Fe_3O_4硅烷化改性聚合物的制备及可见光光催化性能研究

Degradation of toxic organic pollutants by modified Fe_3O_4 under visible light irradiation

利用水热法制备了Fe3O4纳米粒子(Fe3O4NPs),并对其进行改性制备了改性聚合物Fe3O4MMPs.同时,利用X射线衍射(XRD)、扫描电镜(SEM)和紫外可见漫反射(DRS)等手段对所制备的材料进行表征.通过比表面积(BET)测定发现,Fe3O4MMPs的比表面积较Fe3O4NPs增大约9倍.在可见光照射下(λ>420 nm),以H2O2为氧化剂,比较研究了以Fe3O4NPs和Fe3O4MMPs为光催化剂降解罗丹明B(Rhodamine,RhB)的催化特性,并探讨了Fe3O4改性对催化活性的影响.结果表明,改性聚合物Fe3O4MMPs的稳定性增加,对底物RhB的降解活性提高,120 min时对RhB的脱色率在98%以上;此外,Fe3O4MMPs对水杨酸(Salicylic Acid,SA)也具有很好的降解效果.利用电子自旋共振技术(ESR)测定氧化物种的结果表明,降解过程涉及羟基自由基(·OH)和超氧自由基(·O-2)氧化机理.

Fe3O4nanoparticles(Fe3O4NPs) were synthesized by hydrothermal method and modified to prepare polymer Fe3O4 MMPs.The polymers were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and ultraviolet-visible diffuse reflectance spectroscopy(DRS).According to Brunauer-Emmett-Teller(BET) results,the specific surface area of Fe3O4 MMPs was 9 times larger than that of Fe3O4 NPs.The effect of modification on the photocatalytic activity of Fe3O4 MMPs was explored by comparing the removal efficiency of rhodamine B(RhB) by Fe3O4 NPs and Fe3O4 MMPs,respectively,using H2O2 as the oxidant and under visible light irradiation(λ > 420 nm).The results showed that the stability and photocatalytic activity of Fe3O4 MMPs were superior to those of Fe3O4 NPs.The decolorization rate of RhB reached 98% within 120 min.Moreover,salicylic acid(SA) could also be effectively removed by Fe3O4 MMPs.Electron spin resonance(ESR) technology was employed to detect oxygen species and the results implied that hydroxyl radical(·OH) and superoxide radical(·O-2) were predominate during the removal process.