Surface forces arising from adsorbed hydrolysis products of metal ions in ZrO2 and silica dispersions: Cu(II), Ni(II), Co(II) and Al(III)

Leong, YeeKwong (2007) Surface forces arising from adsorbed hydrolysis products of metal ions in ZrO2 and silica dispersions: Cu(II), Ni(II), Co(II) and Al(III). Powder Technology, 179 (1-2). pp. 38-42.

[img] PDF
Restricted to Repository staff only

View at Publisher Website: http://dx.doi.org/10.1016/j.powtec.2006....
 
11
4


Abstract

The effects of hydrolyzable Cu2+, Co2+, Ni2+and Al3+ ions on the zeta potential and yield stress behaviour of ZrO2 and SiO2 dispersions were evaluated as a function of pH. With ZrO2 dispersion, adsorbed hydrolysis product of Cu2+ increases the yield stress at zero zeta potential while that of Al(III) decreases it. As the particles are completely coated with hydrolysis product, the most probable explanation for the stronger attraction between ZrO2 particles coated with Cu2+ hydrolysis products must be due to an increase the effective Hamaker constant of particle in water. In the case of ZrO2 particles coated with Al3+ hydrolysis products, the effective Hamaker constant is decreased. Silica dispersions are not flocculated even at its point of zero charge of pH ~2.0. However this dispersion is flocculated by the adsorbed hydrolysis products of Co2+ and Ni2+ ions. The onset of flocculation corresponded to the pH of formation of the hydrolysis products. With silica dispersions, at low coverage of hydrolysis product, the attractive forces contributing to the yield stress are charged patch and bridging. At high surface coverage at the pH of maximum yield stress, the increased in the effective Hamaker constant by the hydrolysis product is responsible for the enhanced van der Waals attraction.

Item ID: 2535
Item Type: Article (Research - C1)
ISSN: 1873-328X
Keywords: yield stress; adsorption; zeta potential; forces; metal ions
Date Deposited: 23 Jul 2009 01:38
FoR Codes: 03 CHEMICAL SCIENCES > 0306 Physical Chemistry (incl Structural) > 030699 Physical Chemistry (incl Structural) not elsewhere classified @ 40%
03 CHEMICAL SCIENCES > 0302 Inorganic Chemistry > 030204 Main Group Metal Chemistry @ 30%
03 CHEMICAL SCIENCES > 0306 Physical Chemistry (incl Structural) > 030603 Colloid and Surface Chemistry @ 30%
SEO Codes: 84 MINERAL RESOURCES (excl. Energy Resources) > 8403 First Stage Treatment of Ores and Minerals > 840305 Concentrating Processes of Base Metal Ores (excl. Aluminium and Iron Ores) @ 51%
86 MANUFACTURING > 8611 Basic Metal Products (incl. Smelting, Rolling, Drawing and Extruding) > 861199 Basic Metal Products (incl. Smelting, Rolling, Drawing and Extruding) not elsewhere classified @ 49%
Downloads: Total: 4
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page