- 期刊
銀／氧化鈦複合奈米纖維與甲基橙光降解特性
Photodegradation of methyl-orange by Ag/TiO_2 composited nanofibers under UV and visible irradiation
摘要
本研究藉由靜電紡絲技術製備具二氧化鈦／聚乙烯吡咯烷酮（TiO_2/PVP）。靜電紡絲是一種利用高分子溶液在高電場作用下由注射器噴出進行紡絲的過程。研究者利用改變高分子濃度、紡絲距離、注藥速率及電壓等參數製做成田口式直交表求得纖維直徑小與尺寸大小最緊密分布。以此條件完成的奈米纖維並使用高溫爐進行煅燒去除高分子及殘留溶劑，並使氫氧化鈦轉變為多晶銳鈦礦晶形，並使用掃描式電子顯微鏡觀測表面形貌來找到線徑均一且纖維成形良好的纖維參數。TiO_2為良好的光觸媒材料。將TiO_2/PVP浸泡甲基橙並照射紫外光以及泛波長光源以測定其光降解能力。其甲基橙溶液使用紫外光／可見光光譜儀量測其吸收度。在紫外光的照射下，TiO_2對甲基橙並無明顯降解效果，吸收度在溶液照射紫外光2小時在有機物吸收特徵峰接近0.8的位置，此歸因於TiO_2的能隙特性，在泛波長下對有機溶液的降解效率有限，照射泛波長至2小時，吸收度亦幾乎維持不變。利用光還原法將硝酸銀還原至奈米纖維上，還原銀的纖維其光降解能力有明顯的提升，甲基橙有機溶液在照射紫外光2小時溶液的有機物吸收特徵強度接近零，銀／氧化鈦奈米纖維複合材料在泛波長光源下對有機物的降解效率也因此提升，透過銀調變TiO_2奈米纖維可以有效提升其在甲基橙有機溶液的紫外光與可見光光降解能力。
並列摘要
In this study, titanium dioxide/polyvinylpyrrolidone (TiO_2/PVP) materials were prepared by electrospinning. Electrospinning is a process in which a polymer solution is spun from a nozzle under a high electric field for shaping. In this research project, the parameters of polymer concentration, electrospinning distance, injection rate and voltage were used to adopt the Taguchi orthogonal table to obtain the most uniform fiber diameter and unintentional low defect. The optimized nanofibers under this condition were calcined in a high-temperature furnace to remove the polymer and the residual solvent, and the material is converted into polycrystalline, and then the surface morphology is observed by a scanning electron microscope to obtain a fiber parameter having uniform size in diameter and good formation in morphology. In the literature, TiO_2 is a good photo-catalyst material. The TiO_2 after calcined treatment is immersed in methylene blue and methyl orange and irradiated with ultraviolet light and a broad wavelength source. The solution was measured for absorbance using an ultraviolet/visible spectrometer. Under ultraviolet light, TiO_2 has obvious degradation effects on methyl orange. The absorbance is close to zero at the absorption peak of organic matter when the solution is irradiated with ultraviolet light for 2 hours, but because of the characteristics of TiO_2 with bandgap of 3.2 eV, the degradation efficiency of the organic solution under solar simulator was limited, and the absorption wavelength remains almost unchanged after the irradiation of the broad wavelength to 2 hours. The photoreduction method was used to reduce the silver from silver nitrate to deposit on the surface of the nanofibers. The photo-degradation ability of the silver-anchored nanofibers was obviously improved. The absorption intensity of the organic matter in the solution of the organic solution after irradiating the ultraviolet light for 1 hour was close to zero. The degradation efficiency of the composite material consisted of Ag anchored TiO_2 NFs under the broad-wavelength light source is also improved.