科研之友
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摘要
Ceramic hollow fibers from natural dolomite with different pore structures have been designed. The unique hollow fibers were produced by the phase inversion method and applying different sintering temperatures. The hollow fiber precursor presented coagulated polymers through the fiber thickness due to the high granulometric size of the used dolomite material (11.3-47.2 mu m). The fiber sintered at 400 degrees C presented mechanical strength of 4.5 MPa and water permeability of 84.7 L h(-1) M-2 kPa(-1). The increase in the sintering temperature up to 1250 degrees C resulted in fragile hollow fibers due to dolomite transformations that resulted in gas release and a significant mass loss of 33.7%. At 1350 degrees C, the liquid phase sintering mechanism occurred and the dolomite hollow fiber sintered at 1350 degrees C presented mechanical strength of 5.5 MPa and water permeability of 2219 L h(-1) M-2 kPa(-1). Doloma dissolution in water was investigated and calcium concentration was increased from 0.72 (pure water) to 2.905 ppm for a contact time from 4 h between the fiber sintered at 1250 degrees C and pure water. However, this dissolution did not decrease the mechanical resistance of the fiber. These results suggest the potential of applying natural dolomite for producing low cost membranes or substrates. The hollow fiber sintered at 400 degrees C is suggested to be used as a proper separation medium, while the hollow fiber sintered at 1350 degrees C may be used as a substrate for the deposition of a separation layer to be used in gas separations. The high porosity of the fiber sintered at 1250 degrees C suggests its application as a support for the impregnation of functional materials. Thus, depending on the applied sintering temperature the dolomite membrane can be used in different applications.
- 出版日期2017-12-15
