Study on modification of colloidal silica surface with magnesium ions

The prepared colloidal silica via ion exchange was modified by adding Mg+2 ions in the surface growth process of colloidal silica. The particle size of the modified colloidal silica was decreased by increasing the seed concentration, whereas that of colloidal silica was slightly increased as the seeds concentration exceed 15 wt%. But the trend of changes in surface area was completely reversed. Magnesium ions on surface of the modified colloidal silica were identified by the measurement of energy-dispersive X-ray spectrometry (EDS). After modifying with Mg+2 ions, the iso-electric point (IEP) of colloidal silica in pH∼2pH∼2 without modification, disappears over the whole pH range.

Modification of the colloidal silica in different conditions, low and high concentrations of seed and Mg+2, resulted in compounds with the different particle size distribution, stability and various morphologies.Figure optionsDownload as PowerPoint slide