Surface acid–base properties and hydration/dehydration mechanisms of aluminum (hydr)oxides

Uranyl and arsenate cosorption on aluminum oxide surface

“…The pH of the aged suspension was 4.5-5.5. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) showed that the c-Al 2 O 3 surface slowly transforms to a layer of a-Al(OH) 3 (gibbsite) and b-Al(OH) 3 (bayerite) mixture upon hydration, in agreement with previous studies (e.g., Wijnja and Schulthess, 1999;Arai et al, 2001;Paglia et al, 2006;Roelofs and Vogelsberger, 2006;Yang et al, 2007).…”

Modelling of the adsorption of phenolic acids onto α,γ–alumina particles

“…For the three ionic strengths, the optimized C values do not satisfy condition (9) (see Fig. 3), but they are of the same order of magnitude or lower than those used by other authors in low ionic strength conditions [35,[66][67][68][69]72]. As shown in Table 3, int K 1 , int K 2 and N s do not vary with ionic strength.…”

“…Dissolution of aluminum oxo-hydroxides are low in the neutral pH region whereas it is higher for pH below 5 or above 8 [11,13,47,69]. Fig.…”

“…Due to the large linear part of the titration results, the fitting with DLM cannot converge. As some authors used this model at ionic strengths lower than 0.1 mol L −1 [35,[67][68][69], Lützenkirchen [50] stressed that some precautions must be taken so that this model makes sense under low ionic strength conditions. First, the relationship between the oxide charge (or sorbed H + ) and pH must be linear, which is verified in this work for our values of ionic strength, as shown in Fig.…”

In situ magnetic resonance imaging study of the impregnation of γ-alumina pellets

“…Highly active catalysts were obtained by modifying the sulfidation procedure [11], using carriers other than alumina [12][13][14], employing various precursors, such as thiometallates [15], carbonyl complexes [16], heteropolyanions [17] or even additives such as chelating agents [18,19]. Furthermore, the physicochemical properties of the ␥-alumina support itself were studied [20], as well as those of the active species during the impregnation process [21][22][23].…”