Effects Of Several Organic Compounds On The Formation Of Silica

In the process of the water recycling system, the water evaporating make the silicic acid concentrated in the water, and form the silica scaling on the inner wall of the pipeline equipment, do some harm to industrial production. Silica scaling is the precipitation which polymerize from silicic acid in the aqueous solution. The paper from the interaction of silicic acid and organic matter, selected the sodium salicylate, disodium phthalate, sodium citrate and EDTA disodium, investigated their effects on silicic acid precipitation and its mechanism. Accumulate data for the study of inhibitors of silicic acid. By measuring the change of monosilicic acid and total acid concentration, sodium salicylate and disodium phthalate have promoting effect on polymerized precipitation of silicic acid, and the promotion effect of sodium phthalate on the polymerized precipitation of silicic acid is larger than sodium salicylate. The 29Si NMR spectroscopy shows that disodium phthalate and sodium salicylate cannot form new complexes with silicic acid. By the determination results of infrared absorption spectrum and Zeta potential, disodium phthalate and sodium salicylate both are combinated hydroxyl or carboxyl on the benzene ring with the Si-OH on the surface of polysilicic acid, and adsorption on the surface of polysilicic acid, promoting the polymerized precipitation of silicic acid. However, sodium citrate and EDTA disodium have inhibitory effect on the polymerized precipitation of silicic acid, and the inhibition effect of EDTA disodium on the polymerized precipitation of silicic acid is larger than sodium citrate. The full wavelength scanning of the UV-VIS spectrum shows that sodium citrate and EDTA disodium could form complexes with silicic acid, in order to inhibit the polymerization of silicic acid. In the aqueous solution, silicic acid and citric acid can form 1:2 complexes, silicic acid and EDTA can form 1:1 complexes.