TiO2/Ni-Cu-Zn鐵氧體磁性光觸媒的合成與特性分析

Synthesis and Characterization of TiO2/Ni-Cu-Zn Ferrite Powders for Magnetic Photocatalyst

傅彥培(Yen-Pei Fu) ； 王信超(Shin-Chau Wang)

《臺灣鑛業》 62卷4期 (2010/12) Pp. 39-48

https://doi.org/10.30014/TMI.201012.0005

摘要

本研究中我們成功地製備作為磁性光觸媒的TiO2／Ni-Cu-Zn鐵氧體核殼粉末。利用鋼鐵酸洗溶液和電鍍後的廢液當作起始材料，去合成Ni-Cu-Zn鐵氧體粉體核心，而TiO2奈米晶體殼層則是利用溶膠－凝膠法製備，使得Ni-Cu-Zn鐵氧體粉末表面覆蓋一層鈦酸四異丙酯（Ti(OC3H7)4）的水解沉澱物，最後去做熱處理。從穿透式電子顯微鏡影像，發現二氧化鈦外殼層厚度大約5 nm。Ni-Cu-Zn鐵氧內核的形狀有圓形和橢圓形，而且粉體大小範圍在70～110 nm。磁性Ni-Cu-Zn鐵氧體奈米粉體均勻的包覆二氧化鈦層，形成TiO2/Ni-Cu-Zn鐵氧體合成粉體的核－殼結構。隨著磁性光觸媒含量增加，對於亞甲基藍的降解效率也增加。當150 ml亞甲基藍裡含有0.4 g磁性光觸媒時，光觸媒活性達到最大值。若進一步增加磁性光觸媒含量，則降解效率些微降低。這是由於懸浮在亞甲基藍上的觸媒，遮蓋了UV光照射，而抑制了光觸媒的反應。在亞甲基藍濃度與照射之間的光觸媒的降解結果，呈現出速率決定步驟常數1.717 mg/L‧min和平衡吸收常數0.0627L/mg的近似一階動力模式。此外，Langmuir-Hinshewood模式可以用來說明此降解反應的速率決定步驟是由表面反應速率決定而不是吸附速率為之。

關鍵字

磁性光觸媒 ； 核殼結構 ； 光催化反應

並列摘要

In the current research, we successfully prepared TiO2/Ni-Cu-Zn ferrite composite powder for magnetic photocatalyst. The core Ni-Cu-Zn ferrite powder was synthesized by using the steel pickling liquor and the waste solution of electroplating as the starting materials. The shell TiO2 nanocrystal was prepared by sol-gel hydrolysis precipitation of titanium isopropoxide (Ti(OC3H7)4) on the Ni-Cu-Zn ferrite powder followed by heat treatment. From transmission electron microscopy (TEM) image, the thickness of the titania shell was found to be approximately 5 nm.The core of Ni-Cu-Zn ferrite is spherical or elliptical shape and the particle size of the core is in the range of 70~110nm. The magnetic Ni-Cu-Zn ferrite nanopowder is uniformly encapsulated in a titania layer forming core-shell structure of TiO2/Ni-Cu-Zn ferrite powder. The degradation efficiency for methylene blue (MB) increases with magnetic photocatalyst (TiO2/Ni-Cu-Zn ferrite powder) content. When the magnetic photocatalyst content is 0.40g in 150mL of MB, the photocatalytic activity reached the largest value. Further increasing the content of magnetic photocatalyst, the degradation efficiency slightly decreased. This is due to the fact that the UV illumination is covered by catalysts, which suspended in the methylene blue solution and resulting in the inhibition in the photocatlyic reaction. The photocatalytic degradation result for the relationship between MB concentration and illumination, it revealed a pseudo first-order kinetic model of the degradation with the limiting rate constant of 1.717mg/L‧min and equilibrium adsorption constant 0.0627L/mg. Furthermore, the Langmuir-Hinshewood model can be employed to describe the degradation reaction, which suggests that the rate-determining step is surface reaction rather than adsorption is in photocatalytic degradation.

並列關鍵字

Magnetic photocatalyst ； Core-shell structure ； Photocatlyic reaction