Characteristics of nonafluorobutyl methyl ether (NFE) adsorption onto activated carbon fibers and different-size-activated carbon particles

The characteristics of adsorption of 1,1,1,2,2,3,3,4,4-nonafluorobutyl meth yl ether (NFE), a chlorofluorocarbon (CFC) replacement, onto six different activated carbon; preparations (three activated carbon fibers and three dif ferent-sized activated carbon particles) were investigated to evaluate the interaction between activated carbon surfaces and NFE. The amount of NFE ad sorbed onto the three activated carbon fibers increased with increasing spe cific surface area and pore volume. The amount of NFE adsorbed onto the thr ee different-sized-activated carbon particles increased with an increase in the particle diameter of the granular activated carbon. The differential h eat of the NFE adsorption onto three activated carbon fibers depended on th e porosity structure of the activated carbon fibers. The adsorption rate of NEE was also investigated in order to evaluate the efficiency of NFE recov ery by the activated carbon surface. The Sameshima equation was used to obt ain the isotherms of NFE adsorption onto the activated carbon fibers and di fferent-sized-activated carbon particles. The rate constant k for NFE adsor ption onto activated carbon fibers was larger for increased specific surfac e area and pore volume. The rate of NFE adsorption on activated carbons of three different particle sizes decreased with increasing particle diameter at a low initial pressure. The adsorption isotherms of NFE for the six acti vated carbons conformed to the Dubinin-Radushkevich equation; the constants BE0 (the affinity between adsorbate and adsorbent) and W-0 (the adsorption capacity) were calculated. These results indicated that the interaction be tween the activated carbon and NFE was larger with the smaller specific sur face area of the activated carbon fibers and with the smaller particle diam eter of the different-sized-activated carbon particles. The degree of packi ng of NFE in the pores of the activated carbon fibers was greater than that in the pores of the granular activated carbons. (C) 2000 Academic Press.