Factors influencing the preparation of supported iron oxide in fluidized-bed crystallization.
Our previous work applied a novel supported iron oxyhydroxide (FeOOH) catalyst to effectively treat benzoic acid by hydrogen peroxide. The FeOOH catalyst was prepared via the oxidation of Fe2+ by H2O2 in the acidic condition using a fluidized-bed crystallization reactor. The major components coated on the surface were identified as amorphous FeOOH and gamma-FeOOH. In terms of the crystallization conditions of FeOOH, some parameters including the operational pH, superficial velocity, specific iron loading, and influent H2O2 concentration were investigated to quantify their effects on the crystallization efficiency. All these parameters were found to significantly influence the crystallization efficiency. Two types of FeOOH catalysts were synthesized: FeOOH I was prepared at pH 3.5, and FeOOH II was formed by aging FeOOH I at pH 13. The percentages of surface amorphous FeOOH reduced from 70% to 30% after aging. The FeOOH II catalyst presented a higher reactivity toward H2O2 but lower stoichiometric efficiency in oxidizing benzoic acid than FeOOH I, similar to the result of the commercial goethite. Therefore, it is concluded that the crystalline property significantly affects the performance of catalytic oxidation.
Chou
Shanshan
S
Environmental Technology Division, Center for Environmental, Safety & Health Technology Development, Industrial Technology Research Institute, 321 Kuang Fu Road, S-2, Hsinchu 300, Taiwan, ROC. shanshan_chou@itri.org.tw
Liao
Chi-Chung
CC
Perng
Shwu-Huey
SH
Chang
Sheng-Hsin
SH
D002384:Catalysis; D003460:Crystallization; D005290:Ferric Compounds / Q000737:chemistry*; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D018508:Water Purification / Q000379:methods*
D005290:Ferric Compounds; C000499:ferric oxide; D006861:Hydrogen Peroxide