Attenuated Total Reflection Fourier Transform Infrared Spectroscopic Investigation of the Solid/Aqueous Interface of Low Surface Area, Water-Soluble Solids in High Ionic Strength, Highly Alkaline, Aqueous Media

Abstract

A new method for the investigation of the adsorption of the series of surface active quaternary ammonium (QA) compounds, dodecyltrimethylammonium bromide (C12), tetradecyltrimethylammonium bromide (C14), and hexadecyltrimethylammonium bromide (C16) on the surface of sodium oxalatesa Bayer process solidshas been developed using Fourier transform infrared (FTIR) attenuated total reflection (ATR) spectroscopy. The technique involves the use of a finely ground sodium oxalate combined with an appropriate adsorption matrix and, for the first time, permits the in situ investigation of adsorption from high ionic strength, highly alkaline (pH 12), aqueous media onto a water soluble, low surface area solid: sodium oxalate (a compound traditionally treated as ligand or adsorbate). Spectroscopic results show the formation of surfactant aggregate clusters on the surface of sodium oxalate and suggest adsorption in the order C16 > C14 > C12. This new method will allow the acquisition of "dose-response" curves for the C12, C14, and C16 QAs on sodium oxalate (under the aforementioned conditions), while also leading to the in situ investigation of the surface of sodium oxalate in synthetic and process Bayer liquors (high ionic strength, extremely alkaline media). Our results suggest that this method will be well suited to interfacial research in other similar areas involving complex, nonideal industrial systems which also depend upon chemical processes occurring at the solid/aqueous and solid/liquid interfaces.

Time dependence of nucleation and growth of silver nanoparticles generated by sugar reduction in micellar media

“…The appearance of the peaks at 2835 cm À1 (symmetric-CH 2 -stretching), 2903 cm À1 (antisymmetric-CH 2 -stretching), 1444 and 1361 cm À1 (methylene scissoring), 1154 cm À1 (antisymmetric-SO 3 -stretching), 1038 cm À1 (symmetric-SO 3 -stretching) and 793 cm À1 (rocking (CH 2 ) n ) indicate the attachment of the SDS molecules to the surface of the silver nanoparticles. Moreover, the corresponding shifts in these peaks in comparison to the pure surfactant (Table 2) are attributed to the constraint capping molecular motion, which resulted from the formation of relatively close packed surfactant monolayer on the silver nanoparticles surface [47].…”

A review of the determination of organic compounds in Bayer process liquors

“…Fourier transform infrared (FTIR) spectroscopy has been used by Wilson Hind et al [88,89] used FTIR spectroscopy to investigate the nature of the surfaces of 665 solids in contact with highly alkaline solutions.…”

In situ AFM investigation of heterogeneous nucleation and growth of sodium oxalate on industrial gibbsite surfaces in concentrated alkaline solution

“…The reason for using this synthetic liquor to replace industrial Bayer liquor in this study is that the glass window of AFM cantilever holder cannot resist highly caustic solution. The similar methodology has been applied to the investigation of the adsorption of quaternary ammonium compounds on solid sodium oxalate and gibbsite in synthetic liquor using FTIR-ATR spectroscopy (Hind et al, 1997).…”