Granular Activated Carbon as Supporter in a FBR-Fenton Reactor：Adsorption, Catalysis and Chemical Oxidation Regeneration
Hydroxyl radical（·OH）is very oxidative, which is the base of advanced oxidation process（AOPs）for degrading organic compounds in water and wastewater. Fenton’s reagent（H2O2/Fe2+）has been proved in a lot of studies to be an effective and simple oxidant, but the drawback is the production of substantial amount of Fe（OH）3 sludge that requires further seperation and disposal. To solve this problem, the application of H2O2 as oxidant and iron oxide as the heterogeneous catalyst in oxidizing organic contaminants deserves further investigation. In This study, a novel technology which combines Fenton reaction with fluidized bed reactor was developed. It not only desolves the seperation and disposal problem of traditional Fenton’s method but is highly efficient in mass transfer and degrading organic compounds. The preparation of GAC-supported FeOOH, batch adsorption and oxidation using FeOOH-GAC and GAC, GAC as supporter in Fenton-fluidiaed-bed reactor：adsorption, catalysis and chemical oxidation regeneration was investigated. In the part of operating condition of fluidized bed, the influence of different catalyst vloume and hydrous reaction time to COD and total Fe removal was investigated. The result indicated that the more the FeOOH-GAC was filled, the higher the Fe removal, meaning the more crystal on the GAC surface；besides, the longer is the HRT, the higher is the COD and total Fe removal. In the part of study of batch adsorption and oxidation, the 24 hours isothermal adsorption experiment of GAC and the two FeOOH-GAC were performed first, the result indicated that their adsorption efficiency was better at low pH than at high pH, and that the adsorption efficiency of GAC was higher than that of the two FeOOH-GAC；the adsorption efficiency of FeOOH-GAC(B) is higher than that of FeOOH-GAC(A).Subsequently the batch oxidation experiment was performed to investigate the feasibility of the catalysis oxidation of BA of the two catalyst, the addition of Fe2+ was found able to increase the catalysis oxidation. Besides, the existance of H2O2 was proved to increasingly oxidate GAC, and increased the TOC concentration of solution. Eventually an experiment for six weeks was performd to investigate the adsorption/catalysis/chemical oxidation regeneration process of the Fenton fluidized bed using GAC as supporter, which was crystallized for 2 weeks（inflowed organic compounds, NaHCO3 and Fenton reagent）→normally performed for 1 week→2~3 times the inflow organic compounds for 1 week→10 times the inflow organic compounds for 1 week→stopped the organic compounds inflow but continued the Fenton reagent inflow for 1 week→normal inflow, the change of the COD removal was observed during the process, then select and take out catalyst at typical time point to measure the quantity of BA adsorbed, from the change of COD removal and BA adsorption capacity, GAC was regenerated during the process.
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