Study On The Efficiency Of MCDI On Reducing Fluoride And Sodium In Drinking Water Of Villages And Towns

With the rapid development of social economy,the requirement of drinking water quality is constantly improving.Due to the influence of geological structure,the salinity of groundwater in Zhaodong city of Northeast China Plain is generally high,and fluoride exceeds the standard;At present,the main source of drinking water in Zhaodong city is the untreated shallow groundwater.Fluoride and sodium exceed the standard seriously,which will seriously harm human health if drinking for a long time;Membrane capacitive deionization(MCDI)has the advantages of low energy consumption and no need to add chemical reagents,which has the potential to be used in the removal of ionic pollutants in rural drinking water;This project will carry out the research on the effectiveness of different structures of MCDI to reduce fluoride and sodium in drinking water source of villages and towns,optimize the operation parameters,design and process a set of highefficiency,energy-saving and easy to operate MCDI equipment,reduce fluoride and sodium in drinking water source of villages and towns,and ensure the safety of drinking water quality of villages and towns.In this project,two different structures of MCDI devices were designed to remove fluoride and sodium,and the process parameters such as working voltage,inflow flow,plate spacing,plate pairs and backwash mode were optimized.Under the optimal process parameters,the mechanism and efficiency of MCDI to reduce fluoride and sodium in rural drinking water source were studied;The performance of the device was analyzed by characterization;Finally,on the basis of small-scale experiment,the pilot plant of MCDI was enlarged to carry out the pilot test of defluorination and sodium reduction of drinking water in villages and towns of Zhaodong area,and the effluent quality indexes such as conductivity,dissolved solids,p H,turbidity,fluoride,chloride,sulfate and sodium ion were monitored.The results show that the effect of MCDI on fluoride removal and sodium reduction is better.Results of plate MCDI pilot test: under the optimal operating conditions,the lowest fluoride concentration in the effluent after 50 mg/L fluoride treatment is 37.01mg/L,the ion removal capacity is 1.73 mg/g,the average ion removal rate is 15.5 %,the energy consumption per unit adsorption capacity is 16.29 w/mg,and the charge efficiency is 49.38 %.The results of volume MCDI small-scale experiment: under the optimal operating parameters,the minimum fluoride concentration of effluent after 50 mg/L fluoride treatment is 36.07 mg/L,the ion removal capacity is 12.52 mg/g,the average ion removal rate is 25.04 %,the energy consumption per unit adsorption capacity is 13.29w/mg,and the charge efficiency is 76.40 %;The results show that the performance of coil mcdi is better than that of plate mcdi.The results show that the optimal operation voltage is 5 V,the optimal influent flow rate is 1 L / min,the average removal rate of fluoride and sodium ion is 21.4 % and 17.54 %,respectively;The results showed that the average removal rate of fluoride,sodium and water was 45.37 %,17.45 % and 58.33 %,respectively.The results show that the effect of MCDI device on reducing fluoride and sodium in rural drinking water is obvious,and the water quality indexes of the effluent in the operation stage reach the drinking water quality standard,which has the production and operation potential for defluorination and sodium reduction in rural drinking water.