Preparation Of Polypyrrole Composite Nano-electrode And Its Adsorption Of Metal Ions

Capacitive deionization(CDI)is a new technology for treating heavy metal wastewater.It has the advantages of simple operation,energy saving,recyclable resources,no secondary pollution and good cycle stability.The core technology is the electrode with high adsorption performance.The development of CDI technology so far,the electrode forming process depends on the adhesive problem remains unresolved.This paper focuses on the preparation of carbon nanotube/conducting polymer nanocomposite electrode.The chitosan is added to improve the forming effect of the nanocomposite electrode.The electrosorption effect is also discussed.This thesis mainly includes the following contents:(1)PPy/CS/CNT nano-composites were prepared by in-situ polymerization.The effect of CS addition on the electrochemical performance and adsorption performance of composite nano-electrodes was studied.The morphology,structure and compressive strength of the composite nano-electrodes were characterized.The results show: CS and PPy were sequentially wrapped on the surface of the CNT to form a "one core double shell" structure.The composite nanomaterials showed a nanowire structure and interwoven with each other.When m CS:m Py=2:10,the maximum specific capacitance of PPy/CS/CNT composite nano-electrodes was 103.19F/g,which was 1.6 times of that of PPy/CNT composite nano-electrodes.Under this ratio,the adsorption quantity reaches the maximum of 16.63mg/g,which is 2.1 times of that of PPy/CNT composite nano-electrodes.In the 100 th cyclic voltammetry test,the specific capacitance retention rate was 86.9%,showing good cycle stability.(2)PPy/GO/CS/CNT nano-composites were prepared by in-situ polymerization.The effect of GO addition on the electrochemical performance and adsorption performance of composite nano-electrodes was studied.The morphology,structure and compressive strength of the composite nano-electrodes were characterized.The conclusions are as follows: CNT,CS and PPy,still form a "one core double shell" nanowire structure,which is attached to the GO folds.When m GO:m Py=4:10,the maximum specific capacitance was 223.98F/g,which was 2.2 times of that of PPy/CS/CNT composite nano-electrodes.Under this ratio,the adsorption quantity reached the maximum of 28.29mg/g,which was 1.5 times of that of PPy/CS/CNT composite nano-electrodes.In the 100 th cyclic voltammetry test,the specific capacitance was 90.6%,cycle stability improved.(3)The PPy/CS/CNT and PPy/GO/CS/CNT composite nano-electrodes were applied to CDI process to adsorb and remove heavy metal ions.The effects of initial ion concentration,electrode voltage and ion species on the adsorption performance were investigated,And the adsorption results were kinetic fitting.The results show: For these two kinds of composite nano-electrodes,the adsorption quantity of Cu2+ increased with the increase of the initial concentration of the solution,but the adsorption rate decreased.This shows that they are suitable for the treatment of low concentrations of copper-containing wastewater.Increasing the voltage favors the occurrence of adsorption.The adsorption capacity of these two kinds of composite nano-electrodes to different metal ions is as follows: Fe3+>Cu2+>Ag+.The results of kinetic fitting show that the adsorption of heavy metal ions by these two kinds of composite nano-electrodes is more consistent with Lagergren's second-order equation model,from which the adsorption method is chemical adsorption.