Research On The Preparation Of Multi-porous Titanium Film By Dealloying Method And Its Electrochemical And Electrocatalytic Properties

As a novel porous membrane material,titanium membrane has good properties,such as thermal stability,chemical stability,excellent mechanical strength and so on.However its low specific surface area is a difficult problem which should be solved in application process.In this paper,we first prepared hierarcthically porous titanium(Ti)membrane by the method of powder metallurgy and melt metal dealloying and studied the formation mechanism of hierarchical pores.Then,hierarchically porous MnO,/Ti electrocatalytic membrane,prepared by sol-gel method with using hierarchical porous Ti membrane as the basic membrane,was applied to ECMR as an anode to treat Congo red wastewater.The catalytic efficiency of Congo red was as a standard to optimize the preparing parameters of hierarchical porous Ti membrane and the operating parameters of ECMR.According to XRD,The optimum temperature of preparing Cu-Ti phase was 850?.We also analyzed the conversion path of phase in the membrane preparation process,and explained the important role of Mg in the melt metal dealloying.The microstructure of hierarchically porous Ti membrane(hierarchically porous structure)and the element contents(mainly Ti and O)were characterized by SEM and EDX.In order to determine open-pore size distribution of prepared membrane,we used Capillary Flow Porometer and BET to find membrane pore size ranging from 2 nm to 5?m,which showed a hierarchical distribution of membrane pore size.We characterized hierarchically porous Ti membrane by XRD,SEM,BET,electrochemical performance(CV,EIS,CA)and electrocatalytic performance and determined the optimum preparation parameters of membrane.The prepared Ti membrane had the best performance in the condition that:atomic ratio Ti:Cu=75:25,atomic ratio Mg:Cu=70:30,sintering at 850 ?.The membrane property is showed as follow:porosity is 60%,water flux is 4561.75 L/(h·m2-bar),hardness is 28.6 HV,the electrochemical active area is about 0.96 cm2,and the diffusion coefficient is about 1.94×1 0-5 cm2·s-1.When hierarchically porous MnO./Ti electrocatalytic membrane is applied to ECMR,the decolorization rate of Congo red is 99%and the TOC removal rate is about 60%at the condition that:pH is 7.0,temperature is 25 °C,electrolyte concentration of Na2SO4 is 15 g·L-1,Congo red initial concentration is 150 mg·L-1,the current density is 0.35mA·cm-2,and residence time is 12 min.According to decolorization rate and TOC removal rate,we optimized the operating parameters of ECMR which was used to treat Congo red dye wastewater.The optimal parameters are showed as follow:current density is 0.3 mA·cm-2,residence time is 12 min,and initial concentration of Congo Red is 150 mg·L-1.Then,TOC removal rate and decolorization rate of Congo Red could reach 80%and 99%,respectively.