Influence of solution pH on stability of aluminum oxide suspension in presence of polyacrylic acid

Abstract

The effect of solution pH and molecular weight of polyacrylic acid (PAA) on its adsorption as well as on stabilization-floculation properties of the colloidal Al 2 O 3 and electrolyte solution systems was studied.The measurements showed that at pH = 6, the presence of the polymer of molecular weight 2 000 and 240 000 does not change stability of Al 2 O 3 suspension. However at pH = 3 and 9 the effect of polyacrylic acid is significant. At pH = 3 it creates destabilization of the suspension while at pH = 9 PAA it improves significantly the stability of Al 2 O 3 .It was shown that the increase in solution pH affects conformation of adsorbed macromolecules which causes the decrease in PAA adsorbed amount and thickness of polymer adsorption layer.By comparing the values of diffusion layer and surface charges, main effects responsible for the decrease in surface charge and ζ potential of the solid in the presence of the polymer as well as suspension stability were determined.

The Catalytic Impact of Ethionine on the Multi-Step Electroreduction of Bi(III) Ions in Chlorates(VII) Solutions

“…With an increase in the concentration of ethionine, the peak does not change its position significantly, but its height increases. The surface tension values (Table 2) at potential of zero charge γ z decrease, which also confirms the phenomenon of ethionine adsorption [21][22][23][24][25] on the electrode. Therefore, it can be stipulated that active Bi(III)-ethionine complexes are certainly located inside the adsorptive layer (Fig.…”

Impact of poly(vinyl alcohol) adsorption on the surface characteristics of mixed oxide Mn x O y –SiO2

“…In such a case, solid surface modification is necessary. Of great variety of techniques; plasma modification (Kuraica et al 2003;Punga and Borcia 2013), adsorption of different low-and high-molecular compounds (Chibowski et al 2010;Nosal-Wiercińska 2012, 2013Wiśniewska et al 2013a;Nosal-Wiercińska 2014) and synthesis of mixed oxides (Maliyekkal et al 2006;Wu et al 2010) acquired the most significant importance. Appropriate modification leads to obtaining solids of the properties desired in various ecological and technological processes (Kaźmierczak et al 2013;Nowicki et al 2014Nowicki et al , 2015a.…”

Adsorption and elektrokinetic properties of the system: carboxymethylcellulose/manganese oxide/surfactant

“…This fact can be explained by the presence of the negatively charged groups from the CMC and SDS molecules or from the polysaccharide/surfactant complexes: CMC/ SDS, CMC/polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether, CMC/SDS/polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether. These negative groups are not linked with the surface but present in the compact part of the electric double layer (Chibowski et al 2004(Chibowski et al , 2010. Another observation is that there is no significant difference between the surface charge density of MnO 2 in the presence of different surfactants.…”