Preparation And Performance Of Polymerized Silicate Containing Aluminum Sulfate And Zinc Sulfate Flocculant

Flocculant is one of the necessary materials used in water treatment.At present, flocculantsbased on aluminum and ferric salts are chiefly used abroad and in China, while the low efficiencyproblems by the aluminum salt and the corrosion problems by the ferric salt are still need to besolved. In this paper,a novel inorganic polymer composite flocculant—PAZSS (poly-aluminumzinc silicate sulfate) was synthesized by sodium silicate(Na2SiO3),aluminum sulfate(Al2(SO4)3)and zinc sulfate(ZnSO4) under normal temperature and pressure. Then physicochemicalcharacteristics and mechanic of PAZSS and its application were also studied.The influences of the concentration of Na2SiO3, the Al/Zn and (Al+Zn)/Si molar rate onflocculation were investigated by single factor experimenrs. The optimum preparation conditionsof PAZSS were got by flocculation experiment: the concentration of Na2SiO3is0.4mol/L; theactivation pH value is4.0; the polymerization time is30min; the molar ratio of Zn/Al is1.0; themolar ratio of (Al+Zn)/Si is1.0; aging reaction time is24h.The interaction among polysilicate acid, Al(III), Zn(II) and their hydrolyzate were analysedby using X-ray diffraction and Infrared Spectroscope. The results show that some complexingactions exist among the Polysilicate, Al(III) and Zn(II), the flocculant is not only a simple blend,but different compontents have formed amorphous polymer. The microstructure characteristics ofPAZSS have been analysed by photoelectric microscope and SEM, and the results show thatdifferent preparation methods have great effect on structure and figure of PAZSS. Polysilicate,Al(III) and Zn(II) had trend to form chainlike and branched structure. Structure characterizationsof PAZSS is different from the structure of polysilicate acid, it has great flocculation efficiencybecause of its special web-like structure.In order to test practice effect in sewage treatment, dyeing waste water and polysilicongrinding waste water were to get disposal by using PAZSS. The flocculation efficiency of PAZSSwas compared with the flocculation efficiency of PASS, PAC and PFS as well. Colour removalrate and CODCrremoval rate were90.3%and88.3%respectively, when was used in dyeing wastewater treatment. And when it was used in polysilicon grinding waste water treatment, the turbidityremoval rate reached to99.7%and CODCrremoval rate attained to85.7%with the best dosage.The results show that the performance of PAZSS is better than PASS, PAC and PFS.