The Preparation And Property Of Zirconia Hollow Fiber Membrane And Zirconia/carbon Composite Membrane

Ceramic hollow fiber membranes(HFMs)can be applied in gas-liquid separation,water desalination and sewage treatment under the condition of high temperature,high pressure and corrosiveness environment,due to the characteristics of high strength,thermal stability,excellent chemical corrosion resistance,large effective separation area and washability.In order to resist the complex stress and strain during assembly and cleaning,the ceramic HFMs need to balance permeability,separation performance and mechanical properties.In this study,in situ carbon was formed in yttria-stabilized zirconia(YSZ)HFMs,which improved the absorption performance without significant effect on mechanical properties and permeability.This research provides a reference for fabrication and application of YSZ-C HFMs.Firstly,ceramic HFMs precursor with asymmetric structure was one-step prepared by phase inversion/(dry-wet spinning method),and then the precursor was sintered in air to obtain YSZ HFMs.The effects of sintering temperature on microstructure and mechanical properties under different loading conditions were investigated.Afterwards,the YSZ-C HFMs were fabricated by vacuum sintering,in which the carbon was in situ formed due to the incomplete pyrolysis.The content and form of carbon can be adjusted by the sintering parameters,and their influence on the mechanical properties of HFMs was further studied.Finally,the pure water flux and iodine adsorption of YSZ and YSZ-C were compared and researched,and relationship between these properties and carbon content was analyzed.The results suggest that the three point bending strength was higher than radial compression strength of the YSZ HFMs.For HFMs sintered at1250°C,the three point bending strength and radial compression strength were 189 MPa and 134 MPa,respectively.During the radial compression test,the crack propagation was affected by the finger-like pores,leading to the more complicated fracture mode.The carbon content can be adjusted by changing the sintering pressure.When the sintering pressure was set as 20 k Pa,the YSZ-C HFMs with the carbon content of 0.09-0.18 wt.%had a stable mechanical properties with the bending strength higher than 150 MPa.The bending strength of the YSZ-C HFMs increased from 178MPa at 1300°C to 311 MPa at 1400°C.The sintering temperature had an effect on the form of carbon in the HFMs.The ratio of amorphous carbon and Zr O_xC_y changed from 11:1 at 1300°C to 6:5 at 1400°C.The pore size of small pores in the YSZ-C HFMs was lower than that in the YSZ HFMs with the same total porosity,which resulted in a lower pure water flux of the former.However,due to the higher specific surface area of the small pores,the iodine adsorption of the YSZ-C HFMs was 6to 10 times that of the YSZ HFMs.