REGENERATION OF AN ACTIVATED CARBON BED EXHAUSTED BY INDUSTRIAL PHENOLIC WASTE-WATER

The main objective of this study is the regeneration of an activated c arbon bed exhausted by industrial phenolic wastewater. The regeneratio n of activated carbon beds is carried out before proceeding with the n ext exhaustion stage. The liquid retained in the column is rinsed out with water and solutions of sodium bicarbonate 1N and, subsequently, s odium hydroxide 1.5N are used to regenerate the beds.The column is cle ansed with water. A solution of sulfuric acid 0.5N is added, and then water, until a pH of less than 3 is reached. After this treatment proc ess, the columns are ready for the adsorption stage of the next cycle of adsorption-regeneration. pH variations of the solution of each colu mn and the concentration of the analyzed components, phenol, salicylic acid, bhydroxybenzoic acid and 4-hydroxyisophthalic acid are taken as time passes. A maximum concentration of salicylic acid and 4-hydroxyi sophthalic acid with approximately pH 6.5 is observed. 4-Hydroxybenzoi c acid is desorbed mostly between pH 9 and 10. The maximum phenol conc entration appears at a pH of around 12. It is shown that the largest q uantity of 4-hydroxybenzoic acid and the second highest concentration of salycilic acid are produced by the effect of the carbonates.