以微波水熱法合成光觸媒硫化鎘結合氧化鈦奈米管去除水中氨氮之研究

Photocatalytic oxidation of ammonia over cadmium sulfide / titanate nanotube synthesized via microwave irradiation

陳志豪(Chih-Hao Chen)

指導教授 ： 駱尚廉

國立臺灣大學/工學院/環境工程學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.00867

摘要

摘要
氨氮(NH3/NH4+)是水中主要常見的含氮污染物之一，其存在不僅會對水中的生物造成影響，當水體存在過量氨氮時，還會造成魚類的死亡，同時也會降低對自來水的加氯消毒效果。現行氮氨處理技術包括有生物脫硝、氣提、折點加氯、離子交換等。光催化反應已被證實是一有效且具可行性之氧化方式，乃利用光觸媒受激發之電子進行一連串之化學反應所生成之氫氧自由基(OH∙)，再利用氫氧自由基具極強氧化能力之特性將氨氮予以氧化去除。
本研究利用微波水熱法製備硫化鎘(CdS)奈米粒子及氧化鈦奈米管(TNTs)，探討在不同條件下所合成之CdS、TNTs、CdS/TNTs對氨氮去除效果之影響。控制因子包括有溫度、功率、Cd/S比例，除了探討上述因子對光催化NH3造成之影響外，同時也配合一些物性分析如粒徑、孔隙、比表面積、SEM/EDX、XRD等對微波所合成之光觸媒做一輔助說明。另外本研究也將針對TNTs之離子交換能力做進一步之探討。
研究結果顯示當反應系統中存在CdS/TNTs時，由於光電子間傳遞效應之影響(Interparticle electron transfer, IPET)，其光催化去除NH3之效果比單純只使用CdS、TNTs之效果來得更好。TNTs之離子交換能力則有隨著微波功率增而有下降的趨勢。

關鍵字

光催化 ； 氨氮 ； 硫化鎘 ； 氧化鈦奈米管 ； 微波

並列摘要

Abstract
Aqueous ammonia (NH3/NH4+) is a major nitrogen-containing pollutants in wastewater. Its existence will be toxic to aquatic life and will cause fishes die. When there is high amount of ammonia in natural water, it will reduce the effect of disinfection in the treatments of tap water. Currently, there are some treatments for ammonia removal like biological nitrification, ammonia stripping, break-point chlorination and ion exchange. The photocatalytic reaction has been proved that it is an effective and a feasible method for ammonia removal . When photocatalysts are under UV illumination, the excited electron will follow a series of reaction and will produce the hydroxyl radicals (OH∙) which possess high ability of oxidation and then the ammonia will be oxidized.
The cadmium sulfide and titanate nanotubes (TNTs) were prepared by microwave hydrothermal method in this research, the efficiency of ammonia removal by using photocatalysts under different microwave conditions were also investigated. The control factors include temperature, irradiation power and Cd/S ratio. In addition to examining the effects of ammonia by the above factors, we also cooperate with the physical analysis like particle size analysis, pore volume analysis, specific surface area, SEM/EDX, XRD to make some assistant descriptions. However, the ion exchange ability of TNTs were also determined.
When there are CdS/TNTs in our photocatalytic system, the efficiency of ammonia removal was better than either only CdS or TNTs in the photocatalytic system. The result can be due to the interparticle electron transfer (IPET). Moreover, the ion exchange ability of TNTs decreased with the irradiation power increased.

並列關鍵字

Photocatalytic ； Ammonia ； CdS ； TNTs ； Microwave

參考文獻

中華民國環境工程學會編印，環境微生物，文太印刷，台北，1999

勞工安全衛生研究所，http://www.iosh.gov.tw

Chien, S. H., Liou, Y. C., Kuo, M. C., (2005) Preparation and characterization of nanosized Pt/Au particles on TiO2 nanotubes, Synth. Met. 152, 333-336.

Du, G. H., Chen, Q., Che, R. C., Yuan, Z. Y., Peng, L. M., (2001) Preparation and structure analysis of titanium oxide nanotubes, Appl. Phys. Lett. 79, 3702-3704.

Gacoin, T., Lahlil, K., Larregaray, P., (2001) Formation of CdS Colloids: Sols, Gels, and Precipitates. J. Phys. Chem. B, 105, 10228-10235.