An In Situ Infrared Spectroscopic Study of the Adsorption of Lysine to TiO₂ from an Aqueous Solution

Abstract

The first in situ internal reflection infrared spectroscopic study of lysine adsorption from an aqueous solution to TiO2 films is reported. The infrared spectrum of lysine adsorbed to TiO2 from an aqueous solution at an intermediate pH of ∼5−7 strongly resembles that of solution lysine, indicating that lysine is electrostatically adsorbed. At this pH, favorable electrostatic interactions occur between the lysine cation and the negatively charged TiO2 film (point of zero charge at pH ∼5). A Langmuir isotherm analysis was used to obtain an equilibrium constant for lysine adsorption at pH 7.4 of 3 × 103 M-1, consistent with an electrostatically adsorbed surface species. Increasing the crystallinity of the TiO2 film did not affect lysine adsorption. The surface titration by internal reflection spectroscopy (STIRS) technique has been used to investigate the effect of pH change on lysine adsorption to TiO2. Maximum lysine adsorption to TiO2 occurs near the lysine isoelectric point of 9.8.

Soil Chemical Insights Provided through Vibrational Spectroscopy

“…Substantial progress has been made in understanding bacterial adhesion processes through the use of model compounds. For example, elucidation of carboxylate binding mechanisms has been facilitated through FTIR experiments examining amino acids (Norén et al, 2008;Parikh et al, 2011;Roddick-Lanzilotta et al, 1998;Roddick-Lanzilotta and McQuillan, 2000) and model carboxylic acids (Boily et al, 2000;Deacon and Phillips, 1980;Ha et al, 2008;Norén and Persson, 2007). In fact, studies by Alcock and coauthors (1976) and later refined by others (Chu et al, 2004;Deacon and Phillips, 1980;Dobson and McQuillan, 1999), demonstrate that carboxyl binding mechanisms can be inferred through the separation differences (Δν) between the asymmetric carboxylate [ν as (COO − Following the spectral interpretations for model carboxylate compounds, there is evidence for carboxyl involvement during adhesion of P. putida to hematite (α-Fe 2 O 3 ) under flow conditions, possibly forming bidentate bridging complexes to the mineral surface [ν s (COO − ) shift from 1400 to 1415 cm −1 ; Δν ≈ 150 cm −1 ], with additional binding interactions through polysaccharides and phosphoryl groups (Ojeda et al, 2008).…”

Mineral Surfaces, Geochemical Complexities, and the Origins of Life

“…Dozens of recent studies reveal complexity in structure and speciation of adsorbed organics, particularly through in situ FTIR and other spectroscopic studies (Somasundaran and Krishnakumar 1994;Rodriguez et al 1996;Holmen et al 1997;Roddick-Lanzilotta et al 1998;Fitts et al 1999;Klug and Forsling 1999;Kubicki et al 1999;McQuillan 1999, 2000;Duckworth and Martin 2001;Sheals et al 2002;Lackovic et al 2003;Rosenqvist et al 2003;Yoon et al 2004Yoon et al , 2005Johnson et al 2004aJohnson et al , 2004bJohnson et al , 2004cJohnson et al , 2005aJohnson et al , 2005b (Thomas et al 1993;Orme et al 2001;Asthagiri and Hazen 2007). In addition, for the calcite-water interface, many theoretical simulations and observations exist to guide surface chemical models (Stipp and Hochella 1991;Parker 1997, 1999;Teng et al 1998Teng et al , 2000Fenter et al 2000;Wright et al 2001;Stipp 2002;de Leeuw and Cooper 2004;Geissbuhler et al 2004;Kristensen et al 2004).…”

Surface Properties of a Nano-Quasicrystalline Forming Ti Based System

“…26) Attributions of IR bands have been carefully checked consistently with several spectroscopy data basis. 26,48) Figure 8 reports spectra of species adsorbed to the three different substrates mentioned previously from a 10 À1 molÁdm À3 aqueous Lglutamic acid solution. The wavenumbers of the prominent bands are presented in Table 4.…”