The Fabrication And Application Of Modofied Starch Flocculant

On the basis of researching on the mechanism and application of modified starchflocculant, we fabricate a kind of macromolecule organic flocculant--modified starchflocculant CSF. And we made some research on the results of using modified starch flocculant CSF for the oil wastewater treatment and dyeing wastewater treatment.The raw material of CSF is corn starch, which is extensive and cheap. After stirring and heating the mixture of corn starch, NaOH, AlCl₃ and Na₂CO₃, the characteristic of corn starch is modified, then we get the modified starch flocculant CSF. The optimum composing proportion is that corn starch: NaOH: AlCl₃ : Na₂CO₃ : water =11: 0.9: 0.8: 1.5: 267.Under this condition, we can get the 4% modifid starch flocculant CSF.The effect of using CSF and PAM for oil wastewater and dyeing wastewater treatment are compared. The results show that CSF's flocculating effects is better than PAM's. And with regard to the oil wastewater, the remove rate of COD, oil, light accrossing, and SS is 77.94%, 61.2%, 62.7%, 79.96%, respectively; to the dyeing wastewater, the remove rate of COD and chroma is 74%, 91%, respectively.According to the results of flocculating experiment, we conclude that the optimum reaction condition of CSF is that the optimum amount used for the oil wastewater treatment is 12mg/L, the optimum amount used for the dyeing wastewater treatment is 10mg/L, the optimum temperature is 5℃～30℃, the range of PH is between 6 and 8, the speed and time of stirring is respectively that the fast stirring speed is 200r/min and the fast stirring time is 30s, the slow stirring speed is 100 r/min and the slow stirring time is 3min.On the condition of getting a same effect of oil wastewater treatment (the ratio of COD disposal is 72.3%), the total cost of adopting the flocculant CSF and PAM to treat one ton oil wastewater is 0.008 yuan and 0.17 yuan, respectively. In other word, the flocculant CSF will save 0.162 yuan when we treat one ton oil wastewater. So the modified starch flocculant CSF is more economical than flocculant PAM and it is more useful and easier to popularize.