Preparation And Effect Of Inorganic Polymeric Titanium-containing Flocculant

In this work, two kinds of newly flocculants poly-titanium-silicate-sulfate （PTSS） and poly-aluminum-titanium-silicate-sulfate （PATS） were prepared by the copolymerization using sodium silicate, aluminum sulfate and titanium sulfate as raw materials, their performance used in simulated kaolin low turbidity water treatment were evaluated.Moreover, structure and morphology of the prepared flocculants were characterized by FTIR, XRD and SEM, and the flocculation mechanism was analyzed elementary. Finally,the cost and social values of PTSS and PATS.By comprehensively studying the effects of factors such as concentration of SiO₂,aging pH value and aging temperature on stable time of polysilicic acid, the optimized technological condition was obtained: Under the conditions of room temperature 20～25 ℃,the initial pH value of the silicate solution was adjusted by dilute sulfuric acid to 3, and the SiO₂ concentration was controlled form 0.6 mol/L to 0.7 mol/L.The effects of the molar ratio Ti/Si, aging time, the pH value of water, water temperature on PTSS treating kaolin simulated low turbidity water and settling performance of floc formed were investigated, the results showed that the molar ratio of Ti/Si is 1:1,aging time is 10～15 h,flocculation performance is better. PTSS is suitable for pH value of water is 6～8, water temperature is 10～20 ℃. The flocs formed by PTSS can be completely deposited within 20 min.The effects of the molar ratio of Al/Ti and （Al+Ti）/Si, pH value of water and water temperature on the flocculation and residual aluminum content of PATS and floc settling performance were investigated. It was found that the synthetic PATS showed the best coagulating effect and lower residual aluminum content in treated water with the followed experiment condition: n（Al）/n（Ti） is 10:1,n（Al+Ti）/n（Si） is 1:2, initial pH is from 7 to 9,water temperature is 10 ℃.Structure and morphology of the prepared flocculant were characterized by Fourier transform infrared spectroscopy （FT-IR）, X ray diffraction （XRD）, scanning electron microscopy （SEM）, the results showed that the Ti-O-Si bonds could be formed between titanium and silicon in PTSS, Ti-O-Si and Al-O-Si bonds could be formed between Ti-Si and Al-Si in PATS. PTSS and PATS are amorphous polymer rather than simple mixture of raw materials. Morphology analysis showed that the PTSS and PATS formed a chain network structure, which is conducive to the adsorption of colloidal particles in the water,achieve a better flocculation effect.The cost and social benefits of the two flocculants were investigated, the results show that the cost of producing 1 t PTSS is 3420.85 Yuan, and the cost of producing 1 t PATS is 424.58 Yuan. All or part of aluminum was replaced by titanium to copolymerize with polysilicic acid, leading to reduce the use of aluminum salt, which means reduce the excessive consumption of aluminum to some extent.So it has great social benefits.