Preparation And Application Of Modified Chitosan Magnetic Microscopic Particles

Water is the basic need to the human existence, however, with the drastic development of industry the problem of water pollution becomes more and more serious. Meanwhile, the continual improvement of the people's material living standard has caused great demand to the quality of water. As for the features of the current pollution of water, the dissolved organic matter and the non-biodegradation compound,etc have increased gradually year by year. But the effect of the present technical means on reducing water turbidity is not remarkable, and many current reagents used as water treatment may produce the second pollutant which is damaging to the environment.There is no doubt that it will have a harmful influence over the protection of environment and the continuing development. Therefore, nowdays seeking for the efficient, environmental and economic technology of water treatment without the second pollution should be the hot sopt and the foremost issue in the current research on the water treatment.The Fe₃O₄ nano-particles were prepared by co-precipitation method and modified by oleic acid;Then carboxymethyl chitosan magnetic microscopic particles were prepared by inverse suspension method with carboxymethyl chitosan prepared in Lab.. The results demonstrated that crosslinker type , the mass of crosslinker and the mass ratio of carboxymethyl chitosan and modified Fe₃O₄ ,et al. were the most effective parameters for the preparation of the microspheres. The IR and VSM verified that the carboxymethyl chitosan magnetic microscopic particles were successfully synthesized.The AFM, TEM and DLS indicated that the diameter of the microscopic particles were 5²0 nm .The TGA show that carboxymethyl chitosan magnetic microscopic particles have good thermal stability.And based on modified chitosan magnetic microscopic particles as a flocculant, the flocculability experiment on papermaking wastewater was carried out . Relations of flocculability with the dosage of flocculant, pH, agitation speed, agitation time and settling time were discussed. For the high COD value of the pulp and paper wastewater , the removing efficiency for CODcr is 56.52% under the best conditions. For the low COD value of the pulp and paper wastewater, the removing efficiency for CODcr is 29.56% under the best conditions. The removing efficiency for CODcr of the high value of the pulp and paper wastewater is better than the removing efficiency for CODcr of the low of the pulp and paper wastewater by the modified chitosan magnetic microscopic particle handling.It indicated that modified chitosan magnetic microscopic particle as a flocculant has more obvious effect for the high CODcr value of the pulp and paper wastewater.To the same removal effect, the flocculant can greatly reduce the CODcr value if modified chitosan magnetic microscopic particle was the initial flocculant. That may reduce unnecessary pulp and paper wastewater treatment steps, and then reducing costs and saving energy consumption.So it is a good method for treatment of pulp and paper wastewater by modified chitosan magnetic microscopic particles. At the same time, for the high CODcr value of the pulp and paper wastewater ,the the removing efficiency for SS is 52.14% under the best conditions; the chroma value was below 80 times under the best conditions, just meet the wastewater discharge standards of Pulp Enterprise.