EFFECT OF NANOPORE SIZE DISTRIBUTIONS ON TRICHLOROETHYLENE ADSORPTIONAND DESORPTION ON CARBOGENIC ADSORBENTS

Two carbon adsorbents, Ambersorb-600 and Ambersorb-563 (A-600 and A-56 3), were compared for vapor-phase trichloroethylene (TCE) adsorption f rom humid air streams. These adsorbents retained capacity for TCE in h umid environments and were regenerable in situ. Enhanced desorption, a nd hence, increased working capacities, were achieved with bimodal por e size distributions and hydrophobic surface chemistry. Vapor-phase TC E isotherms confirmed that both of these adsorbents have high capaciti es for TCE. Only a small difference between the micropore size distrib utions of A-563 and A-600 was determined by room-temperature methyl ch loride adsorption and the modified Horvath-Kawazoe model. Besides diff erences in particle size and pore volume there was a measurable, but s mall change, in the fraction of the pores in the ultramicropore range (5 Angstrom or smaller) of the A-600 adsorbent versus that of A-563. I n packed-bed breakthrough curve experiments, A-600 displayed a sharper mass-transfer zone than A-563, but maintained essentially the same ca pacity for TCE in a humid environment. Both materials were amenable to in-situ regeneration, and the A-600 a provided higher overall working capacity than that of A-563.