Fourier transform Raman spectra of methyl red adsorbed on untreated and pretreated γ-alumina and silicaalumina calcined at 900 o C under 1 atm steam flowing were recorded. Spectral analysis shows that the active species adsorbed on γ-alumina was to be deprotonated methyl red, and on silica-alumina to be di-protonated. This indicates that γ-alumina adapted in this work holds Brönsted basicity, and silica-alumina Brönsted acidity. Raman intensities of methyl red on pretreated γ-alumina are about three times stronger than on untreated γ-alumina, while spectral features are unchanged. For silica-alumina, spectral features show modified vibrational characteristics upon surface hydroxylations generated from pretreatment. Consequently, the acidity loss for silica-alumina and the basicity gain for γ-alumina were observed by increasing the surface hydroxyl groups on the catalysts through pretreatment of the steam calcination.

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A simple cyclic voltammetry (CV) analytical method with organo-modified sericite for the working electrode was investigated to detect As(III) in an aquatic environment, and optimal conditions for the reliable measurement of trace amounts of As(III) were studied. A distinct, specific peak was clearly observed at 0.8 V due to the reduction of H3AsO4 to H3AsO3. The specific peak current of arsenic increased with increasing the concentration of As(III) and initially increased proportionally to the scan rates. However, it disappeared as the scan rate increased over 400 mV/s. Because the surface of the organo-modified sericite electrode rapidly became saturated with As(III) when the deposition time increased, an optimal deposition time was determined as 60 s. Pb(2+) had no significant influence on the peak signal of As(III), whereas it was reduced as the ratio of Cu/As increased. Considering the detection limit of arsenic (1 ppb), this system can be used to detect low levels of As(III) in water systems.

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Li+ ion complex of azacrown ether with restricted motion of freedom and pseudo-bilateral symmetry was studied by infrared spectroscopy, which has shown simplified and broadened vibrational features. The C=O and N-H stretching bands, in particular, shows anomalous broadening nearly ~150 cm -1. The density functional calculation at the level of BP86/6-31+G** shows that Li + ion is trapped and rather free to move around inside the cavity, as much as about 0.70 Å. Through the relocation of Li + ion inside the cavity, the conformational changes would occur rapidly in its symmetry C1 ⇄ C2 ⇄ C1. The potential barrier was obtained to be merely ~2.2 kJ/mol for C1 → C2. During this conformational alteration, the amide backbone twists concurrently its dihedral angle side to side about up to ±3 degree. Selected vibrational modes were interpreted in terms of the force constant variations of local symmetry coordinates between conformations in the framework of C1 ⇄ C2 ⇄ C1.