到了吸附热力学参数;用析氢电流衰减曲线法和比色分析法研究了缓蚀剂在Q235碳钢表面吸附的动力学行为。结果表明：3种缓蚀剂的吸附是以化学吸附为主,吸附过程是放热过程,体系温度的升高会对缓蚀剂的吸附起削弱作用;3种缓蚀剂的吸附规律遵从Langmuir吸附模型,其吸附可以自发进行。     

氨基磺酸溶液中肉桂醛对碳钢的缓蚀作用和吸附热力学研究

采用失重法考察不同温度下5％氨基璜酸中,不同浓度的肉桂醛对碳钢的缓蚀作用;并对氨基璜酸介质中肉桂醛在碳钢表面吸附热力学进行了研究。肉桂醛低浓度时,随浓度增大,缓蚀作用增强;当其浓度达到一定值后,缓蚀作用基本保持不变。实验结果表明,肉桂醛在碳钢表面产生单分子层吸附,并且满足Langmuir吸附规律。△G°〈0吸附过程可以自发进行,并且随着温度的升高础增大,吸附作用降低。△H°〈O表明反应是放热过程。△S°〈0表肉桂醛在碳钢表面的吸附过程为熵减少的过程。     

氨基磺酸溶液中溴化十六烷基吡啶对碳钢的缓蚀作用和吸附热力学研究

采用失重法考察了不同温度下5％氨基磺酸中,不同浓度的溴化十六烷基吡啶对碳钢的缓蚀作用;并对氨基磺酸介质中溴化十六烷基吡啶在碳钢表面吸附热力学进行了研究。溴化十六烷基吡啶低浓度时,随浓度增大,缓蚀作用增强;当其浓度达到一定值后,缓蚀作用基本保持不变。实验结果表明,溴化十六烷基吡啶在碳钢表面产生单分子层吸附,并且满足Langmuir吸附规律。△G^0〈0,吸附过程可以自发进行,并且随着温度升高△G^0增大,吸附作用降低。△H^0〈0,表明反应是放热过程。△S^0〈0表示随着缓蚀过程的进行,体系进入更为有序状态。     

Chemical treatment of zinc surface and its corrosion inhibition studies

The surface treatment of zinc and its corrosion inhibition was studied using a product (BTSC) formed in the reaction between benzaldehyde and thiosemicarbozide. The corrosion behaviour of chemically treated zinc surface was investigated in aqueous chloride-sulphate medium using galvanostatic polarization technique. Zinc samples treated in BTSC solution exhibited good corrosion resistance. The measured electrochemical data indicated a basic modification of the cathode reaction during corrosion of treated zinc. The corrosion protection may be explained on the basis of adsorption and formation of BTSC film on zinc surface. The film was binding strongly to the metal surface through nitrogen and sulphur atoms of the product. The formation of film on the zinc surface was established by surface analysis techniques such as scanning electron microscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR).     

Sand sorption process for the removal of sodium dodecyl sulfate (anionic surfactant) from water

Granite sand was used to adsorb anionic surfactant, sodium dodecyl sulfate (SDS) from water at natural pH 6.25. The effect of adsorbent size, pH, temperature and amount of adsorbent has been examined. The results indicate that the Langmuir model provides the best correlation of experimental data. Thermodynamic parameters like entropy, enthalpy and free energy of adsorption were evaluated. Decreasing the temperature accelerates the adsorption of SDS onto sand surface. The kinetic data were analyzed by using pseudo-first order Lagergren equation. Adsorption of SDS was exothermic and dominated by physisorption with activation energy (Ea) 33.65 kJ mol(-1). In addition, regeneration of granite sand by washing with Fenton likes reagent was examined. The results suggested that granite sand is suitable as a sorbent material for recovery and adsorption of SDS from aqueous solutions in view of its effectiveness and cheaper cost.     

线材硫酸盐连续光亮镀锌添加剂的最佳配比及其电化学性能

线材硫酸盐连续镀锌工艺常用于钢丝、钢管等型材的防腐蚀处理,应用广泛,但其镀层晶粒粗糙,光亮度欠佳,存在易变色、耐蚀性能下降等缺点.通过赫尔槽试验,用正交法确定了硫酸盐镀锌液添加剂中主光亮剂苄叉丙酮、载体光亮剂、苯甲酸钠、辅助光亮剂A和扩散剂NNO的最佳配比以及最大影响因子,研究了各组分的电化学性能.结果表明:组合添加剂组成的最佳配比为2:22:8:1:6,对镀层影响最大的因子是主光亮剂 载体以及辅助光亮剂A的量,其他组分与主光亮剂、载体及辅助光亮剂A产生协同效应,也能有效地提高镀液和镀层的综合性能.优化该添加剂的复配对减低生产成本具有一定的指导作用.     

Seed Extract of Psidium guajava as Ecofriendly Corrosion Inhibitor for Carbon Steel in Hydrochloric Acid Medium

The anticorrosion characteristics of the seeds of Psidium guajava (P. guajava) fruits on carbon steel in acid medium were examined with weight loss data and subsequently thermodynamic factors such as heat of adsorption of the inhibitor on the metal surface (Q), change in entropy (△S), change in free energy of the reaction (△G), corrosion rate (CR) and energy of activation for corrosion reaction of carbon steel (E) were also evaluated. Adsorption isotherm was plotted to study the adsorption of the inhibitor on the metal surface with increasing concentration of the inhibitor. The functional groups responsible for inhibition were investigated using Fourier transform infrared (FT-IR) spectra. Electrochemical parameters were evaluated through the potentiodynamic Tafel polarization and impedance spectral studies. Scanning electron microscopy (SEM) micrographs were recorded to investigate the change in surface morphology. The complete study reveals the e?ciency of seed extract of P. guajava as a safe, ecofriendly and alternate corrosion inhibitor for carbon steel in acid medium.     

Low-temperature synthesis of ZnO nanorods using organic-inorganic composite as a seed layer

Well-aligned zinc oxide (ZnO) nanorods were synthesized using a low-temperature hydrothermal method employing a zinc/sodium dodecyl sulfate (Zn/SDS) composite as a seed layer. The results of X-ray diffraction measurements indicate that the Zn/SDS composite has a lamellar structure with an interlayer distance of 3.12 nm, which is shorter than that of the lamellar structure of SDS (3.82 nm) due to ion exchange between Zn and Na. The results of X-ray absorption fine structure analyses suggest that ZnO crystals start to grow after an induction period of 20-30 min. The length of nanorods and the aspect ratio of ZnO nanorods could be controlled by altering the molarity of ammonium and zinc nitrate in the growth solutions.     

Effect of triethanolamine and sodium dodecyl sulfate on the formation of CuInSe2 thin films by electrodeposition

In this paper, we describe the development of a bath comprising triethanolamine and sodium dodecyl sulfate for electrodeposition of CuInSe₂ thin films, by which long-term bath stability was found to be improved and near-stoichiometric CuInSe₂ films with smooth surface morphology were obtained. Scanning electron microscopy studies reveal a dramatic improvement of the crystalline quality of CuInSe₂ films with the addition of sodium dodecyl sulfate. X-ray diffraction results and Raman spectra confirm that the improvement of the film growth is attributed to the synergistic effect of triethanolamine and sodium dodecyl sulfate. The addition of anionic surfactant sodium dodecyl sulfate can significantly improve the adherence between the CuInSe₂ layer and the substrate.     

20碳钢水基清洗剂的配制及应用效果

为了洗净量大面广的钢铁制品表面的防锈油,配制了一种有效的20碳钢水基清洗剂。采用单因素试验法,逐一对5种市售非离子表面活性剂进行了除油清洗,优选出表面活性剂(脂肪醇聚氧乙烯醚)后,确定PAA分散剂、助剂和缓蚀剂的最佳含量。按照国标分别采用DDS-307A电导仪、722N可见分光光度计测定清洗剂的临界胶束浓度和浊点。结果表明:20碳钢水基清洗剂的最佳组成为4 g/L 087型表面活性剂,3 g/L 731分散剂,12 g/L无水碳酸钠,4 g/L硅酸钠,1~2 g/L十二烷基硫酸钠。本清洗剂碱度小、耐酸性好、除油效果能满足生产需要。     

曼尼希碱/钨酸钠复配对N80钢缓蚀的协同作用

采用电化学方法和扫描电镜研究曼尼希碱与钨酸钠在盐酸溶液中对N80钢的缓蚀作用,探讨其在N80钢表面的吸附行为,并且从腐蚀热力学和动力学角度分析复合缓蚀剂分子的缓蚀机理。结果表明:曼尼希碱加入盐酸溶液中后,增大了电荷转移电阻,降低了金属表面的腐蚀速率;它与钨酸钠复配后,金属表面的饱和吸附量增加,N80钢在盐酸溶液中的抗腐蚀性能显著增加,表现出了良好的协同效应。当曼尼希碱和钨酸钠摩尔比为1∶1.5时,缓蚀效率可达99.65%。该缓蚀剂在N80钢表面的吸附服从Langmuir吸附模型,属于以化学吸附为主的吸附,且此过程为吸热反应。     

席夫碱基聚乙二醇(400)月桂酸酯表面活性剂在碱性锌电池中的缓蚀性能

为了研发一种能应用于碱性锌电池的代汞缓蚀添加剂,以解决锌电极易变形、长枝晶等问题,合成了3种席夫碱基聚乙二醇(400)月桂酸酯表面活性剂(M1、M2、M3),通过失重法、电化学技术、表面分析等方法研究了其在6 mol/L KOH电解液(饱和Zn O)中对锌电极的缓蚀效果。结果表明:缓蚀率随席夫碱基表面活性剂浓度升高而增加,室温下3种席夫碱基表面活性剂中M3缓蚀能力最强,缓蚀率最高达92.14%,缓蚀能力大小为M3M2M1,属于抑制阴极型缓蚀剂;表面分析揭示3种席夫碱基表面活性剂在锌电极表面上形成吸附层,其吸附符合Langmuir等温吸附模型,吸附平衡常数较大,M1、M2、M3的Kads分别为5 875.441,18 750.012,187 500.117 L/mol,适合作为碱性锌电池的缓蚀添加剂。     

Temperature dependence of the effect of liquid metals on the long-time strength of solid metals

This article describes long-time strength tests carried out at various temperatures on copper in liquid bismuth, a nickel alloy in sodium, and armco iron in zinc. It is shown that experimental data is in good agreement with theoretical concepts about the effect of adsorption, corrosion and diffusion of liquid metals on the properties of solids.