釩結合二氧化鈦光觸媒提高可見光效率之研究

Enhancing visible light efficiency using vanadium and titanium dioxide photocatalysts

蕭雨柔(Yu-Jou Hsiao)

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(2013年)

https://doi.org/10.6346/NPUST.2013.00129

摘要

多氯聯苯(PCBs)因具穩定性高之特性，不易被生物分解，釋放至環境中經由空氣、水體、動植物以及土壤等介質之傳輸，累積於生物體中，而對人體及自然生態造成危害。多數光觸媒中以二氧化鈦(TiO2)最為廣泛使用，但需紫外光照射光觸媒才能產生效益，且電子電洞再結合亦是問題之一。本研究將以溶膠-凝膠法製備二氧化鈦結合釩(Vanadium)，並且比較純TiO2、0.3 wt%-V/TiO2、0.5 wt%-V/TiO2、0.7 wt%-V/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V/TiO2能加速日光下降解速率，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)之結果指出，添加釩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，在自然日光下經6小時後，純二氧化鈦、0.5 wt%-V/TiO2及0.7 wt%-V/TiO2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小時之自然日光降解，去除率可達43.84 %、礦化率為 15.35 %，再以離子層析儀(IC)分析生成Cl-之含量發現，隨著光照時間增加而提升；而PCBs的濃度則隨光照時間的增加而降低。經過五天的持久性試驗，溶膠凝膠法製備之二氧化鈦經600 ℃鍛燒是可重複利用的且符合目前環境保護之經濟效益的觸媒。

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

Polychlorinated biphenyls (PCBs) have been widely used in industries. PCBs 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. Titanium dioxide (TiO2) is one of the most widely used catalysts. However, it requires ultraviolet light to enhance its efficiency. The recombination of electron and hole is one of the problems. The sol-gel preparation of TiO2 composed with defferent amounts of Vanadium (V) are used to form pure TiO2, 0.3 wt%-V/TiO2, 0.5 wt%-V/TiO2, and 0.7 wt%-V/TiO2. Vanadium 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 V/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 Vanadium is capable of increasing the light absorption of TiO2. Degradation percentages for Pure TiO2, 0.5 wt%-V/TiO2 and 0.7 wt%-V/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 43.84 %, and 15.35 % of mineralization. The IC analysis found that with increasing illumination time, the yield of Cl- was increased. PCBs concentration decreased with increasing illumination times. 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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