The Method Study On SO₄^2- Removal From High Sulfate Containing Drinking Groundwater In Sichuan Province

In recent years, the shortage of freshwater source is more and more serious, so the exploitation of underground water is becoming urgency. About 5% ground water has a high level of SO₄^2- in Sichuan province .It was reported that diarrhea may be associated with water that contains high levels of sulfate. In the livestock production industry, there is a concern that high levels of sulfate in water can adversely affect productivity. Different methods can be used to remove sulfate from water.But methods that study on SO₄^2- removal from high sulfate containing drinking groundwater weren't found .Based on the strong adsorbability of iron hydroxide and aluminum hydroxide to anion and cation, this paper study firstly on SO₄^2- removal from high sulfate containing ground water in Sichuan province by iron hydroxide adsorption method and aluminum hydroxide adsorption method,offering practicable ways for the treatment of high sulfate containing groundwater.In the research on the use of iron hydroxide adsorption method removal SO₄^2- , we got a better result .Used a series of condition experiment to analyze the influencing factors of SO₄^2- removal one by one, getting the optimum reaction condition: mass ratio SO₄^2-/Fe³⁺ = 0.1, PH=4, at normal temperature, stir 10min .In this condition, the SO₄^2- removal ratio reached more than 90%.The reaction was exothermic reaction and we got a better result at normal temperature. This adsorption process fitted Langmuir adsorption isotherm better and the largest adsorption capacity was 50.43 mg/g.when we used iron hydroxide adsorbent to mange the high sulfate containing drinking groundwater in Sichuan province, the SO₄^2- removal ratio could reach more than 90%.The concentration of SO₄^2-.Fe³⁺ and Cl- in the ground water was lower than the national sanitary standard for drinking water. In the research of removing SO₄^2- by aluminum hydroxide adsorption method, we analysised the influencing factors of SO₄^2- removal, by arranging a series of condition experiment. The experimental results showed that: mass ratio SO₄^2-/Al3+=0.6, PH=5～5.5,at normal temperature ,stir 10min ,the SO₄^2- removal ratio reached more than 90%. Because the temperature had little effect on the removal ratio of SO₄^2-, it may choose to carry out at normal temperature in the actual application. This adsorption process fitted Langmuir adsorption isotherm better and the largest adsorption capacity was 25.21 mg/g.when we used aluminum hydroxide adsorbent to mange the high sulfate containing drinking groundwater in Sichuan province, the SO₄^2- removal ratio just reached more than 75%.The concentration of Al3+ and Cl- in the groundwater was lower than the national sanitary standard for drinking water.Iron hydroxide adsorbent could effectively remove SO₄^2- from high SO₄^2- containing drinking groundwater in Sichuan province and can solve the regional lack problem of drinking water in Sichuan Province. But removing SO₄^2- by aluminum hydroxide adsorbent didn't have good result and only was used to deal with the drinking groundwater that SO₄^2- content is lower than 1000mg/L.