The Research On Chitosan Mixed Modified Diatomite For Cyanobacteria Removal And PHospHorus Values Reduction

Eutrophic pollution prevention and control of water pollution and environmental engineering is an important direction, mainly eutrophic pollution and harm to China's frequent outbreaks of water and caused a series of questions. After the outbreak of water bloom control is mainly reflected in the removal of algae on the individual. While before the outbreak of water bloom control is mainly reflected in the water balance of ecosystems in its maintenance, which is the most important part of the control of nutrient concentrations in water. As people continuously improve environmental and ecological awareness, environmentally safe and effective treatment methods as eutrophication control development.Based on the research at home and abroad, this article is phosphate gradient solution in the experimental production by Zhejiang Shengzhou Melosira diatomaceous earth as raw material, ferrihydrite, under certain conditions of its use to load, modification, and use the modified diatomite for phosphorus removal. On the microstructure before and after modification of diatomite with changes in the relationship between changes in adsorption properties were discussed and studied in different pH value of water under their TP removal efficiency. In addition, this paper also cultured in artificial conditions the solution of microcystis aeruginosa in the experimental.Using previously prepared chitosan modified diatomite with the algae fluid coagulation test. The modified diatomite surface electrical properties, particle size, the best delivery of chitosan and different pH than the coagulation effect was under further study.The results show that in the NaOH treatment, surface SiO2 of diatomite was partially dissolved in the NaOH solution. The dissolved Si contributed to form the stable ferrihydrite which deposited into the macropores and mesopores of diatomite. Blocking macropores and larger mesopores of diatomite with ferrihydrite resulted in a specific surface area of 197.6m2/g for the ferrihydrite-modified diatomite, which is 7 fold increase than the raw diatomite (26.77 m2/g). Because of the increased surface area and surface charge, the maximum adsorption capacity of ferrihydrite-modified diatomite at pH 4 and pH 8.5 was increased from 10.2 mg P/g and 1.7 mg P/g of raw diatomite to 37.3 mg P/g and 13.6 mg P/g, respectively. Use of the modified diatomite with the coagulation of chitosan on the algae test results showed that the modified diatomite mixed with chitosan on algae removal by coagulation flocculation removal rates far higher than the two independent, with good removal efficiency. Analysis of the reasons, the use of chitosan and modified diatomite for coagulation, not only through the bridging role of the bond chitosan flocculation of algal cells, but also to change the diatomite surface electrical properties, cohesion of algal cells with negative. Therefore, the coagulation ability of Microcystis aeruginosa increased significantly. Experiments show that, (30+1) mg/L can be an effective use of flocculation and removal of Microcystis aeruginosa removal rates reached 93% (pH= 8.5) and 99% (pH= 4) or more.