Chemical Regeneration of Exhausted Granular Activated Carbon Used in Citric Acid Fermentation Solution Decoloration

An improved chemical regeneration of the granular activated carbon (gac) exhausted by the color (pigments and pollutants) from citric acid fermentation solution (caf) was investigated. in the experiments, improved means were adopted to advance the traditional chemical regenerating method and the adsorption capacity of the first time renewed gac is 103 % of original gac. using oxidant and surfactant in addition to just using naoh solution can recover 10 % more adsorption capacity of renewed gac. the adding dosage of oxidant is good at 3 % of exhausted gac weight; that of surfactant is good at 0.1 %. hot water as cheap reagent was found to be much helpful to the regeneration efficiency. comparing with steam regeneration high regeneration yield (>95 %) of this method was an attractive economic factor. the result of this investigation can offer an advanced chemical regeneration method to regenerate exhausted gac from citric acid refine industry.