Study On Removal Of High Concentration Chlorine Ion

The chloride content in industrial wastewater and external drainageis is relatively high,if not dispose and achieve standard to discharge directly,it will have an impact on the water balance and be a serious harm to groundwater and drinking water resources.At present,chlorine ion treatment methods are precipitation salt,evaporation,electrochemical method,ions exchange,oxidation reduction and so on.In these methods,salt precipitation method is effective and easy to operate,but it has a large gap between input and output,so it has been in the basic research stage and less industrial applications;evaporation concentration method is generally used to deal with the high chloride concentration wastewater,but the energy consumption is high and higher requirement for equipment;electro adsorption method is suitable for the wastewater with low concentration chlorine ion,in order to achieve a better effect,it should be increased the voltage or the area of the plate,but the two methods will increase cost and energy consumption;ions exchange is a chloride ion treatment method very early,it has been used for a long time,the technology is more mature,but the cost of ions exchange resin is too high,the regeneration process is more complex and high cost of operation,microorganisms on its surface are easy to proliferate;oxidation reduction method consumes much water and electricity,needs a lot of cost.Therefore,we should find a economic and effective method for the removal of chlorine,which is cheap and environmentally friendly.Most of the industrial wastewater and external drainageis contain high concentration of Cl^-,a lot of SO₃^2-,and a part of SO₃^2-charge into SO₄^2-in the process of wastewater treatment.So,after to remove Cl^-in wastewater,we should remove SO₃^2-and SO₄^2-.Otherwise,it will affect the normal industrial production and cause certain hazards to the ecological environment.Through investigation and study,I use the ultra high aluminum lime method,adding CaO and NaAlO2 into chlorine wastewater,Ca2+ 、 Al3+ and Cl^-reacte to form the minimum solubility of calcium aluminum chloride layered compound which is Ca4Al2Cl2（OH）12,it is a simple and economical method for removing chlorine.I use the CaO precipitation method on removal of SO₃^2-effectively,that is to say,SO₃^2-and Ca2+ generate CaSO3 and remove SO₃^2-.At first,I determine the ultra high aluminum lime method,s n（Ca）:n（Al）:n（Cl）is 12.0:3.6:1.0,study on the experimental conditions of high speed and low speed to remove the Cl^-.Under high speed condition,the stirring speed is 5000 rpm,the stirring time is 10 min and the reaction temperature is 20℃,the Cl^-removal rate up to86.09%.Under low and medium speed mixing condition,the stirring speed is 80 rpm,the stirring time is 20 min and the reaction temperature is 20℃,the Cl^-removal rate up to 73.67%.The experimental conditions for the removal of SO₃^2-is n（Ca）:n（S）=4.6:1.0,100 rpm of stirring speed,20℃of reaction temperature,20 min of stirring time.When the initial concentration of SO₃^2-is 9387.00mg/L,the SO₃^2-removal rate up to 98.67%.Furthermore,the experiment explore the effect on different concentration of SO₃^2-removal;the removal effect of the Cl^-and SO₃^2-by total reaction time and concentration of Cl^-;the removal effect of the Cl^-by SO₃^2-and SO₄^2-;at last,I add a part of CaO and NaAlO2 in the removal of Cl^-and SO₃^2-experimental precipitation,enabled CaO and NaAlO2 to achieve the initial total amount of experiment,when the original SO₃^2-at different initial concentration,to explore the removal of the two ions in original solution.