[Analysis of reaction process between Si and Fe in poly-silicic-ferric sulfate (PSF) coagulant].
A new inorganic polymer coagulant, poly-silic-ferric sulfate (PSF) with various Si/Fe ratios (PSF0.5, PSF1 and PSF denote Si/Fe molar ratios of 0.5, 1 and 3, respectively), was prepared using water glass, ferrous sulfate and sodium chlorate by co-polymerization, and pH value was measured during the preparation process. The influence of both Si/Fe ratio and reaction time (polymerization time) on the complexation process (bonding mode) between Si and Fe was explored with many analytical methods (such as X-ray diffraction (XRD), ultraviolet/visible absorption (UVA) scanning, transmission electron microscope (TEM), photon correlation spectra (PCS) and infrared spectrum (IR) using PSF samples taken from different reaction time at different Si/Fe ratios. The results show that the characteristics of PSF are largely influenced by both reaction time and Si/Fe ratios. PSF is found to be a complexation compound of Si, Fe and many other ions, instead of a simple mixture of raw materials. The complexation process between Si and Fe may be different from various Si/Fe ratios, namely, the bonding rate, bonding mode and the stability of the bond between Si and Fe are different from various Si/Fe ratios: the polymer based on Si-O-Fe-O-Fe-O-Si bond may be formed at low Si/Fe ratio, in comparison with that based on Si-O-Fe-O-Si-O-Si bond at high Si/Fe ratio; the formation rate of Fe-O-Fe bond is rapid and there may be a mutual acceleration between Fe-O-Fe bond and Si-O-Fe bond, while the formation rate of Si-O-Si is slow and maybe there is a mutual retardation between Si-O-Fe bond and Si-O-Si bond; the stability of Fe-O-Fe bond is weaker than that of Si-O-Fe or Si-O-Si bond.
Fu
Ying
Y
School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. fuying8899@163.com
Yu
Shui-Li
SL
Yang
Yuan-Jing
YJ
Lu
Yan
Y
D005290:Ferric Compounds / Q000737:chemistry; D005427:Flocculation; D007501:Iron / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013464:Sulfuric Acids / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D005290:Ferric Compounds; D011108:Polymers; D013464:Sulfuric Acids; D014874:Water Pollutants, Chemical; C024823:ferric sulfate; D012822:Silicon Dioxide; D007501:Iron; C033158:sulfuric acid; D012825:Silicon