Research On The Fluorine Removal From Raw Water By Complexation-Ultrafiltration

At present, there are nearly one hundred million people living in high fluoride areas in china, up to tens of millions of people suffer from effects of victims.Except for few of areas are effected by natural factors, a large number of industrial wastewater with fluorine discharge to the natural water is one of the main reasons causing fluoride pollution.In addition, with the extensive application of organic fluoride, fluorine on en vironmental pollution, especially on the water Resources pollution is increasing.Exce-ssive fluoride from industrial waste water will pollute the environment and do harm to the crops and livestock;Moreover,it will seriously affect the health of human. Therefore, for protecting the environment, improving people's quality of life, the key technology research of high fluoride water is very important in the field of environmental protection and health all over the world.Fluoride is widely existence in natural water.It is one of essential trace lements. According to 《hygienic standard of drinking water》 GB5749-2006in China, fluoride concentration of life drinking water should not exceed1.0mg/L.China provides drinking water fluoride content suitable for0.5～1.0mg/L,when the fluoride concentrations of drinking water lower than0.5mg/L,the susceptibility to caries disease.However,if long-term consumption of fluoride concentrations greater than1.0mg/L of water,easy to cause dental fluorosis,fluoride concentration of long-term consumption of5～10mg/L of water would cause bone fluorosis. Defluorination of drinking water and people's health is closely related to becoming more and more attention.The technologies of fluoride removal from drinking water were analyzed, such as deposition,adsorption,on exchange, electro-coagulation, electro-dialysis and reverse osmosis, and so on.Then the research future of the above technologies were predicted.Meanwhile,the mechanism of each method was discussed.And the combined process of fluoride removal can better meet increasingly stringent water quality standards and becoming to the most promising methods. In this paper,By using the Polyaluminium Chloride Complexation and the combination method of Ultrafiltration to treat high fluoride water in the laboratory,under certain conditions,ultrafiltration membranes with a combination of coagulation process can achieve a satisfactory effect of fluorid removal. According to comparison and selection of the defluoridation,the effect of defluoridation by Polyaluminium Chloride is superior to iron salts,and the optimum time at10to20minutes is better.And the PH is an important factor in the process of coagulation and Ultrafiltration technology,it can not be ignored in the actual operration In the pretreatment membrane separation proeess,a suitable PH can enhance the effect of pretreatment reduce membrane fouling enhance flux through the experiment,best PH value of coagulation and UF technology is between5.7-7.2. The effects of anions largely influences the defluorination in this process,and the effect of temperature is small. At the same time,study on the Secondary Pollution of the aluminum,found the polymeric aluminum ferric chloride(PAFC) can remove residual aluminum concentration in drinking water better.Ultrafiltration technique because of its good water quality and effectiveness of stability,small footprint,easy-to-the advantages of automation have been concerned about the wide range of workers,water treatment and drinking water has been dealing with the initial application.But in the process of application of ultrafiltration membrane to the most pollution,the environment and operating conditions have a greater impact and other issues needed further study。Appropriate pre-membrane ultra-filtration membrane technology and can greatly improve the drinking water with fluoride ion removal effect.In the experiment through backwashing,and flux can get part of recovery.For the effect of fluoride removal, membrane price,running costs and membrane fouling,and so on,We considered that combined process, espeeially Complexation-Ultrafiltration proeess,no doubt that it will be the best drinking water fluoride removal technology. With Prices declining of the membrane, Complexation-Ultrafiltration technology in drinking water fluoride removal application will be better prospects.