Modification Of Copper-nickel Foam Electrodes And Their Electrosorption/degradation Of Organic Pollutants

Electrochemical water treatment technology,as a new clean treatment process,is gradually applied in the field of wastewater treatment.It has the advantages of high efficiency,flexible reaction,strong controllability,no secondary pollution,simple device,small floor area,flexible process and wide application range.Among them,electrochemical water treatment technology has great advantages for the removal of refractory organic pollutants in organic wastewater.The research and development of electrode materials is the key to the efficient treatment of pollutants by electrochemical technology.In order to solve the disadvantages of electrode materials in the current electrochemical water treatment technology,such as high resistance,high price or complex modification experiment,this study focuses on the research and development of new electrode materials with low cost,high efficiency,simple preparation method,high chemical stability and renewable recycling,which can be applied to electrosorption and degradation of organic pollutants.The details are as follows:（1）A three-dimensional porous copper-nickel foam electrode（CNF）was prepared by a simple constant current electrodeposition method,Scanning electron microscopy（SEM）and X-ray diffraction（XRD）were used to analyze the phase and electrochemical characterization analysis,and using 4-chlorophenol（4-CP）as the target pollutant,the electrosorption behavior of 4-CP on the electrode was studied.The effects of polarization potential,initial pH value of the solution,and electrolyte concentration on the adsorption effect were analyzed,and the electrosorption kinetics and thermodynamics of the adsorption process were studied.The results showed that when the initial concentration of 4-CP was 20 mg / L,the pH was 2.5,the electrolyte concentration was 0.1 M,and the polarization potential was-0.5 V,the removal rate of 4-CP by the CNF electrode reached 92.12%.The electrosorption process was more consistent with the Lagergren second-order kinetic model adsorption isotherm and is more in line with the Langmuir isotherm;the maximum adsorption capacity（q_m）was 598.8 mg/g.（2）The Pd@CNF electrode was successfully prepared by loading palladium nanoparticles on the CNF electrode by a simple pulse electrodeposition method.The phase of the electrode was characterized by SEM,XRD,EDS and mapping.The electrode was electrochemically characterized by EIS.And the dechlorination efficiency of 4-CP on Pd@CNF electrode was studied.The Pd@CNF retains the highly branched dendrite structure and abundant pore channels of CNF electrode.These dendrites with spatial ductility can increase the specific surface area of the electrode,provide more pollutant adsorption sites and catalytic active sites,which is conducive to the full utilization of catalyst and promote the electrocatalytic reduction and dechlorination of 4-CP by the electrode.When the initial concentration of 4-CP is 100 mg/L,pH value is 2.5,cathodic potential is-1.2 V,and Na₂SO₄concentration is 0.10 M,the dechlorination efficiency is 92.32% after 120 min.The removal behavior of 4-CP on Pd@CNF electrode was studied.It was found that the main product of catalytic dechlorination is phenol.The dechlorination process follows the first-order reaction kinetics.The reaction rate constant k is 0.0195 min^-1,R² = 0.994.Pd@CNF electrode has good cycle stability,and the dechlorination efficiency of the electrode can still be maintained above 85.52% after repeated 7 cycles under the same experimental conditions.（3）GO-PPy @ CNF composite electrode was prepared by electrochemical coprecipitation of go and PPy on CNF substrate in a simple one-step method.The phase analysis and electrochemical behavior analysis of the electrode surface were carried out by various characterization methods.Rhodamine B（RhB）was used as the target pollutant to study its electrosorption behavior on the electrode.The results show that the composite electrode has a porous and interconnected nanodendrite structure,and there are abundant functional groups on GO-PPy,which is very ideal for improving the electrical adsorption performance of RHB.Compared with the CNF electrode,under the optimal conditions: the initial concentration of RhB is 20 mg/L,pH is 7.5,Na₂SO₄ concentration is 0.10 M,and the polarization potential is-1.0 V,the composite GO-PPy @ CNF shows higher adsorption capacity（increased 175.7%）and higher adsorption rate（increased 468.8%）for RhB.It is found that Langmuir isotherm model can well describe the electrosorption process,which follows pseudo second-order kinetics.In addition,based on the Weber Morris model,both the membrane diffusion and the intra particle diffusion are involved in the control of the rate of electrosorption.In conclusion,three-dimensional CNF and its modified electrode were prepared by simple operation in order to achieve the purpose of efficient removal of pollutants.The open growth of CNF with interconnected dendrites increases its specific surface area and porosity,which makes it a potential matrix material for supported catalysts.The purpose of this study is to promote the development and application of low-cost and high-efficiency CNF and its modified materials in the field of water pollution control.