| Ion exchange membrane is a kind of functional polymer membrane with ion selection and permeability,which has a wide range of applications in chemical production,food processing,drug purification,energy savings,wastewater treatment and other fields.The application of ion exchange membrane separation technology has the characteristics of convenient and efficient operation,saving energy resources and no secondary pollution.It is especially suitable for the needs of energy saving,reuse of low grade raw materials and elimination of environmental pollution in modern industrial production.The application of ion exchange membrane separation technology in the field of membrane cobalt electrodeposition or cobalt electrodeposition wastewater treatment can not only purify and recover high quality cobalt metal simple matter,but also avoid the production of harmful gas chlorine gas.And it can also produce recyclable hydrochloric acid,which basically does not produce any secondary pollution,but the application and popularization of this new technology put forward high requirements for the performance of ion exchange membrane.In particular,the chloride ion barrier performance and acid and oxidation resistance of cationic exchange membranes are high.However,the chloride ion barrier properties of most commercial ion exchange membranes produced at home and abroad are generally not very high.The acid resistance and oxidation resistance are also very limited,which seriously limits the development and application of this new technology.Therefore,this paper decides to take the preparation of organic-inorganic ion hybrid ion membrane as a breakthrough,and choose the film forming performance as the breakthrough point.Organic and inorganic materials with good physicochemical stability,combined with the related research and preparation technology in this field,an organic-inorganic hybrid ion exchange membrane with potential application in membrane cobalt electrodeposition process has been developed.In this paper,polyvinylidene fluoride(PVDF),which has excellent film forming performance and good physicochemical stability,was used to prepare hybrid ions.The organic polymer membrane framework of the membrane is composed of phosphotungstic acid(PWA)and zirconium phosphate(ZrP),which have high surface charge,excellent acid and oxidation resistance,and zirconium phosphate,which are the charge groups of the hybrid ion membrane.Firstly,phosphotungstic acid and zirconium phosphate particles were introduced into the parent of poly(vinylidene fluoride)membrane by direct blending method,and the PWA/PVDF hybrid ion membrane and ZrP/PVDF hybrid ion membrane were prepared.The basic properties of polymer-based hybrid ion membranes were characterized,the chloride ion barrier and strong acid and strong oxidation properties of the membranes were tested,and the surface and cross-section micromorphology of the membranes were analyzed by SEM.Andthen On the basis of the preliminary preparation and performance study of PWA/PVDF hybrid ion membrane,it was improved by means of effective fixation of phosphotungstic acid and hot pressing treatment of the membrane.The optimum preparation conditions and basic properties of the membrane were studied experimentally.The chloride ion barrier and acid resistance and oxidation resistance of the membrane were tested.The surface and cross-section morphology of the membrane were analyzed by SEM,and the functional group type and interaction in the membrane were analyzed by FRIT.Finally,on the basis of the preliminary preparation and performance study of ZrP / PVDF hybrid ion membrane,the direct synthesis of zirconium phosphate in the membrane by in-situ reaction was carried out.The optimum preparation conditions and basic properties of the membrane were studied.The chloride ion barrier and acid resistance and oxidation resistance of the membrane were tested.The surface and cross-section micromorphology of the membrane were analyzed by SEM.The type and interaction of functional groups in the membrane were analyzed by FRIT.The results show that the initial PWA/PVDF hybrid ion membrane has a relatively high number of counter-ion migration and a relatively low leakage rate of chloride ion,but under the long-term action of strengthening the electric field,the initial membrane has a relatively high number of counter-ion migration and a relatively low leakage rate of chloride ion.The ion exchange capacity of the membrane will be seriously lost,and the leakage rate of chloride ion will be greatly increased,which is due to the instability of phosphotungstic acid particles in the membrane.After improving the preparation of PWA/PVDF hybrid ion exchange membrane,the ion exchange capacity of the membrane was increased to 1.19 mmol / kg,the counter ion migration number of the membrane was increased to 0.94,the leakage rate of chloride ion was decreased to 7.5%,and the ion exchange capacity of the membrane was increased to 1.19 mmol / kg,and the leakage rate of chloride ion was decreased to 7.5%.Long-term electrolysis under the external strengthening electric field can basically maintain about 8.2%.Compared with the PWA/PVDF hybrid ion membrane,the chloride ion barrier performance of the membrane is higher and more stable,and the acid and oxidation resistance of the membrane is better than that of the initial preparation of PVC hybrid ion membrane.In the preliminary preparation of ZrP/PVDF hybrid ion membrane,the reverse ion migration number is relatively low and the leakage rate of chloride ion is relatively high at the beginning of the membrane,and the ion exchange capacity of the membrane will be partially lost under the long-term action of strengthening the electric field.The leakage rate of chloride ion will be further increased because of the uneven distribution and immobilization of zirconium phosphate particles in the membrane,through the heterosis of ZrP/PVDF The ion exchange capacity of the membrane was increased to 1.05 mmol/g,and the leakage rate of chloride ion was reduced to 7.4%.The ion exchange capacity of the membrane was increased to 0.93%,and the leakage rate of chloride ion in the membrane was reduced to 7.4%.The ion exchangecapacity of the membrane was increased to 0.93% and the leakage rate was reduced to 7.4%.Compared with the ZrP/PVDF hybrid ion membrane,the chloride ion barrier performance of the membrane is higher and more stable,and the acid resistance and oxidation resistance of the membrane are good.Compared with the improved PWA/PVDF hybrid ion membrane and the ZrP/PVDF hybrid ion membrane,the preparation process of ZrP/PVDF hybrid ion membrane is relatively simple.The preparation cost is relatively low,and it has the potential to be used in the process of cobalt electrodeposition by membrane method. |
