鉻結合二氧化鈦光觸媒提升可見光利用之研究

Enhancing visible light efficiency using chromium and titanium dioxide photocatalysts

徐又中(Yu-Chung Hsu)

指導教授 ： 林耀堅

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2014年)

https://doi.org/10.6346/NPUST.2014.00130

摘要

亞甲基藍(Methylene Blue)為一種普遍的染料，能在很多物質表面產生吸附作用，常被使用於光觸媒分解實驗中，為研究調查之對象。多氯聯苯(PCBs)具高度穩定性、不易被生物分解且易累積於脂肪中之特性，排放至環境後將危害生物體及人體的健康。本研究以溶膠-凝膠法製備二氧化鈦結合鉻(Chromium)，並且比較純TiO2、0.3 wt% Cr-TiO2、0.5 wt% Cr-TiO2、0.7 wt% Cr-TiO2改質光觸媒之光催化能力，使其提高可見光吸收之區域，並進一步探討處理亞甲基藍與PCBs水溶液光解效能之研究。

研究結果顯示添加Cr確實能提升光觸媒可見光吸收範圍，於X-ray繞射分析儀(XRD)分析結果經資料庫(JCPDS)驗證，本研究所使用之觸媒為銳鈦礦(anatase)型TiO2。經掃描式電子顯微鏡(SEM)掃描結果顯示，添加鉻會使得觸媒顆粒表面孔隙增加，使其受光面積增加。從光降解試驗可知，在經過6小時自然光照下，純二氧化鈦、0.3 wt% Cr-TiO2及0.5 wt% Cr-TiO2對亞甲基藍降解率皆達99 %以上。以溶膠凝膠法所製備之二氧化鈦經600 ℃鍛燒下，對絕緣油之多氯聯苯進行降解6小時，其中以自然日光降解去除率可達57.05 %、礦化率為14.36 %。經過五天的持久性試驗，溶膠凝膠法製備之二氧化鈦，經600 ℃鍛燒，其可重複利用性較符合目前環境保護之經濟效益的。

關鍵字

二氧化鈦 ； 光觸媒 ； 可見光 ； 亞甲基藍 ； 多氯聯苯

並列摘要

Methylene blue is a common dye, and its high adsorption ability take place with the large surface of lots of materials. It is commonly used for photocatalytic decomposition experiments due to decolorization. Polychlorinated biphenyls (PCBs) have been widely used in industries that are highly stable man-made organic matters. However, PCBs are not easily biodegradable, a group of persistent organic pollutants. When PCBs released to the environment through the transportation of atmosphere, water, organisms and soil in the various environmental media, they can be accumulated in organisms because of the contamination in the environment. In this study, the sol-gel preparation of TiO2 composed with defferent amounts of Chromium (Cr) are used to form pure TiO2, 0.3 wt% Cr-TiO2, 0.5 wt% Cr-TiO2, and 0.7 wt% Cr-TiO2. Chromium was applied to enhance the photocatalytic capacity to improve the visible light absorption, and to further explore the treatment of methylene blue and PCBs aqueous solution.

The results of Cr-TiO2 investigation can accelerate degradation efficiency under natural sunlight. The XRD analytical results were used to compare the JCPDS authentication database used in this study to comfirm the crystal types of TiO2. The findings of SEM tests showed that the addition of chromium is capable of increasing the light absorption of TiO2. Degradation percentages for pure TiO2, 0.3 wt% Cr-TiO2 and 0.5 wt% Cr-TiO2 of methylene blue were more than 99 % under natural sunlight after 6 hours. The optimum operating conditions of photodegradation test results was using pure TiO2 at 600 ℃ under natural sunlight. The degradation percentages of PCBs were up to 57.05 %, and 14.36 % of mineralization. Titanium dioxide calcined at 600 ℃ by sol-gel method can be reused, and it conformed to the economical benefit of environmental protection issue.

並列關鍵字

titanium dioxide ； visble light ； methylene blue ； polychlorinated biphenyls ； photocatalyst

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