Study On The Preparation Of Functional Carbon Nanotube Electrodes Through Electrophoretic Deposition And Its Application In Capacitive Deionization Process

The Capacitive Deionization Technology?CDI?is widely paid attention by researchers as a novel desalination technology.The CDI electrodeboth depends on the character of the electrode material and the electrode fabrication technology.Therefore,this article studied the Electrophoretic Deposition?EPD?strategyas a novel electrode fabrication technology,graphite paper and carbon nanotube?CNT?were used as current collector and active electrode material,to focus on the effects of the electrode performance by adjusting the preparation conditions.The optimized preparation condition of the deposited CNT electrode werem_CNT:m_addictive=5:1,the deposition time of 30 min and the electric field intensity of 15 V/cm.The deposited electrode and the coated electrode were investigated with the same amount of CNT.The results indicated the specific capacitance?66.72F/g?and the specific adsorption capacity?23.93mg/g?of the deposited electrode were 1.62 and 1.85 times those of the coated electrode and with lower ion transport resistance.The results showed that the deposited electrode shows better electron storage capacity,faster current response and higher ion adsorption capacity.In this paper,to improve the CDI desalination performance,oxidized CNT?ox-CNT?,hydrothermal nitrogen-doped?N-doped?based on pristine CNT?N/CNT?,hydrothermal N-doped CNT based on ox-CNT?H/N-O-CNT?and sintering N-doped CNT based on ox-CNT?S/N-O-CNT?were prepared,respectively.These four kinds of modified CNT materials and pristine CNT were all studied by material characterizations.The results indicated that there were obvious crimps and branches appeared on the outer walls of H/N-O-CNT,which also had larger tube diameter and several fringes and fractures than other kinds of CNT.The element analysis and the functional group test showed that the elements of O and N had successfully doped into the structures of CNT with uniform distribution,and various chemical bonds and functional groups with N element were grafted on the CNT.Based on the above-mentioned results,the optimized preparation condition of the EPD fabrication method was used to fabricate the electrodes to conduct the electrochemical tests and the saturation adsorption experiments.The specific capacitance?231.89F/g?and the specific adsorption capacity?95.16mg/g?of H/N-O-CNT electrode were 9.5 and 5.9times those of the pristine CNT electrode,respectively,and with lower ion transport resistance.Besides,to be the importantfactor,the hydrothermal reaction temperature was investigated,the result was the optimal hydrothermal reaction temperature of180?.In conclusion,heteroatom doping is an effective means to improve the desalination performance of CDI electrode which can be valuable on academic and application of capacitive deionization technology.