Zeolite Modification And Removal Of Nitrogen And Phosphorus In The Water

The physiochemical modifications of zeolite,which aims at improving its ion exchange properties, enhancing its capacity of removing pollutant and further widening its application, have been a promising research project in recent years.The modification methods of zeolite from Jinhua Zhejiang, in terms of inorganic, organic methods, have thoroughly and systemically investigated in this paper, which were based on the reviews of recent literatures on zeolite modifications. The optimum modifying conditions, the affecting factors and mechanism for HDTMA-zeolite to absorb ammonium-iron and phosphate were investigated for exploitation and reproduction of zeolite mineral. From the experimental results, some conclusions could be drawn as follows:1. Natrolite, modified by sodium chloride solution , possesses NH₄⁺ saturation exchange capacity of 1.44mmol . g^-1, which is above twice that of natural zeolite.2. Hexadecyltrimethlammonuium (HDTMA)-zeolite is initially used to remove phosphate in water. The results show that the zeolite need to be washed three times and then heated at 102℃ before modification. Moreover, the optimum concentration of HDTMA is 3g . L^-1 and the reaction time is 12h. Under alkaline conditions and 1h shaking time , the adsorption efficiency for phosphate increased with the addition of obtained air-dried HDTMA-zeolite. With the increase of phosphate concentration,the adsorption capacity increased, and was about ten times that of raw zeolite.3. The activated zeolite, modified by aluminum sulfate (Al₂(SO₄)₃) and magnesium chloride(MgCl₂), could remarkably improve the ability to remove phosphate from aqueous solution. The adsorption capacity of the modified zeolite was about 10 mg . g^-1.