Assembly And Operation Parameter Design Of Electrosorption Desalination Module

As water pollution becomes more serious,the shortage of fresh water seriously affects the development of human life and society.Over the past years,a variety of seawater desalination technologies have been developed to increase freshwater resources,and distillation,reverse osmosis and electro dialysis are the most common and widely used technologies among them.However,there are still many factors that limit its development.The common goal of the current researches is to improve the energy efficiency of water treatment technology with lower cost.Therefore,it is an urgent requirement for humans to seek a new and competitive technology to increase freshwater resources.Capacitive Deionization(CDI)is an electrochemical water treatment process that is not only expected to be a commercially viable alternative to treating water,but also saves energy.CDI technology with high removal rate and high cycle number is simple to operate and stable in effluent,besides,there is no secondary pollution during regeneration.This paper mainly optimized the electrosorption module,and simplified the construction process by using semi-closed splint and modular assembly.The operating parameters of CDI devices using foamed nickel and graphite paper as current collectors were investigated by using coconut shell carbon as adsorbent materials,and the performance of two devices were compared.The device with foam nickel as electrode has a high removal rate,while the device with graphite paper as electrode has low energy consumption and high unit adsorption amount.Isothermal adsorption equation fitting results showed that both the adsorption processes of two devices have higher adsorption rates.The CDI devices with foam nickel and graphite paper as the current collectors were further optimized by adding anion-cation exchange membrane to the surface of the electrode to get MCDI devices,which were subjected to single-stage test and multi-stage test.The ion exchange membrane was found to have significant effect on the improved performance of electrosorption device,and the single-stage test result was superior to the multi-stage test.Based on the electrosorption device with graphite paper as current collector,the effects of different ion exchange membranes on adsorption performance were investigated,and the kinetic equation was fitted to study the effect of ion exchange membrane on adsorption performance.The results show that the adsorption of MCDI under different voltages is consistent with the quasi-first-order kinetic equation and the adsorption performance of the homogeneous membrane is better than that of the heterogeneous membrane.However,the difference of performance of devices with different ion exchange membranes is small.Therefore,an inexpensive ion exchange membrane can be used to further reduce the cost of MCDI.