Acceleration effect of sulfate ion on the dissolution of amorphous silica

• Published in: Journal of colloid and interface science Vol. 331; no. 2; pp. 551 - 554
• Main Authors: Bai, Shuqin, Urabe, Shinji, Okaue, Yoshihiro, Yokoyama, Takushi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.03.2009
• Subjects: Dissolution constant; Effect of sulfate ion; Silica; Specific adsorption; Zeta potential; Dissolution constant; Specific adsorption; Zeta potential; Silica; Effect of sulfate ion
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2008.11.076

The dissolution rate of amorphous silica is enhanced by sulfate ions. The zeta potential for silica particles in Na 2SO 4 solution was lower than that in NaCl solution with the same ionic strength. These facts indicate that the specific adsorption of sulfate ions occurred by overcoming repulsion between negative charges of the SO 2− 4 ion and Si O − on the surface of silica. The dissolution rate of amorphous silica may be accelerated by the specific adsorption of SO 2− 4 ions because of a decrease in the strength of the Si O Si bond in amorphous silica due to donation of electron density from the adsorbed SO 2− 4 ions. The dissolution of amorphous silica is accelerated by specific adsorption of sulfate ion on the surface of silica. (▴) Pure water. (●) 0.3 M sodium chloride. (■) 0.1 M sodium sulfate.