Abstract
Activated carbon/TiO2 composites were synthesized for the removal of 1,4-dioxane in landfill leachate. The composites had photocatalytic activity and almost equivalent adsorption capacity to that of woody activated carbon used for the synthesis, and 1,4-dioxane in pure water was simultaneously adsorbed and decomposed by the composites. As a result of evaluating inhibitory effect of coexistent substances such as inorganic ions and dissolved organic matters, it was clarified that chloride inhibited photocatalysis and humic acid reduced the rate of adsorption and photocatalytic decomposition. Although the simultaneous removal of 1,4-dioxane and dissolved organic matters in biologically treated landfill leachate was accomplished by using the composites, coexistent substances strongly inhibited the photocatalytic decomposition of 1,4-dioxane. Therefore, the authors proposed a sequential treatment process, adsorption followed by decomposition. They realized reduction of 1,4-dioxane in the leachate to less than the effluent standard value and the regeneration of the composites by photocatalytic decomposition of 1,4-dioxane.
