Modification And Investigation Of Flocculating Property Of The Natural Polymer Flocculant Chitosan

Chitosan is a kind of inartificial organic compound of macromolecule in nature. The advantages of chitosan can be listed as: abundance, high yield, with no poisonous side-effect, complete biological decomposition, powerful sorption adsorbing of metal-ions, dyeing-ions, halogen, protein, amoino- acid, clay grain and so on. And it is a powerful germicidal and germ- repressing compound, which makes it can be used as a multifunctional flocculent in the treatment of wastewater.Because when we use chitosan (CTS) seperately, the effect of flocculation capability is lower at general acid condition (pH=7-9).The writer of this paper tried to enhance the capability of removing electionegative grain from the wastewater on the way of altering the natural structure of chitosan and using its chemical sorption effect. At the same time, we can integrate its powerful adsorbing capability with its capabilities of COD, SS and metal-ion removing.As Fe³⁺ for a modifier, the research prepared chitosan complex iron flocculant (Fe-CTS), we can achieve the optimization technology of the test is: First solution will be made from chitosan, then Fe³⁺ for the modifier with chitosan complex, and adjust the measurable acidity to promote the hydrolyzing of complex compound of Fe³⁺, the concentration ration of the complex flocculant is CTS: Fe=2:1. We can make the acidity of Fe-CTS lower than previous CTS, make the hydrolyzing weaker, and get the more stabile solution; what's more, we can achieve a better flocculating efficiency and enhancing removing double phosphorus in dealing with the wastewater. Using a standard method of testing chitosan complex iron on the performance of wastewater flocculation, it shows that the sedimentation rate with kaolin is 88.75% when the pH is 7, and has not regulated wastewater acidity,water acidity is essentially the same characteristics. The control test results showed that the water quality in the same conditions, the flocculating behaviors of the Fe-CTS flocculant is significantly better than the Chitosan,PFC and Polyeriron- Chitosan, it further explain chitosan and iron is not a simple compound, but a reaction product.