| Popis: |
In-situ regeneration of spent activated carbon can be a more cost effective alternative than the thermal regeneration method. This paper studies the suitability of ethanol for the regeneration of a granular activated carbon (Filtrasorb-400), that was saturated with phenol from wastewater. Ethanol is less hazardous, completely miscible with water and offers convenient solvent recovery. The adsorption capacity of fresh activated carbon for phenol was found to be 208 mg g−1. The recovery of phenol adsorption capacity of the carbon, operated cyclically using a sequence of phenol adsorption, desorption with ethanol, and rinsing with water, was determined in both batch and fixed-bed processes. The kinetics of the regeneration process were also studied. In the fixed-bed process, the regeneration efficiency by using ethanol was 98% after the first regeneration cycle and 94% after the third regeneration cycle. The corresponding values for batch operations were 89% and 85%, respectively. The kinetics of regeneration in batch processes were fast, and 90% of the total regeneration was complete within 30 minutes. The results from this study indicate that ethanol could be used to regenerate granular activated carbon in-situ with only marginal loss of adsorption capacity. |
