Preparation And Properties Of The New Polysiticate-metat-chitosan Composite Flocculants

In this paper, chitosan, zinc sulfate, magnesium sulfate, sodium silicate, aluminumsulfate were used as main raw materials to prepared two kinds of flocculants. NamelyPoly silicate-sulfate alunminum zinc-chitosan(PSAZ-CTS for short) flocculant, the otheris Poly silicate-sulfate alunminum magnesium-chitosan(PSAM-CTS for short) flocculant.The paper studied the impacts on the two kinds of flocculants with the factors of M/Simolar ratio, Al/Zn (or Mg) molar ratio, M/CTS mass ratio, reaction temperature, reactionpH, aging time, flocculation conditions, etc.Using FT-IR spectroscopy to study the chemical bonding of polysilicate, chitosan,metal ions. Using the X-ray diffraction analytical method to study the interaction amongthe polysilicate, chitosan, metal ions and their hydrolysates, The morphology of twokinds of flocculant were observed by an scanning electron microscopy. Finally, the paperdiscussed the economic and social value of PSAZ-CTS and PSAM-CTS.Experimental results and analysis indicated that all of M/Si molar ratio, Al/Zn (orMg) molar ratio, M/CTS mass ratio, reaction temperature, reaction pH, aging time,flocculation conditions, etc, did a certain effect on the flocculating property of the twokinds of flocculants. For PSAZ-CTS flocculant: When the M/Si=1/1, Al/Zn=5/1,M/CTS=4, the reaction temperature was40℃, the reaction pH was1.4, the agingtime was1d, PSAZ-CTS flocculant showed the best treatment effects on Songhuariver, the removing rate of turbidity and chroma was97.19%,96.08%. As PSAM-CTSflocculant: the best treatment effect on Songhua river was the M/Si=0.8/1, Al/Zn=10/1,M/CTS=8, the reaction temperature at60℃, the reaction pH met1.32and theagingtime was1d. In this condition the removing rate of turbidity and chroma was96.62%and95.63%. The above test proved that the two flocculants had such properties aslower dosage (1mL/500mL), adapted to a wide pH (7-9) range. Also, had a relativelygood treatment effects on low-temperature sewage, turbidity removal reached about97%, chroma removal reached90%. The characteristic peaks of metal ions bonded with polysilicic acid and chitosanwhich appeared on the FT-IR spectra of PSAZ-CTS flocculant and PSAM-CTSflocculant, it proved chitosan, polysilicic acid and metal ions linked together in thereaction. However, the X-ray diffraction analysis indicated that the reaction betweenpolysilicic acid, chitosan and metal ions occured and something of amorphous polymergenerated. Both of flocculants folded up into complex three-dimensional forms under thescanning electron microscope, which made it easier to bridge and net colloidal particlesin water. Through the analysis, there was a certain considerable social, economic benefitfor PSAZ-CTS flocculant and PSAM-CTS flocculant, the prospects worth definitelyexpecting.