| Title |
Chemical and / or Thermal Regeneration of GAC and Adsorption Characteristics of Regenerated GAC : 2 . Anoxic Condition and Effect of Dissolved Natural Organic Matter |
| Authors |
한인섭(Ihn Sup Han),조용균(Yong Kyun Cho) |
| Abstract |
Preloaded GAC with phenol and HA and virgin GAC were used for investigating the change of adsorption capacities and the effects of DO and NOM. The experiments were conducted at pH 7 and 23±1℃ under the anoxic condition. All the experimental procedures for anoxic experiments were performed in an anaerobic chamber except tumbling the samples. Specifically, preloaded GAC with HA under the anoxic condition was used for the oxic and anoxic adsorption experiments after regeneration by thermal or chemical methods. i) Adsorption of phenol and DNT with virgin GAC Freundlich isotherm equations were q_e=23.8C_e^(1/0.420) and q_e=119.5C_e^(1/0.274) for phenol and DNT, respectively, whose adsorption capacities were smaller than those of the oxic experiment. It was observed that adsorption capacity for phenol decreased more than that for DNT depending on the presence/absence of DO. It was possibly due to transformation (or oxidative coupling(s)) reactions) on the GAC surface in the presence of DO. To get the equilibrium between liquid and solid phases, it required one week or shorter and the trend observed in the oxic experiments that the longer contact time, the less extraction efficiencies, was not shown. ii) Adsorption of phenol and DNT with preloaded GAC. Depending on the regeneration methods and preloading compounds, the differences of adsorption capacities were observed. Regenerated GAC after preloading with phenol showed approximately 10 to 20% decrease in adsorption capacities for phenol and 5 to 15% decrease for DNT. Adsorption capacity was larger after thermal regeneration, especially for HA-polluted GAC. Re-adsorption capacity (that is, adsorption capacity after regeneration) was greatly affected by the preloading materials. |