Adsorption Kinetics of Benzothiazole and 2-Mercaptobenzothiazole on Microcrystalline Gold and Silver Surfaces

Abstract:

Adsorption kinetics of benzothiazole (BNS) and mercaptobenzothiazole (2-MBT) (1×10^-1M, 1×10^-2M and 1×10^-3M) were studied during 5000 s on gold and silver coated At-cut quartz microelectrodes, using EQCM. The frequency change fits well to the Langmuir isotherm in the case of 2-MBT, while BNS presents adsorption-desorption periods making the fitting non realiable. The calculated ΔG_ads of 2-MBT corresponds to physisorption Ag (-1.38 kcal mol^-1) and Au (-1.94 kcal mol^-1). On both metal surfaces (Au and Ag) the amount of adsorbed mass for 2-MBT is significantly larger (20.76 μg cm^-2 and 6.03 μg cm^-2) than on BNS (0.33 μg cm^-2 and 0.88 μg cm^-2). These facts could be explained by the deprotonation of 2-MBT giving place to an anion, which is prone to interact with both positively charged surfaces of Au and Ag. However, BNS protonates giving place to a cation and making more difficult its adsorption on both metals.

• Periodical: Solid State Phenomena (Volume 227)
• Pages: 99-102
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.227.99
• Online since: January 2015
• Authors: Jorge Ramírez Cano, Lucien Veleva*
• Keywords: 2-Mercaptobenzothiazole, Adsorption Kinetics, Benzothiazole, EQCM, Inhibitor, Langmuir Adsorption, Microcrystalline Gold, Microcrystalline Silver

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