Removal Of Fluoride From Water By Removing Phosphorus, Arsenic And MIL-101 (Cr) From Water By MIL-88 (Fe)

Accompanying with the rapid development of industry and agriculture, the resulted waste water also accumulated rapidly, which greatly threatened to human lives and the ecological environment. The majority water systems of our country were stuck into the issue of water eutrophication, phosphorus is the main evil of eutrophication of water; at the same time, the contamination of arsenic and fluorine also seriously affect the people’s health and lives. Physical absorption on contaminants is a useful method been frequently used in the waste water treatment, it holds the simplest technics and other many features. Metal organic frameworks (MOFs) is a new functional material, with merits of unique internal arrangement rules, special pore size and shape, unsaturated coordination sites. And it has been greatly used in the field of catalysis and adsorption. In this thesis, MOFs were used as the absorbent to remove the phosphorus, arsenic and fluoride ions from the waste water.The MIL-88(Fe) was used for removal the phosphorus in water solution. We investigated several key factors for the absorption properties of MIL-88(Fe), such as phosphorus concentration, reaction time and the pH of water solution. The results indicate that MIL-88(Fe) shows the superior absorption behavior to phosphorus contaminant. The adsorption capacity as high as43mg·g-1, and it could be reach their equilibrium at6h. In addition, this absorption process strongly affected by the pH value of solution. The dynamics investigation shows that Lagergren pseudo-second order kinetic model can be used to describe the adsorption process. Furthermore, Langmuir isotherm can be used to describe the adsorption behavior of MIL-88(Fe) in phosphorus solution. MIL-88(Fe) also used for the remove of arsenic ions in water, we studied how the concentration of arsenic, reaction time and the pH value of the solution affected the absorption property. The outcome indicated that MIL-88(Fe) with the good absorption property to arsenic ions, but the absorption rate relatively low and need12h to reach the adsorption equilibrium. When the pH value of the solution between5and7, the material shows the best absorption capability for removal arsenic. The Langmuir isotherm can be used to reflect the behavior of adsorption on arsenic. MIL-101(Cr)was synthesized and used as adsorbent for remove of fluoride ions in waste water. We investigated the influence of concentration of fluoride ions, absorption time and pH value of solution to absorption property. The result show that the adsorption capacity of the metetial adsorbed fluorine is17mg·g-1, and it could reach their equilibrium with in2h. Similarly, this process also greatly affected by pH value of solution. Lagergren pseudo-second order kinetic model can be used to describe this adsorption process. Furthermore, Langmuir isotherm can be used to describe the adsorption behavior of MIL-101(Cr) absorption on fluoride ions.