Mixed iron oxides as Fenton catalysts for gallic acid removal from aqueous solutions
Mixed iron oxides as Fenton catalysts for gallic acid removal from aqueous solutions
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DOI：
10.1016/j.apcatb.2016.05.032
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发表时间：
2016-11-05
影响因子：
22.1
通讯作者：
Alvarez, Miguel A.
中科院分区：
文献类型：
--
作者：
Fontecha-Camara, Maria A.;Moreno-Castilla, Carlos;Alvarez, Miguel A.
研究了三种商业混合铁氧化物（铁酸铜、磁铁矿和钛铁矿）作为芬顿催化剂的行为，使用H2O2在15至35 ℃之间的温度和pH 4.3下降解和矿化没食子酸（GA）。催化剂的活性的调查补充了在反应条件下的金属离子浸出的研究。3种铁氧化物对GA的催化活性顺序为CuFe_2O_4> Fe_3O_4> FeTiO_3，且在磁场作用下，铁氧化物能迅速完全分离。这些结果表明，Cu和Fe离子在八面体中存在协同效应，Cu离子可能是HO中心点自由基生成的主要活性位。H2O2的利用效率遵循混合铁氧化物的催化活性的逆序，这可能是因为在反应过程中产生的过量羟基自由基被过氧化氢淬灭，产生反应性较低的氢过氧化物自由基。在较高的反应温度下，大量的Cu和Fe离子从铁酸铜中浸出并减少。这些浸出的离子也作为均匀的芬顿催化剂在GA的降解和矿化。与铁酸铜相比，从磁铁矿和钛铁矿中浸出的铁离子量低得多。从长期应用的角度来看，具有中等催化活性但与铁酸铜相比具有更高效率和更低的Fe离子浸出的磁铁矿可能更适合于GA去除。(C)2016爱思唯尔B.V.保留所有权利。
A study was conducted on the behavior as Fenton catalysts of three commercial mixed iron oxides: copper ferrite, magnetite, and ilmenite, using H2O2 for the degradation and mineralization of gallic acid (GA) at temperatures between 15 and 35 degrees C and pH of 4.3. Investigation of the activity of the catalysts was complemented by study of the metal ion leaching under reaction conditions. GA was completely mineralized with the three mixed iron oxides in the following order of catalytic activity: CuFe2O4 > Fe3O4 > FeTiO3, and the ferrites could be quickly and completely separated after the reaction by a magnetic field. According to these results, there appears to be a synergic effect between Cu and Fe ions placed in octahedral sites, and Cu ions may be the main active sites for HO center dot radical generation. The efficiency of H2O2 utilization followed the inverse order of the catalytic activity of the mixed iron oxides, likely because the excess hydroxyl radicals generated during the reaction were quenched by hydrogen peroxide, yielding the less reactive hydroperoxide radicals. A very large amount of Cu and Fe ions leached from copper ferrite and decreased at higher reaction temperatures. These leached ions also acted as homogeneous Fenton catalysts in GA degradation and mineralization. A much lower amount of Fe ions was leached from magnetite and ilmenite in comparison to copper ferrite. From the perspective of long-term applications, magnetite with intermediate catalytic activity but with higher efficiency and much lower Fe ion leaching in comparison to copper ferrite may be more appropriate for GA removal. (C) 2016 Elsevier B.V. All rights reserved.