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  本文選題：光催化氧化　切入點(diǎn)：草酸　出處：《哈爾濱工業(yè)大學(xué)》2015年碩士論文

【摘要】：煉化廢水產(chǎn)量大,污染成分復(fù)雜,采用傳統(tǒng)的“老三套”處理工藝,出水仍無法達(dá)到國家排放新標(biāo)準(zhǔn),因此有必要對煉化廢水進(jìn)行深度處理。由于二級處理后的煉化廢水可生化性較差,本文利用光催化氧化法進(jìn)行處理,并針對普通光-Fenton法產(chǎn)生鐵泥量大以及適用p H范圍有限的特點(diǎn),引入草酸提高了對煉化廢水的處理能力,并探討了反應(yīng)機(jī)制。本文采用沉淀法制備的針鐵礦為光催化劑,考察了Fe3+來源、反應(yīng)方式、陳化溫度及陳化時間等因素對合成針鐵礦的影響,并利用X射線衍射儀(XRD)、掃描電子顯微鏡(SEM)對不同因素制備的針鐵礦礦相及微觀形貌進(jìn)行表征,確定了適宜的催化劑制備條件。選用雙酚A(BPA)為目標(biāo)污染物,研究了針鐵礦的光催化性能。結(jié)果表明,采用將Na OH溶液逐滴滴加至Fe(NO3)3溶液中,在60 o C條件下陳化12 h以上可以得到結(jié)晶度高、呈現(xiàn)均勻棒狀的針鐵礦,對BPA的去除率達(dá)90%以上。以BPA為目標(biāo)污染物,建立了草酸促進(jìn)光助Fenton催化氧化水處理工藝,考察了各種因素對去除BPA的影響,得到最佳工藝條件為:草酸濃度為0.33 mmol/L,針鐵礦投加量為0.7 g/L,過氧化氫濃度為5.5 mmol/L,無需調(diào)節(jié)p H(約為6),在100 W紫外燈下反應(yīng)120 min,BPA去除率可以達(dá)到96.4%�？疾炝舜呋瘎┑姆�(wěn)定性和重復(fù)使用性,使用五個周期,針鐵礦催化劑對BPA的去除率可以保持在90%以上。對實驗數(shù)據(jù)進(jìn)行動力學(xué)擬合,反應(yīng)符合準(zhǔn)二級動力學(xué)模型,在最優(yōu)工藝條件下,反應(yīng)動力學(xué)速率常數(shù)為0.0225 L/(mol·min),半衰期為4.44 min。比較了不同工藝條件下BPA去除率以及·OH生成量的不同,探討了草酸促進(jìn)針鐵礦光催化氧化反應(yīng)機(jī)理。認(rèn)為在紫外光作用下針鐵礦與H2O2之間產(chǎn)生協(xié)同作用,使BPA去除率顯著提高;草酸的加入可以促進(jìn)體系分解H2O2生成·OH,進(jìn)一步提高BPA的去除率。設(shè)計了草酸促進(jìn)光助Fenton催化氧化深度處理煉化廢水的兩段式動態(tài)工藝裝置,系統(tǒng)由預(yù)處理段和光化學(xué)反應(yīng)段組成�？疾炝瞬菟釢舛�、Fe2+濃度、H2O2濃度、p H及預(yù)處理時間等因素的影響,確定了最佳工藝條件:草酸濃度為0.11mmol/L,H2O2濃度為6.6 mmol/L,Fe2+濃度為0.11 mmol/L,p H為6時,預(yù)處理15 min后在100 W紫外燈下反應(yīng)5 min,體系TOC的去除率可以達(dá)到70%以上。增加預(yù)處理段可以提高TOC去除率,降低藥劑使用量。
[Abstract]:Because of the large output of refinery wastewater and complex pollution composition, the effluent can not reach the new national discharge standard by using the traditional "old three sets" treatment process, so it is necessary to carry out advanced treatment of refinery wastewater.Due to the poor biodegradability of the secondary treated refinery wastewater, the photocatalytic oxidation process is used to treat the wastewater. The characteristics of the ordinary photo-Fenton process are the large amount of iron sludge produced and the limited application range of pH.Oxalic acid was introduced to improve the treatment capacity of refinery wastewater and the reaction mechanism was discussed.In this paper, the influence of Fe3 source, reaction mode, aging temperature and aging time on the synthesis of goethite was investigated by using goethite prepared by precipitation method as photocatalyst.X-ray diffractometer and scanning electron microscope (SEM) were used to characterize the phase and micromorphology of goethite prepared by different factors. The suitable preparation conditions of the catalyst were determined.The photocatalytic activity of goethite was studied with bisphenol A (BPA) as the target pollutant.The results show that the goethite with high crystallinity and uniform rod shape can be obtained by adding NaOH solution to Fe(NO3)3 solution one by one at 60 o C for more than 12 h, and the removal rate of BPA is more than 90%.With BPA as the target pollutant, the process of oxalic acid promoting photocatalytic oxidation of Fenton was established. The effects of various factors on the removal of BPA were investigated.The optimum technological conditions are as follows: oxalic acid concentration is 0.33 mmol / L, goethite dosage is 0.7 g / L, hydrogen peroxide concentration is 5.5 mmol / L, and the removal rate of BPA can reach 96.4g / L at 120 mins under 100W UV lamp without adjusting pH (about 6g 路L ~ (-1)).The stability and reusability of the catalyst were investigated. The removal rate of BPA of goethite catalyst was over 90% when used for five periods.The experimental data were fitted to the quasi-second-order kinetic model. Under the optimum conditions, the kinetic rate constant of the reaction was 0.0225 L/(mol / min and the half-life was 4.44 min.The mechanism of oxalic acid promoting photocatalytic oxidation of goethite was discussed by comparing the removal rate of BPA and the yield of OH under different conditions.It is concluded that the synergistic effect between goethite and H2O2 under ultraviolet light can increase the removal rate of BPA, and the addition of oxalic acid can promote the decomposition of H2O2 and further increase the removal rate of BPA.A two-stage dynamic process for advanced treatment of refinery wastewater using oxalic acid to promote photocatalytic oxidation of Fenton was designed. The system consists of pretreatment stage and photochemical reaction stage.The effects of oxalic acid concentration, Fe _ 2 concentration, H _ 2O _ 2 concentration and pretreatment time on H _ 2O _ 2 concentration and pretreatment time were investigated. The optimum conditions were determined as follows: oxalic acid concentration was 0.11 mmol / L ~ (-1) H _ (2) H _ 2O _ 2 was 6.6 mmol / L ~ (-1) Fe _ (2) concentration was 0.11 mmol / L ~ (-1) H _ (6),After pretreatment for 15 min, the removal rate of TOC was over 70% under 100W UV lamp for 5 mins.Increasing the pretreatment stage can increase the removal rate of TOC and reduce the dosage of medicament.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X742

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 陳琳,雷樂成,杜瑛s，

本文編號：1704057