本文選題：BiOBr + 光催化��； 參考：《山東大學(xué)》2017年碩士論文

【摘要】：近幾年,隨著中國經(jīng)濟(jì)和工業(yè)的高速發(fā)展,環(huán)境污染越來越嚴(yán)重,大氣污染問題逐漸獲得重視,其中,揮發(fā)性有機(jī)物(VOCs)更是受到了廣大學(xué)者的關(guān)注。苯系物是VOCs的重要組成成分,其非常難降解、在環(huán)境空氣中濃度較高且對(duì)環(huán)境和人體的危害較大。在苯系物的眾多治理技術(shù)中,光催化氧化法具有操作過程簡單、污染物去除效率高、運(yùn)行能耗低、經(jīng)濟(jì)可行且無二次污染等優(yōu)點(diǎn),成為治理VOCs的新趨勢。BiOBr是一種新型的光催化材料,由于其具有獨(dú)特的層狀結(jié)構(gòu)和優(yōu)良的光催化性能,得到了廣大研究者的關(guān)注,BiOBr通過不同的方法制備,會(huì)得到不同的結(jié)構(gòu)及性質(zhì)。因此,此次研究的目的是尋找一種簡單有效的方法制備出具有高的光催化性能的BiOBr催化劑,用制備出的BiOBr作為催化劑,在紫外光下催化降解氣相苯系物并探討降解過程中的影響因素及光催化降解動(dòng)力學(xué)規(guī)律。本實(shí)驗(yàn)以Bi(N03)3·5H20為鉍源,KBr為溴源,乙二醇為溶劑,利用溶劑熱法來制備所需的BiOBr催化劑,實(shí)驗(yàn)發(fā)現(xiàn):制備的BiOBr的催化活性受制備過程中的溶劑熱溫度和初始反應(yīng)物中Bi與Br的摩爾比的影響。通過XRD、SEM和BET對(duì)制備的BiOBr催化劑進(jìn)行了表征,發(fā)現(xiàn)Bi與Br的摩爾比為1:1時(shí)制備的BiOBr催化劑的結(jié)晶性最好;120℃溶劑熱溫度時(shí)制備的BiOBr催化劑微球具有結(jié)晶性好、尺寸均勻、分散良好、微球由較多的單片狀催化劑構(gòu)成、催化劑山中孔和微孔結(jié)構(gòu)構(gòu)成、比表面積大等優(yōu)點(diǎn)。在光催化反應(yīng)中,采用Bi與Br的摩爾比為1:1且120℃時(shí)制備的BiOBr作為催化劑,紫外光照射90min后,苯的降解率為82.86%,鄰二甲苯的降解率為98.30%,結(jié)果表明,在紫外光下,苯系物的降解效果由大到小依次為二甲苯,甲苯和苯,而二甲苯的三種異構(gòu)體的的降解效果山大到小為鄰二甲苯,間二甲苯和對(duì)二甲苯。此次實(shí)驗(yàn)探討了光催化過程中苯系物初始反應(yīng)濃度和BiOBr投加量對(duì)催化反應(yīng)的影響。結(jié)果表明,當(dāng)BiOBr投加量一定時(shí),隨著苯系物初始反應(yīng)濃度的增加,苯系物的降解率反而下降;BiOBr在低投加量下,隨著BiOBr投加量的增加,苯系物的降解效率增大,當(dāng)BiOBr的投加量達(dá)到一定量后,隨著BiOBr投加量的增加,苯系物的降解效率變化不明顯。本實(shí)驗(yàn)對(duì)苯系物光催化降解動(dòng)力學(xué)規(guī)律進(jìn)行研究,發(fā)現(xiàn)苯系物光催化降解過程符合一級(jí)反應(yīng)動(dòng)力學(xué)規(guī)律。對(duì)于催化反應(yīng)來說,催化劑的使用壽命是衡量催化劑使用效果的一個(gè)重要指標(biāo)。為了考察實(shí)驗(yàn)中制備的BiOBr的穩(wěn)定性,確定其使用壽命,本實(shí)驗(yàn)以苯作為苯系物的代表物來考察BiOBr催化劑的穩(wěn)定性,重復(fù)四次實(shí)驗(yàn)后,發(fā)現(xiàn)苯的降解率由82.86%下降至77.95%,降解率沒有明顯降低,結(jié)果表明:制備的BiOBr催化劑性質(zhì)穩(wěn)定,可以重復(fù)利用。
[Abstract]:In recent years, with the rapid development of economy and industry in China, environmental pollution is becoming more and more serious, and the problem of air pollution has been paid more and more attention. Benzene series is an important component of VOCs, which is very difficult to degrade, and has a high concentration in the ambient air and great harm to the environment and human body. Among the many treatment technologies of benzene series, photocatalytic oxidation has the advantages of simple operation, high pollutant removal efficiency, low energy consumption, economic feasibility and no secondary pollution. BiOBr is a new kind of photocatalytic material. Because of its unique layered structure and excellent photocatalytic performance, BiOBr has attracted the attention of many researchers in the preparation of BiOBr by different methods. Different structures and properties will be obtained. Therefore, the purpose of this study is to find a simple and effective method to prepare BiOBr catalyst with high photocatalytic performance, using the prepared BiOBr as catalyst. The catalytic degradation of gaseous benzenes under ultraviolet light was carried out and the influencing factors and kinetics of photocatalytic degradation were discussed. In this experiment, Bi(N03)3 5H20 was used as bismuth source and KBR as bromine source and ethylene glycol as solvent to prepare BiOBr catalyst by solvothermal method. It is found that the catalytic activity of the prepared BiOBr is affected by the solvothermal temperature and the molar ratio of Bi to Br in the initial reactants. The prepared BiOBr catalyst was characterized by XRDA SEM and BET. It was found that the crystallinity of the BiOBr catalyst prepared at 1:1 was the best when the molar ratio of Bi to Br was 1:1. The BiOBr catalyst microspheres prepared at 120 鈩，

本文編號(hào)：1844971