| Title |
Chemical and / or Thermal Regeneration of GAC and Adsorption Characteristics of Regenerated GAC : 1 . Oxic Condition |
| Authors |
한인섭(Ihn Sup Han),조용균(Yong Kyun Cho) |
| Abstract |
Filtrasorb 400 GAC preloaded with phenol was chemically and thermally regenerated and the regenerated GAC was used for investigation on the change of adsorption capacities. The experiments were carried out at pH 7 and 23±1℃ under the oxic condition. Isotherm, rate and extraction experiments were conducted using virgin GAC and isotherm experiments were using preloaded GAC after regeneration and/or drying. The data obtained from the isotherm experiments were well fitted by Freundlich isotherm. i) Isotherm, rate and extraction for phenol and DNT using virgin GAC Freundlich isotherm equations were q_e=35.8C_e^(1/0.357) and q_e=129.7C_e^(l/0.283) for phenol and DNT, respectively. The adsorption capacity for DNT was larger than that of phenol. It required a longer contact time for phenol to get an equilibrium. probably due to transformation of phenol on the GAC surface in the presence of DO. Extraction efficiencies from GAC for adsorbed phenol were decreased with increasing contact time, but for DNT such a trend was not observed. ii) Isotherm using preloaded GAC and repeatedly regenerated GAC. There existed in difference of adsorption capacities depending on the regeneration method. Thermal regeneration was better than chemical regeneration in the viewpoint of adsorption capacity. The decrease in adsorption capacity for phenol was larger than that for DNT in comparison of the adsorption capacity of virgin GAC. As the contact time increased for preloading, the adsorption capacity for preloaded DNT decreased. Dried GAC after preloading showed a little adsorption capacity, possibly due to the desorption of sorbed phenol by heat during drying. Such trends were double-checked through the results obtained using repeatedly-regenerated GAC. It was possibly explained by the deduction that active adsorption sites for phenol and DNT are different. |