Preparation Of Functionalized Zeolite Imidazolate Framework And Polymer Foam Composites And Their Oil-Water Separation Properties

The main pollutants in petroleum wastewater are generally hydrocarbon compounds and soluble organic and inorganic components,which can cause serious harm to soil surface,rivers and even human body.Traditional domestic petroleum wastewater treatment methods often have defects such as high material density,limited adsorption capacity,high cost,difficult regeneration,and easy secondary pollution when dealing with oil slicks and dispersed oil in petroleum wastewater.In order to solve the above problems,adsorption has become one of the oil-water separation technologies with relatively good practicability.However,most of these adsorption materials are harmful to the environment and are difficult to recycle.Therefore,it is still necessary to develop new environmentally friendly adsorption materials.Metal-organic framework materials have high stability in water,methanol and other solutions,and the framework structure can be adjusted as needed.Therefore,metal-organic framework materials and their composites are potential oil-water separation materials,which can be used to prepare new adsorbents or absorbent material.Based on this,this paper selected different ZIFs materials for oil-water separation experiments,and designed two composite sponges for oil-water separation.The samples were characterized by XRD,SEM,BET and other methods.The oil adsorption capacity was tested,and the effects of compound methods and imidazole content on the phase,microscopic morphology,and oil-water separation performance were explored.The main findings of this paper are as follows:(1)Three different ZIFs materials,ZIF-8,ZIF-67 and ZIF-7,were prepared by co-precipitation method,and the effects of transition metal species and imidazole type on the morphology and size of the products were analyzed.At the same time,according to the BET results,the synthesized ZIF-8 and ZIF-67 showed the I-type adsorption isotherm with microporous characteristics,while ZIF-7 was closer to the IV-type adsorption isotherm with mesoporous characteristics.Through the comparison of oil-water separation performance,it is found that the three ZIFs have oil-water separation performance and the adsorption process is more in line with the pseudo-first-order kinetic model.Therefore,ZIF-8 was finally selected for subsequent composite modification experiments based on the oil-water separation performance.(2)GO with a high degree of oxidation and complete structure was successfully prepared by the modified Hummers method,and ZIF-8/GO microsphere composite was prepared by changing the order of ZIF-8,GO,and PU compounding,and whether it underwent high-temperature thermal reduction.Two different composite materials,sponge and ZIF-8/r GO/PU layered composite sponge.The types and distribution of surface attachments of the two different composite materials were analyzed by XRD and SEM results,and it was found that a layer of r GO and a large number of ZIF-8 microparticles were uniformly distributed on the surface of the ZIF-8/r GO/PU layered composite sponge.Embedded on it,the exposed sponge can hardly be seen,which lays the foundation for the subsequent oil-water separation experiments.(3)The wetting angle of the composite sponge modified by the two methods increases and exceeds 90 °,especially the ZIF-8/r GO/PU layered composite sponge reaches 113 °,showing good hydrophobicity.On the one hand,the wetting angle to oil of both is 0 °,showing super-lipophilicity,while the wettability of the untreated PU sponge to water and oil is hydrophilic and lipophilic.No matter what kind of composite method is used to prepare the sponge,oil-water separation can be carried out continuously,and it has good separation efficiency and good cycle performance.The oil-water separation efficiency of ZIF-8/r GO/PU layered composite sponge can reach 99.75%.The highest adsorption capacity was 48.50 g/g,and the high adsorption capacity could still be maintained after 20 cycles.(4)In terms of Zn:imidazole:GO ratio,with the increase of imidazole content,for the oil-water separation performance of ZIF-8/r GO/PU layered composite sponge,the overall oil absorption showed a trend of first decrease and then increase,while The oil absorption capacity of the ZIF-8/GO microsphere composite sponge has been decreasing;in terms of cycle performance,regardless of the change of imidazole content,when the cycle times increased to 20 times,the adsorption capacity decreased to a certain extent.