活性炭镀TiO2薄膜光催化降解苯酚废水

本文研究用常压化学气相沉积法对活性炭镀TiO2薄膜催化剂的条件下．以紫外灯为光源,进行苯酚废液光催化降解。实验得出：(1)活性炭的量不同;(2)底物的种类不同;(3)分别用HCl、NaOH处理活性炭后再镀TiO2薄膜;(4)镀TiO2薄膜时水的温度不同;(5)在溶液中加入不同的物质(H2O2、CH2COCH3),均对苯酚废液的降解有影响,结果表明：镀膜底物为活性炭,水温度为30℃．溶液中加入H2O2时对苯酚废液的光催化效果最好。     

Performance of a photo‐impinging streams reactor for the phenol degradation process

BACKGROUND: Photocatalysis is one of the advanced oxidation processes that has gained in importance over recent years owing to its ability to decompose a wide range of organic and inorganic pollutants at ambient temperature and pressure. However, there are two essential issues regarding photocatalytic processes, i.e. limitations on photon transfer and on mass transfer. In the present study, a novel photo‐impinging streams reactor, which can minimize such limitations, has been utilized in the photocatalytic degradation of phenol. The design and operating parameters such as type of nozzle, flow rate, catalyst loading, pH, initial phenol concentration and light intensity were found to have the expected impact on the efficiency of the process. The effects of two different co‐oxidants, H₂O₂ and Na₂S₂O₈ on the photocatalysis were also examined. RESULTS: Results indicated that 100 mg L^?1 of phenol in a 750 cm³ solution was completely degraded within 2.5 h reaction time in the presence of TiO₂ without a co‐oxidant present; and within 1 h in the presence of a co‐oxidant. CONCLUSION: A comparison between the current data and those available in the literature revealed higher efficiency and increased performance of the present reactor relative to conventional apparatus. Copyright © 2010 Society of Chemical Industry     

Influence of operating parameters on photocatalytic degradation of phenol in UV/TiO2 process

The use of hydrogen peroxide (H₂O₂) for improved photocatalytic degradation of phenol in aqueous suspension of commercial TiO₂ powders (Degussa P-25) was investigated. Photodegradation was compared using direct photolysis (UV alone), H₂O₂/UV, TiO₂/UV, and H₂O₂/TiO₂/UV processes in a batch reactor with high-pressure mercury lamp irradiation. The effects of operating parameters such as catalyst dosage, light intensity, pH of the solution, the initial phenol, and H₂O₂ concentrations on photodegradation process were examined. It was shown that photodegradation using H₂O₂/TiO₂/UV process was much more effective than using either H₂O₂/UV or TiO₂/UV process. The effect of the initial phenol concentration on TOC removal was also studied, demonstrating that more than 8 h was required to completely mineralize phenol into water and carbon dioxide. For all the four oxidation processes studied, photodegradation followed the first-order kinetics. The apparent rate constants with 400-W UV ranged from 5.0 × 10⁻⁴ min⁻¹ by direct photolysis to 1.4 × 10⁻² min⁻¹ using H₂O₂/TiO₂/UV process. The role of H₂O₂ on such enhanced photodegradation of phenol in aqueous solution was finally discussed.     

TiO2改性竹炭的制备及光催化降解苯酚的研究

采用溶胶-凝胶法制备了TiO2/竹炭复合材料。利用XRD、SEM对该材料进行了表征。结果表明,TiO2/竹炭结构中TiO2以锐钛矿相存在,同时负载在竹炭表面后TiO2的粒径变小。以苯酚模拟废水的降解率考察TiO2/竹炭复合材料的光催化活性,结果表明,TiO2/竹炭复合材料具有较高的光催化活性,最佳条件下,TiO2/竹炭复合材料对苯酚的降解率为56.36%。     

氨基甲酸酯类化合物的二氧化钛光催化降解研究

本文研究了纳米二氧化钛光催化降解水中氨基甲酸酯类化合物,实验结果表明纳米二氧化钛能将其有效地降解成无毒的无机产物;同时监测了降解过程中的氮类无机产物的含量,发现氨基甲酸酯类化合物在光催化过程中先被氧化分解成NH4^＋再进一步被氧化成NO3^-。     

Solar‐assisted photochemical and photocatalytic degradation of phenol

Photocatalytic (TiO₂, air and solar radiation) and photochemical (H₂O₂ and solar radiation) mineralizations of phenol solutions (up to 500 mg dm^?3) in a batch reactor using concentric solar radiation were studied. A compound parabolic reflector as a concentrating reflector was used to obtain concentrated solar radiation in both cases. Considerable enhancement (Five‐fold) in the rate of degradation was obtained when concentrated solar radiation was used instead of plain solar radiation in photocatalytic degradation. The effect of initial phenol concentration, intensity and presence of anions has been studied in both the cases. Low concentrations of intermediates were observed, during the reaction, over the entire range of phenol concentrations studied in the case of photocatalytic degradation using Degussa‐P25 TiO₂ as photocatalyst and in the absence of anions; whereas significant quantities of intermediates were observed in the case of the photochemical degradation. The presence of anions generally had a detrimental effect on the mineralization process in both cases. Different anions showed different effects. Total organic carbon (TOC) variations with time were also studied. A rational explanation has been given for the decrease in the rate in the presence of anions. © 2001 Society of Chemical Industry     

TiO2／斜发沸石光催化降解罗丹明B的研究

制备了一系列TiO2／斜发沸石催化剂（不同焙烧温度、不同粒度和不同负载量），它们在紫外光照射下可降解有机染料罗丹明B（RhB）．发现焙烧温度为500℃、粒度为180—200目、TiO2实际质量分数为6．18％的催化剂样品活性较好．将其与P25对比，发现其降解速率虽低于P25（紫外光照84min，P25COD变化率为100％，而焙烧温度为500℃的TiO2／斜发沸石催化剂经紫外光照5．5h，COD变化率为71．8％），但是TiO2／沸石催化剂易于回收再利用，而纯P25因为颗粒细小，沉降速率慢，而不能快速分离．用XRD、TEM、BET、TG—DTA和紫外可见漫反射等方法表征了这些催化剂，结果表明催化剂比表面积增大有利于催化活性的提高．     

纳米TiO2/沸石复合材料光催化降解苯酚的性能

苯酚是一种较难处理的有毒有机污染物。本文以TiOSO₄为钛源,尿素为沉淀剂,沸石为载体,采用均匀沉淀法制备了纳米TiO₂/沸石复合材料,并以苯酚作为降解对象,研究了不同TiO₂负载量、煅烧温度以及重复使用对纳米TiO₂/沸石复合材料的光催化降解苯酚性能的影响。结果表明:TiO₂负载量为30%、煅烧晶化温度为650℃时,经300W高压汞灯照射3.5h,纳米TiO₂/沸石复合材料对20mg/L苯酚溶液的光催化降解率达到91.6%;重复使用5次仍对苯酚溶液具有85%的光催化降解率。     

TIO2-photocatalyzed degradation of phenol and ortho-substituted phenolic compounds

The photocatalytic degradation of phenol, guaiacol, 2-chlorophenol and catechol in aqueous suspensions of TiO₂ under different experimental conditions has been investigated. The photodegradation of the different organics follows a Langmuir–Hinshelwood kinetics, showing rate constants that decrease in the order: guaiacol>2-chlorophenolphenol>catechol. A similar trend is also observed, except for catechol, for the stability of the σ-complexes that may be formed between the aromatic ring and the OH√ radical. From different analytical techniques (HPLC, GC/MS and HPLC/MS), various hydroxylated intermediate compounds have been reported and different mechanisms of degradation of the starting compounds have been proposed. From experiments performed using aqueous solutions containing the four organics, it is observed that the competitive Langmuir–Hinshelwood kinetics for the degradation of each one of the phenolic compounds is obeyed.     

铈掺杂纳米二氧化钛可见光光催化降解苯酚性能

采用Ce（NO3）3掺杂改性后的纳米TiO2粉末作为光催化剂（Ce-TiO2）,研究了Ce-TiO2在可见光条件下光催化降解苯酚的过程,考察了Ce掺杂量、焙烧温度、焙烧时间、pH值以及催化剂用量等因素对苯酚溶液光催化降解过程的影响。结果表明：可见光照射下,当Ce掺杂量为1.00%、焙烧温度为700℃、焙烧时间为3 h、反应溶液pH值为5、催化剂投加量为1.0 g/L时,苯酚的去除率达到最佳,为35.8%。     

SnO2-Sb2O3-CeO2/Ti电催化电极制备及氧化苯酚研究

采用电沉积制备中间层,热分解制备表层的方法制备了钛基铈掺杂锡锑涂层电极,利用SEM、EMPA、动电位扫描,研究了电极涂层形貌、元素组成分布、选择催化性.结果表明:电极表面涂层颗粒分布均匀,电极涂层有较大的表面积,Sn、Sb、Ce 3种元素分布较均匀;电极有较高的析氧电位.苯酚降解试验表明:低浓度时苯酚和CODCr有较高...     

负载型TiO2/SiO2光催化降解苯酚的研究

以白炭黑为载体、聚乙烯醇 (PVA) 和 Ti(SO₄)₂ 为原料， 在分散剂存在下直接焙烧制备超细负载型 TiO₂/SiO₂ 光催化剂， 结果表明， 在450 ℃焙烧2 h所制 SO₄^2-/TiO₂-SiO₂（SO₄^2-质量分数3.4%，TiO₂∶SiO₂=1∶6，比表面积54 m²/g）具有最佳光催化效果。光催化苯酚结果显示,在紫外灯下光降解苯酚（＜100 mg/L）符合零级动力学方程，催化活性随pH值的增加而增加，pH=10时表观速率常数[WTBX]k[WTBZ]=0.33 mg/L·min，为苯酚废水处理提供了一条简便易行、成本低廉的方法。同时考察了光催化剂制备因素对催化剂活性的影响。     

Ti/IrO_2-RuO_2电极降解苯酚红废水

利用热分解法制备Ti/IrO_2-RuO_2电极,以该电极为阳极处理苯酚红(PR),并优化其最佳处理条件。结果表明:在电流密度为15 mA·cm-2、电解质Na2SO4浓度为6.0 g·L-1、废水溶液起始pH=7、反应温度为40℃时,处理120 min后PR废水的降解率为74.5%。     

模拟煤炭气化废水中苯酚的微生物降解

苯酚是煤炭气化废水中一种典型的有机污染物,其处理受到广泛关注和研究。本文采用连续驯化和平板划线法从焦化废水和气化废水中筛选出两种苯酚高效降解菌株,分别命名为JHFS-1和QHFS-1;通过苯酚溶液的微生物降解实验研究了温度、pH、摇床转速、细菌接种量、Cu²⁺和Mn²⁺等对苯酚降解效果的影响,还考察了模拟煤炭气化产生的煤气洗涤水的微生物净化修复效果。结果发现：经16S rDNA基因测序和微生物学鉴定,两种菌株均为醋酸钙不动杆菌(Acinetobacter calcoaceticus);30℃、pH=6.0、摇床转速120r/min、接种量13%是苯酚的最优降解条件,经24h处理,苯酚降解率可达94.31%;Cu²⁺对JHFS-1降解苯酚有一定的抑制作用,Mn²⁺一定程度上促进JHFS-1对苯酚的降解;微生物对苯酚的降解遵从羟基化途径和羧基化途径;JHFS-1菌可有效降解煤气洗涤水中的有机污染物,其总有机碳(TOC)降解率达58.43%。     

MCM负载型TiO2/Pd光催化剂的制备及其性能研究

研究了用分子筛MCM多孔材料作载体，制备了负载型MCM-TiO2和MCM-TiO2/Pd催化剂。在带CCD的T64000型色散光谱仪上得到了样品的拉曼光谱。比较了样品对对甲基苯酚的光催化降解性能，并探讨了不同温度焙烧样品对对甲苯酚光降解率的影响。     

微波/过氧化氢协同降解苯酚动力学

研究了微波/过氧化氢（MW/H₂O₂）系统催化氧化降解苯酚的动力学。结果表明,在单独的微波辐射（MW）或者过氧化氢（H₂O₂）氧化条件下苯酚去除率很小,而在MW/H₂O₂系统中有显著的提高,表明协同效应存在。另外,在三种工艺条件下苯酚的降解均符合表观一级动力学。在MW/H₂O₂系统中苯酚去除的速率常数增强因子可达到5.98,根据此系统中存在MW、H₂O₂和羟基自由基（·OH）三部分协同作用的降解机理,推导出了简化的苯酚降解动力学模型,较好的反应过氧化氢浓度过量条件下的苯酚降解。     

TiO2/浮石的制备及其光催化性能的研究

以浮石为载体,采用浸渍法制备负载型光催化剂TiO2/浮石,研究微波辅助光催化体系对以活性艳红X-3B的脱色反应,并与Al2O3、分子筛、玻璃细球为载体的光催化剂进行比较.结果显示,微波对TiO2/浮石光催化有辅助作用,TiO2/浮石的催化活性最好.进一步研究了pH、H2O2滴加量,催化剂寿命对TiO2/浮石反应体系的影响,实验证明,TiO2/浮石结构性能稳定,活性持久,适宜于工业应用.     

Kinetic study on the UV‐induced photopolymerization of epoxy acrylate/TiO2 nanocomposites by FTIR spectroscopy

The kinetics of the photopolymerization of epoxy acrylate/TiO₂ nanocomposites, with 2′2‐dimethoxy‐1,2‐diphenylethan‐1‐one (Irgacure 651) or benzophenone/N‐methyl diethanolamine as photoinitiators, were studied by FTIR spectroscopy. It was found that nanocomposites had a decreasing photopolymerization rates in comparison with pure epoxy acrylate. The photopolymerization rate of the nanocomposite could also be influenced by initiator types, oxygen, film thickness, irradiation intensity, dispersing media of TiO₂ slurry, and so forth. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3281–3287, 2006