Most Suitable Conditions for Regeneration of Activated Carbons which Adsorbed Various Amount of Contaminants from Waste Water of Dye Manufacture

Abstract

The most suitable conditions for the regeration of the granular activated carbons which adsorbed various amount of contaminants containing nitro- or chloro-benzene, toluene and intermediate products of dye were investigated. The spent carbons were heated in pure N₂or in the mixed gases of N₂ and 10% steam or 2% O₂. The pore distributions and the adsorp- tivities of the regenerated carbons were compared with those of the virgin carbon. The suitable conditions are greatly dependent on the adsorbed amount. The spent carbon which adsorbed 15 wt % contaminants was able to regenerate well at 950° in N₂ or at 800° in N₂+10% steam. The spent carbon which adsorbed 20 wt % contaminants was not able to regenrate in N2, but it was able to regenerate at 850° in N₂+10% steam. The spent carbon which adsorbed 26 wt % contaminants was not able to regenerate well under any condition. The pore distributions and the adsorption capacities of the regenerated carbons were able to make equal to those of the virgin carbon. The micropore changes into large pore, and the yield is law at a higher temperature than that at which the suitable conditions are fulfilled.