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首页> 外文期刊>International Journal of Electrochemical Science >Adsorption of an Azo Dye on Polyaniline/ Niobium Substrate
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Adsorption of an Azo Dye on Polyaniline/ Niobium Substrate

机译：偶氮染料在聚苯胺/铌基质上的吸附

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In this paper the adsorption process of an azo dye on nanostructured polyaniline films electrodepositedon niobium has been investigated using electrochemical impedance spectroscopy. The electrochemicalpolymerization has been carried such as to obtain PANI films with a highly branched structure and ahigh specific surface. Based on the impedance results it has been observed that dye concentrationaffects the adsorption mechanism. The surface adsorption influences the overall mechanism and itcould take place simultaneously with the intraparticle diffusion. The relaxation time could estimate theapproach of the system to steady state (equilibrium). In diluted dye solution the relaxation time ishigher and the intraparticle diffusion could play an important role. Five adsorption isotherms havebeen used for the mathematical description of adsorption equilibrium data. All the isotherms describewell the adsorption phenomena except Frumkin isotherm. In our case the Langmuir model gave a-5 -1 better fit for concentrated dye solution (> 310 mol L ) and diffused control Langmuir model for-5 -1 diluted dye solution (< 210 mol L ). The high correlation coefficient and low standard deviationvalue gave the best fit for Langmuir isotherm. The change of Gibbs energy has been also evaluated for -1 the adsorption of dye onto polyanilineiobium substrate. The negative ads value (-36.38 kJ mol )-1 and high value of Kads (33705.67 mol ) obtained in our measurements indicate that adsorption processis spontaneous and a stable adsorbed dye layer on the polyaniline surface is formed. The adsorptiontakes place via a combination of physical and chemical adsorption but mainly due to physicaladsorption.
机译：本文利用电化学阻抗谱研究了偶氮染料在电沉积在铌上的纳米结构聚苯胺薄膜上的吸附过程。已经进行了电化学聚合，以便获得具有高度支化结构和高比表面的PANI膜。基于阻抗结果，已经观察到染料浓度影响吸附机理。表面吸附影响整体机理，并且可以与颗粒内扩散同时发生。弛豫时间可以估计系统达到稳态（平衡）的方式。在稀释的染料溶液中，弛豫时间更长，颗粒内扩散可能起重要作用。五个吸附等温线已用于吸附平衡数据的数学描述。除Frumkin等温线外，所有等温线都很好地描述了吸附现象。在我们的案例中，Langmuir模型使浓染料溶液（> 310 mol L）的a-5 -1更好，而-5 -1稀释染料溶液（<210 mol L）的扩散控制Langmuir模型更适合。高相关系数和低标准偏差值最适合Langmuir等温线。还评估了吉布斯能量的变化对染料在聚苯胺/铌基质上的吸附-1的影响。在我们的测量中获得的负广告值（-36.38 kJ mol）-1和高值的Kads（33705.67 mol）表明吸附过程是自发的，并且在聚苯胺表面上形成了稳定的吸附染料层。吸附是通过物理吸附和化学吸附的结合进行的，但主要是由于物理吸附。

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