Monoethanolamine adsorption on oxide surfaces.

Chemical contaminants are becoming an increasingly greater concern for water quality and it is well known that interactions with geochemical interfaces impact the fate and transport of these contaminants in the environment. In this study, we investigated the interactions of one such chemical contaminant, monoethanolamine (MEA), with oxide surfaces, particularly titanium dioxide (TiO ₂ ) and iron oxide (α-Fe ₂ O ₃ ). Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to probe the adsorption behavior of MEA on titanium dioxide (TiO ₂ ) and iron oxide (α-Fe ₂ O ₃ ) nanoparticles as a function of pH and other environmental conditions including concentration and ionic strength. Both the extent and initial rates of adsorption of MEA on these oxide surfaces increases with increasing pH. Adsorption on these oxide surfaces increases with solution concentration until saturation occurs and MEA adsorbs more readily at higher pH. Furthermore, adsorption decreases with increasing ionic strength, demonstrating the importance of electrostatic interactions to this process. Based on these results, a mechanistic picture emerges for the interaction of MEA with titanium dioxide and iron oxide across a range of pH values. Overall, this study provides important insights into the surface chemistry and interactions between an alkanolamine and geochemical oxide interfaces.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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