Study On The Performance Of Supported Iron-based Catalytic Hydrolysis Intermediate Layer And Bipolar Membrane

The bipolar membrane consists of an anion exchange layer,a cation exchange layer and an intermediate layer located between the two layers.When a reverse DC voltage is applied to both sides of the bipolar membrane,the water molecules in the middle layer will be hydrolyzed into hydrogen ions and hydroxide ions and diffuse into both sides of the bipolar membrane to form corresponding acids and bases.Therefore,it has a wide range of applications in the preparation of acids and bases.Since the catalytic hydrolysis performance of the intermediate layer is a key factor affecting the performance of the bipolar membrane,modification of the intermediate layer of the bipolar membrane is of great significance to improve the performance of the bipolar membrane.In this work,NaA molecular sieves and FeCl3 are first assembled on the surface of the cation exchange membrane to form an intermediate layer by intermixed liquid spraying method and dipping liquid spraying method,respectively.Further spray assembly of polyethyleneimine,cross-linked with glutaraldehyde to form a new bipolar membrane.The morphology,structure,and thermal stability of the prepared bipolar membrane were investigated in depth,the effects of the compounding method,composition ratio and concentration of NaA molecular sieve and FeCl3 in spraying liquid on the hydrophilicity of the intermediate layer,the voltage drop of the bipolar membrane and the acid and alkali production performance are systematically studied,and the following main conclusions are drawn:(1)The bipolar membrane with FeCl3/NaA molecular sieve composite as the middle layer was prepared by dipping liquid spraying method,and the influence of the composition ratio and concentration of NaA molecular sieve and FeCl2 on the physicochemical properties and electrodialysis performance of the bipolar membrane was studied.When the current density is 100 mA/cm2,the voltage drop is 1.065 V;the rate of acid production and alkali production are 26.74 mol·m-2-h-1 and 11.77 mol·m-2·h-1,respectively.(2)The bipolar membrane with FeCl3/NaA molecular sieve composite loaded on the middle layer was prepared by the intermixed liquid spraying method.When the current density is 100 mA/cm2,the voltage drop is 1.076 V;the acid and alkali production rates are 18.06 mol·m-2·h-1 and 11.09 mol m-2·h1,respectively,and the prepared membrane shows good thermal stability.