中文摘要：

选取了磁铁矿、赤铁矿和针铁矿3种不同晶型的铁氧化物,用XRD和BET进行了表征。将3种铁氧化物作为催化剂用于Fenton和UV-Fenton（254 nm UVC）降解偶氮染料橙II,测定了染料降解过程中溶液中铁离子浓度的变化规律,用于分析3种铁氧化物的催化过程。用单位比表面积反应速率常数（k/Ssur）评价了3种铁氧化物UV-Fenton催化降解橙Ⅱ的能力,以揭示UV-Fenton体系中铁氧化物晶型与催化性能的关系。结果表明,Fenton体系中,磁铁矿能通过表面固有的2价铁催化产生羟基自由基降解橙Ⅱ,其催化能力高于针铁矿和赤铁矿;UV-Fenton体系中,磁铁矿、赤铁矿和针铁矿催化降解橙Ⅱ的单位比表面积反应速率常数分别为0.048 8 g/（m2·min）、0.023 4 g/（m2·min）和0.001 0 g/（m2·min）,可见磁铁矿的催化能力明显高于针铁矿和赤铁矿;UV-Fenton体系中,磁铁矿以多相反应为主,针铁矿以均相反应为主,而赤铁矿则是两者共同作用。研究表明,磁铁矿是多相铁氧化物UV-Fenton催化剂的理想晶型,同时也是合成新型多相光助-芬顿催化剂理想的活性组分。

英文摘要：

The paper is intended to study the relation between the catalytic features of different crystal forms of iron oxides in Fenton and UV-Fenton systems. For this purpose,we have prepared three kinds of iron oxides with different crystal forms,including magnetite,hematite and goethite ones. In addition,we have also taken the said iron oxides as the catalysts for azo dye degradation of Orange II in the sewage so as to determine the total iron ion concentration as a function of time in Fenton and UV-Fenton systems. At the same time,we have also examined the catalytic process of the aforementioned catalysts by way of comparing the homogeneous UV-Fenton system with that of heterogeneous UVFenton. And,finally,we have worked out the catalysis capability of the three iron oxides in UV-Fenton system with the degradation rate constant per unit specific surface area（ k/Ssur）. The results of our experiments indicate that in Fenton system,the catalytic activity of the magnetite tends to be more intensive than that of hematite and goethite,for the hydroxyl radical can be generated directly by the catalyzed decomposition of H_2O_2 with the surface Fe~（2＋） of the magnetite. Specifically speaking,Orange Ⅱ degradation rate constants per unit specific surface area of magnetite,hematite and goethite in UV-Fenton system have been found equal to 0. 048 8 g/（ m~2·min）,0. 023 4 g/（ m~2·min） and 0. 001 0g/（ m2·min） respectively,which indicate that the catalytic activity of magnetite turns out to be more intensive than that of hematite and goethite. On the other hand,for UV-Fenton system,the catalytic reaction of magnetite should be mainly taken as a heterogeneous process,whereas that of goethite should be primarily taken as a homogeneous process,and the catalytic reaction of hematite can be said including homogeneous and heterogeneous ones. Thus,it can be concluded that magnetite can be regarded as an ideal crystalized form of the iron oxide for heterogeneous UV-Fenton system and an ideal active species for explor