PREPARATION AND CHARACTERIZATION OF CATION-EXCHANGER USING MESO-CARBON MICROBEADS PREPARED BY EMULSION METHOD

The reactivity toward sulfonation and ion-exchange capacity of meso-carbon microbeads were investigated. The meso-carbon microbeads (coal and petroleum based) prepared by an "emulsion method" were sulfonated by concentrated sulfuric acid at 0-50°C for 30-300 min. To prevent the particles from breakage, a heat treatment at 500°C was necessary. The results of FTIR spectra indicated that sulfonation and oxidation occurred simultaneously. Total ion-exchange capacity (strongly and weakly acidic) of MCB increased with the reaction temperature and tended to saturated over 180 min of reaction time. The sulfonated (50°C, 300 min) meso-carbon microbeads had 0.51 (coal based) and 0.79 (petroleum based) milliequiv./g of weakly acidic ion-exchange capacity, and had 0.39 and 0.74 meq./g of weakly acidic ion-exchange capacity due to oxidation by thermosetting process and sulfonation. The petroleum based microbeads indicated stronger activity for sulfonation and slower ion-exchange rate than the coal based one. The strongly acidic ion-exchange capacity decreased at temperatures between 220 and 300°C because of decomposition of sulfonic acid group. © 1990.