中文摘要：

自然界广泛存在羟基氧化铁，研究其在地质中的光催化作用对环境的污染防治有着重要意义。在自然光照下。用针铁矿和四方纤铁矿处理甲基橙溶液，不同反应时间取样经高速离心后，用紫外／可见分光光度计和傅立叶变换显微红外光谱仪（FTIR）进行分析。结果表明，FeOOH／Visible light体系能使甲基橙溶液脱色率达83％，四方纤铁矿比针铁矿有更好的光催化降解效果；FeOOH／Vismle light体系能将甲基橙分子中的偶氮键打开，从而使溶液脱色，FeOOH／VisIhle lihgt／H2O2则能进一步降解甲基橙，使其分子中的苯环部分打开。

英文摘要：

Iron oxyhydroxides are widely existed in natural environment. To study their photocatalysis in geological environment is important for preventing environmental pollution. Two nanometer sized oxyhydroxides of α-FeOOH and β-FeOOH are selected to degrade methyl orange in water system under visible light in this study. Samples, collected from the solution at different reaction times, were centrifugalized first and then analyzed by UV-vis spectrometry and FTIR spectrometry respectively. The results show that decoloration rate of methyl orange in solution can be up to 83 % in FeOOH/Visible light system, the photocatalysis of β-FeOOH on methyl orange is more effective than that of α-FeOOH. The FeOOH/Visible light system can break the azo bond and decolor the methyl orange in solution. The phenyl in methyl orange molecule can be partially degraded in the FeOOH/Visible light/H2O2 system.