抄録
Effect of cethyltrimethylammonium bromide (CTAB) on the precipitation of silica from geothermal water was examined. CTAB did not react with monosilicic acid and only polysilicic acid was precipitated by CTAB. There was an optimum pH for the precipitation of silica. Polysilicic acid was precipitated more easily with increasing their particle size. In the concentration range of 10-7 -10-4 mol dm-3 of CTAB, the amount of precipitated silica inreased with increasing concentration of CTAB and most of polysilicic acid was precipitated at CTAB concentration of 10-4 mol dm-3 within 5 min. It is suggested that the decrease in the negative charge on polysilicic acids due to the electrostatic adsorption of cethyltrimethylammonium (CTA+) ions on the surface of polysilicic acids and the hydrophobic interaction between CTA+ ions adsorbed on different polysilicic acids accelerate polymerization reaction between polysilicic acids to cause precipitation of silica.
