MODELING OF ACTIVATED CARBON AND COAL GASIFICATION CHAR ADSORBENTS IN SINGLE-SOLUTE AND BISOLUTE SYSTEMS

A mathemat ical model o f f ixed-bed a d s o r p t i o n was used t o p r e d i c t t h e bed response t o a s u s t a i n e d s t e p change i n i n f l u e n t c o n c e n t r a t i o n . The model was employed t o compare t h e performance o f d i f f e r e n t a d s o r b e n t s i n t h e removal o f o r g a n i c s from w a t e r and t o a n a l y z e f a c t o r s t h a t a f f e c t d e s o r p t i o n owing t o a d e c r e a s e i n i n f l u e n t c o n c e n t r a t i o n and t o c o m p e t i t i v e a d s o r p t i o n . Model e q u a t i o n s , which c o n s i d e r e d t h a t f i l m t r a n s f e r and s u r f a c e d i f f u s i o n c o n t r o l l e d t h e a d s o r p t i o n r a t e , were s o l v e d w i t h t h e t e c h n i q u e o f o r t h o g o n a l c o l l o c a t i o n . Three s p e c i e s , 3,5-dimethylphenol (DMP), 3 ,5-dichlorophenol (DCP) and rhodamine 6G (R6G), were t h e s i n g l e s o l u t e s s t u d i e d , and t h e two phenols were a l s o examined as a mixture . Four a c t i v a t e d ca rbons and a c o a l g a s i f i c a t i o n c h a r were t h e a d s o r b e n t s s t u d i e d . The model was used t o compare t h e a d s o r b e n t s i n . t h e removal o f DMP, R6G and t h e b i s o l u t e m i x t u r e s and e q u i l i b r i u m c a p a c i t y was found t o have a g r e a t e r i n f l u e n c e t h a n k i n e t i c s on fixed-bed performance. It was observed t h a t , under c o n d i t i o n s approximat ing a d r i n k i n g w a t e r p l a n t , t h e t i m e d u r i n g which t h e e f f l u e n t c o n c e n t r a t i o n of a desorbed s p e c i e s was h i g h e r t h a n t h e i n f l u e n t c o n c e n t r a t i o n was s i g n i f i c a n t (on t h e o r d e r o f weeks) whether a reduced i n f l u e n t c o n c e n t r a t i o n o r compet i t ion was r e s p o n s i b l e f o r t h e d e s o r p t i o n . Thacker, W i l l i a m E., Snoeyink, Vernon L., and C r i t t e n d e n , John C . , MODELING OF ACTIVATED CARBON AND COAL GASIFICATION CHAR ADSORBENTS I N SINGLESOLUTE AND BISOLUTE SYSTEMS, Research Report No. 161 , Water Resources Cen te r , U n i v e r s i t y o f I l l i n o i s a t Urbana-Champaign, J u l y 1981.