Synthesis and Characterization of Porous Ceramic Hollow Fibers with Nano-Molecular Size

This research exhibits a method for the fabrication of nano molecular size ceramicporous hollow fibers, using the internal diffusion technique. This method is based onpreparation a spinning solution consists from nano gamma alumina < 50nm in an aqueousmixture of sodium alginate, and calcium carbonate. The mixture is spun into a lactic acidcoagulation bath of pH= 1.6 to achieve ionic cross-linking. The green transparent ceramichollow fibers were dried under ventilation at ambient temperature for 48h and sintered atdifferent temperatures 1100 oC-1350 oC for 2h. The synthesized fibers were characterizedand the effect of sintering temperature on surface morphology was studied. The phasetransformation from gamma to alpha was specified by x-ray diffraction, at 1100 oC a fewsmall and sharp peaks of α-alumina started while at 1250 oC α-alumina with a highlycrystalline structure was obtained. Microstructure and surface morphology of nano ceramicfibers were studied at different sintering temperatures, a homogeneous particle distributionwas gained at a temperature of 1250 oC. The thermal gravimetric analysis was referred toan existence of two thermal steps occurred during thermal treatment, dehydration up to 250oC and alginate dehydration and decomposition from 250 oC to 400 oC. The nitrogenisotherm behavior indicates to a mesoporous / macroporous substance, an appearance oftype H-2 hysteresis loop. BJH adsorption and desorption average pore diameter (4V/A)14.4408 nm and 17.7124 nm respectively. Single point surface area is 9.268 m²/g, singlepoint adsorption total pore volume is 0.023 cm³/g. The average interior and exterior poresize by mercury intrusion were 20 nm and 50 nm respectively.