- Tytuł:
- Adsorption of sodium/calcium poly(acrylic acid) salts on anatase: effect of the polyelectrolyte molecular weight and neutralization
- Autorzy:
- Jacquemet, Christian
- Powiązania:
- https://bibliotekanauki.pl/articles/1449765.pdf
- Data publikacji:
- 2020
- Wydawca:
- Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
- Tematy:
-
adsorption
free energy
Langmuir isotherm
sodium-calcium poly(acrylic acid) salts
anatase - Opis:
- Abstract: Interactions of poly(acrylic acid)s (PAAs) of two different molecular weights (Mw = 9,560 g×$mol^{-1}$ and 4,220 g×$mol^{-1}$) with surfaces of an untreated anatase $TiO_2$ were assessed through adsorption isotherm measurements. Those dispersants were tested under different sodium-calcium neutralization states (molar ratio $r = Ca^{2+}$ / $CO_{2-}$ varying from 0 to 0.35). Their behavior towards the $TiO_2$ surfaces can be described by the Langmuir adsorption model. For both polymers, surface coverage ($Γ_max$) evolves linearly with the molar ratio $r$. For a given r value, a lower surface coverage was observed with the polymer having the highest molecular weight. The free energy of adsorption ($/DeltaG_{ads}$) of PAAs was estimated from adsorption experiment data. This calculation indicates that sorption occurs spontaneously and is unlikely to be of chemical nature. The absolute values of $/DeltaG_{ads}$ are higher for the highest molecular weight polymers suggesting that they are more strongly adsorbed to anatase surfaces. The absolute values of $/DeltaG_{ads}$ per mole of sodium-calcium macromolecules are found to be lower than those calculated for their homologues 100% sodium neutralized suggesting that they are bound with the solid by a fewer number of segments.
- Źródło:
-
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 113-123
1643-1049
2084-4735 - Pojawia się w:
- Physicochemical Problems of Mineral Processing
- Dostawca treści:
- Biblioteka Nauki
Artykuł