REMOVAL OF CHLORINATED PHENOLS FROM AQUEOUS-SOLUTIONS BY ADSORPTION ON ALUMINA PILLARED CLAYS AND MESOPOROUS ALUMINA ALUMINUM PHOSPHATES

Alumina pillared montmorillonite (AIPMt) and mesoporous alumina alumin um phosphates (AAPs) were contacted with aqueous, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol solutions, at a concentrat ion range between 25 and 250 mu g/litre, in batch equilibrium experime nts, in order to determine their adsorption properties. The removal of chlorophenols by the adsorbents increase with increasing chlorine sub stitution in their molecules. In the case of pentachlorophenol, the in creased affinity allows adsorption to occur much more efficiently than in the case of other compounds. AIPMt material adsorbs 26.3% of 2,4-d ichlorophenol, 75.6% of 2,4,6-trichlorophenol and 95.2% of pentachloro phenol at equilibrium. The adsorption of chlorophenols on mesoporous A APs is much less pronounced as compared to clays but increases with th e ratio of P/Al, as the surface acidity of those solids also increases . The AAP mixture with a ratio P/Al = 0.6 adsorbs 14.8% of 2,4-dichlor ophenol, 27.1% of 2,4,6-trichlorophenol and 58.3% of pentachlorophenol . The amounts of chlorophenols decomposed during the treatment increas e in AAPs Ind especially in those with a higher P/Al ratio (= 0.6). (C ) 1998 Elsevier Science Ltd. All rights reserved.