Study Of Activated Carbon Adsorption For Phenol And Its Regeneration

Activated carbon which was exhausted by phenol was regenerated by Fenton oxidation, iron-carbon micro-electrolysis and micro-electrolysis coupled with Fenton process. Adsorption and thermodynamic properties of fresh and regenerated carbon were analyzed by adsorption efficiency test and adsorption isotherm test, respectively. Process of regeneration was characterised by Elovich, first order kinetics and second order kinetics equation to study the affecting factors and character of regenerating reaction.The results showed that fresh activated carbon had a good adsorption capacity for phenol. The adsorbance of fresh activated carbon was 9.60 mg·g^-1 and the adsorption was a spontaneous exothermic process, moreover,the adsorbance decreasd with temperature increasing.The activation energy of adsorption ,which have been a chemisorption process,was 31.42KJ·mol^-1.The adsorption capacity for phenol of activated carbon which was regenerated in the ways of Fenton, micro-electrolysis and micro-electrolysis coupled with Fenton oxidation was 7.97mg·g^-1, 4.56 mg·g^-1 and 8.27mg·g^-1, respectively.Regeneration efficiency of the three kinds of process was 82.96 %, 47.49% and 86.13%.Adsorption isotherm test of regenerated carbon displayed that carbon regenerated by micro-electrolysis coupled with Fenton oxidation and Fenton oxidation process have a good adsorption capacity for phenol, whose adsorption and thermodynamic properties were closer to fresh activated carbon, and the adsorption properties of micro-electrolytic regenerative carbons had changed to some extent. Modeling results of kinetics of the regeneration process revealed that Fenton regeneration was mainly consistent with the second orde kinetics equation of desorption,because phenol was desorbed into water firstly,and then oxidated by Fenton reagent.Regeneration processes of micro-electrolysis were very complex and in accordance with Elovich model. Elovich model and second order kinetic model of regenerating process using micro-electrolysis coupled with Fenton oxidation both possessed good correlation, indicating that the process of regenerating activated carbon using micro-electrolysis coupled with Fenton oxidation was very complex, involving electrolysis, Fenton reaction and phenol desorption.