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1.
This work shows that aqueous solutions of clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid), the bioactive metabolite of various lipid-regulating drugs, up to saturation at pH 3.0 are efficiently and completely degraded by electrochemical advanced oxidation processes such as electro-Fenton and photoelectro-Fenton with Fe 2+ and UVA light as catalysts using an undivided electrolytic cell with a boron-doped diamond (BDD) anode and an O 2-diffusion cathode able to electrogenerate H 2O 2. This is feasible in these environmentally friendly methods by the production of oxidant hydroxyl radical at the BDD surface from water oxidation and in the medium from Fenton's reaction between Fe 2+ and electrogenerated H 2O 2. The degradation process is accelerated in photoelectro-Fenton by additional photolysis of Fe 3+ complexes under UVA irradiation. Comparative treatments by anodic oxidation with electrogenerated H 2O 2, but without Fe 2+, yield much slower decontamination. Chloride ion is released and totally oxidized to chlorine at the BDD surface in all treatments. The decay kinetics of clofibric acid always follows a pseudo-first-order reaction. 4-Chlorophenol, 4-chlorocatechol, hydroquinone, p-benzoquinone and 2-hydroxyisobutyric, tartronic, maleic, fumaric, formic and oxalic acids, are detected as intermediates. The ultimate product is oxalic acid, which is slowly but progressively oxidized on BDD in anodic oxidation. In electro-Fenton this acid forms Fe 3+–oxalato complexes that can also be totally destroyed at the BDD anode, whereas in photoelectro-Fenton the mineralization rate of these complexes is enhanced by its parallel photodecarboxylation with UVA light. 相似文献
2.
考察了MnO 2-FeS 2-H 2SO 4细菌浸出体系下,嗜酸氧化亚铁硫杆菌和Fe 3+单独或联合对MnO 2浸出Mn 2+的浸出速率影响,并采用循环伏安电化学方法对过程中嗜酸氧化亚铁硫杆菌与Fe 3+的催化作用进行了分析。结果表明:嗜酸氧化亚铁硫杆菌和Fe 3+单独或联合都可以有效提高MnO 2浸出Mn 2+的浸出速率,对MnO 2细菌浸出过程有一定催化作用;循环伏安电化学分析表明嗜酸氧化亚铁硫杆菌和Fe 3+单独或联合加入,都会使FeS 2出现明显的氧化还原峰,且嗜酸氧化亚铁硫杆菌可以降低FeS 2的氧化电位和缩短FeS 2氧化峰与还原峰之间的电位差,从而催化MnO 2浸出Mn 2+的过程。 相似文献
3.
Alachlor, atrazine and diuron dissolved in water at 50, 25 and 30 mg/L, respectively were photodegraded by Fe 2+/H 2O 2, Fe 3+/H 2O 2, TiO 2 and TiO 2/Na 2S 2O 8 treatments driven by solar energy at pilot-plant scale using a compound parabolic collector (CPC) photoreactor. All the advanced oxidation processes (AOPs) employed mainly compared the TOC mineralisation rate to evaluate treatment effectiveness. Parent compound disappearance, anion release and oxidant consumption are discussed as a function of treatment time. The use of Fe 2+ or Fe 3+ showed no influence on the reaction rate under illumination and the reaction using 10 or 55 mg/L of iron was quite similar. TiO 2/Na 2S 2O 8 showed a quicker reaction rate than TiO 2 and a similar rate compared to photo-Fenton. The main difference found was between TiO 2/Na 2S 2O 8 and photo-Fenton, detected during atrazine degradation, where pesticide transformation into cyanuric acid was confirmed only for TiO 2/Na 2S 2O 8. 相似文献
4.
采用实验方法研究了低成本环境友好型添加剂抗坏血酸(AA)对Fe 2+/H 2O 2体系氧化NO气体及其对体系内H 2O 2分解的影响,分析了AA对体系氧化NO能力及H 2O 2分解的影响机制。研究结果表明:AA通过加速Fe 3+向Fe 2+的转化而促进Fe 2+/H 2O 2体系对NO的氧化。[AA] 0:[Fe 2+] 0对体系氧化NO的能力及H 2O 2的分解具有重要影响。综合考虑NO氧化脱除量及H 2O 2消耗量,合理的[AA] 0:[Fe 2+] 0为1/3~1/2。AA的分次添加方式可大幅度提升体系氧化NO气体的能力。研究结果可望为发展基于H 2O 2为氧化剂的烟气NO绿色氧化技术提供理论基础。 相似文献
5.
Ta 3N 5 was synthesized by nitridation of Ta 2O 5 under NH 3 flow at 700 °C. The catalyst was pure Ta 3N 5 according to X-ray diffraction (XRD), and was about 5 nm in size with a BET specific surface area 52.8 m 2/g. When Ta 3N 5 was added to Fe 3+/H 2O 2 solution (known as Fenton-like system), most Fe 3+ were adsorbed on the Ta 3N 5 surface and could not react with H 2O 2 in the dark, which is different from the general Fenton reaction. Under visible light irradiation, adsorbed Fe 3+ ions were reduced to Fe 2+ rapidly and Fe 2+ were reoxidized by H 2O 2 on the Ta 3N 5 surface, thus a fast Fe 3+/Fe 2+ cycling was established. Kinetics and ESR measurements supported this mechanism. The Ta 3N 5/Fe 3+/H 2O 2 system could efficiently decompose H 2O 2 to generate hydroxyl radicals driven by visible light, which could accelerate significantly the degradation of organic molecules such as N, N-dimethylaniline (DMA), and 2,4-dichlorophenol (DCP). A mechanism was proposed for iron cycling on the basis of experimental results. 相似文献
6.
为短期快速实现实际生活污水自养脱氮,采用含有厌氧氨氧化菌的实际污水处理厂活性污泥,针对Fe 2+/Fe 3+和Mn 2+对低氧曝气过程中氮的去除效果进行了研究,分析确定了氮素转化的途径。研究结果表明,Fe 2+/Fe 3+和Mn 2+均可提高活性污泥中厌氧氨氧化菌(AnAOB)丰度,但由于Fe 2+/Fe 3+对氨氧化菌(AOB)也存在一定抑制作用,因此,短期投加Fe 2+/Fe 3+条件下,低氧曝气过程中总无机氮去除率为25%,但投加Mn 2+条件下总无机氮去除率可达44%。通过氮素平衡分析,发现投加Fe 2+/Fe 3+条件下,氮素主要通过反硝化作用去除;而投加Mn 2+条件下,氮素主要通过厌氧氨氧化(anammox)作用去除。因此,传统活性污泥可通过短期投加Mn 2+增强厌氧氨氧化活性,促进低氧曝气过程中氮的去除,利于快速实现一体化自养脱氮。 相似文献
7.
The catalytic behavior of the Fe 3+/Fe 2+ system in the electro-Fenton degradation of the antimicrobial drug chlorophene has been studied considering four undivided electrolytic cells, where a Pt or boron-doped diamond (BDD) anode and a carbon felt or O 2-diffusion cathode have been used. Chlorophene electrolyses have been carried out at pH 3.0 under current control, with 0.05 M Na 2SO 4 as supporting electrolyte and Fe 3+ as catalyst. In these processes the drug is oxidized with hydroxyl radical (OH) formed both at the anode from water oxidation and in the medium from electrochemically generated Fenton's reagent (Fe 2+ + H 2O 2, both of them generated at the cathode). The catalytic behavior of the Fe 3+/Fe 2+ system mainly depends on the cathode tested. In the cells with an O 2-diffusion cathode, H 2O 2 is largely accumulated and the Fe 3+ content remains practically unchanged. Under these conditions, the chlorophene decay is enhanced by increasing the initial Fe 3+ concentration, because this leads to a higher quantity of Fe 2+ regenerated at the cathode and, subsequently, to a greater OH production from Fenton's reaction. In contrast, when the carbon felt cathode is used, H 2O 2 is electrogenerated in small extent, whereas Fe 2+ is largely accumulated because the regeneration of this ion from Fe 3+ reduction at the cathode is much faster than its oxidation to Fe 3+ at the anode. In this case, an Fe 3+ concentration as low as 0.2 mM is required to obtain the maximum OH generation rate, yielding the quickest chlorophene removal. Chlorophene is poorly mineralized in the Pt/O 2 diffusion cell because the final Fe 3+–oxalate complexes are difficult to oxidize with OH. These complexes are completely destroyed using a BDD anode at high current thanks to the great amount of OH generated on its surface. Total mineralization is also achieved in the Pt/carbon felt and BDD/carbon felt cells with 0.2 mM Fe 3+, because oxalic acid and its Fe 2+ complexes are directly oxidized with OH in the medium. Comparing the four cells, the highest oxidizing power regarding total mineralization is attained for the BDD/carbon felt cell at high current due to the simultaneous destruction of oxalic acid at the BDD surface and in the bulk solution. 相似文献
8.
利用嗜酸性氧化亚铁硫杆菌将含硫酸亚铁废溶液中的Fe 2+氧化成Fe 3+后用于脱除H 2S,同时实现了含硫酸亚铁废溶液的循环利用和H 2S的脱除。而溶解性Fe 3+较高的生成量是保证该处理系统连续高效运行的关键因素。但在充足氮源和K +条件下大量Fe 3+以黄铁矾沉淀形式存在。因此,本文通过控制氮源种类及投加浓度,减少沉淀生成,增大溶解性Fe 3+生成量,以期提高H 2S的去除效率。结果表明(NH 4) 2HPO 4可替代以往研究中的(NH 4) 2SO 4作为氮源,确定适宜菌体生长的氮源浓度范围为0.33~1 g·L -1。在1 g·L -1 (NH 4) 2HPO 4条件下细菌生长无明显停滞期、Fe 2+平均氧化速率为0.221~0.229 g·(L·h) -1,Fe 3+生成量为7.62~7.72 g·L -1,沉淀量为1.17 g·L -1,因此确定(NH 4) 2HPO 4为1 g·L -1时最能保证H 2S的脱除效率。为降低工艺成本,最低可采用0.33 g·L -1为运行浓度。该优化方案不仅保证了菌体的Fe 2+氧化活性,而且有效地减少了菌体培养过程中沉淀的产生,获得了较高的Fe 3+生成量和增速,为使用含硫酸亚铁废溶液处理H 2S的工艺条件优化提供了依据。 相似文献
9.
The application of metal ion-implantation method has been made to improve the electronic properties of the TiO 2 photocatalyst to realize the utilization of visible light. The photocatalytic properties of these unique TiO 2 photocatalysts for the purification of water have been investigated. By the metal ion-implantation method, metal ions (Fe +, Mn +, V +, etc.) are accelerated enough to have the high kinetic energy (150 keV) and can be implanted into the bulk of TiO 2. TiO 2 photocatalysts which can absorb visible light and work as a photocatalyst efficiently under visible light irradiation were successfully prepared using this advanced technique. The UV-Vis absorption spectra of these metal ion-implanted TiO 2 photocatalysts were found to shift toward visible light regions depending on the amount and the kind of metal ions implanted. They were found to exhibit an effective photocatalytic reactivity for the liquid-phase degradation of 2-propanol diluted in water at 295 K under visible light (λ>450 nm) irradiation. The investigation using XAFS analysis suggested that the substitution of Ti ions in TiO 2 lattice with implanted metal ions is important to modify TiO 2 to be able to adsorb visible light. 相似文献
10.
A cholesterol oxidase (COD) was hybridized with Ca 2+, Zn 2+, Al 3+, Fe 2+ and Mn 2+. After precipitation with PO 43– at 4 °C for 72 h, the resulting pellets were freeze-dried. In scanning electron microscopy assays, the metal-COD complexes revealed flower-like or granular structures after hybridization. Fourier transform infrared spectroscopy assay revealed the characteristic peaks of both the enzyme and metal materials. X-ray diffraction analysis indicated that COD was encapsulated in CaHPO 4·2H 2O-, Zn 3(PO 4) 2·4H 2O-, AlPO 4-, FeP 4- and Mn 3(PO 4) 2·3H 2O-based nanostructures, respectively. Differential scanning calorimetry assay indicated significant increases in thermo-denaturation temperatures from 60.5 °C to 167.02 °C, 167.02 °C, 137.70 °C, 172.85 °C and 160.99 °C, respectively. Using steroid derivatives as substrates, this enzyme could convert cholesterol, pregnenolone, dehydroepiandrosterone, ergosterol, b-sitosterol and stigmasterol to related single products. Hybridization in metal-based nanostructures could significantly enhance the initial conversion ratio and reaction stability of the enzyme. In addition, substrate selectivity could be affected by various metal materials. Briefly, using Ca 2+, Zn 2+, Al 3+, Fe 2+ and Mn 2+ as hybrid raw materials could help to encapsulate COD in related metal-enzyme nanostructures, and could help to promote the stability and tolerant properties of the enzyme, while also enhancing its catalytic characteristics. 相似文献
11.
Acid solutions containing up to 1 g l −1 of the drug paracetamol have been treated with ozone alone and ozonation catalyzed with Fe 2+, Cu 2+ and/or UVA light at 25.0 °C. Direct ozonation yields poor degradation due to the high stability of final carboxylic acids formed, whereas more than 83% of mineralization is attained with the catalyzed methods. Under UVA irradiation, organics can be efficiently destroyed by the combined action of generated H 2O 2 and UVA light. In the presence of Fe 2+ and UVA light, the process is accelerated due to the production of oxidant hydroxyl radical (OH) and the photodecomposition of Fe 3+ complexes. The highest oxidizing power is achieved by combining Fe 2+, Cu 2+ and UVA light, because complexes of final acids with Cu 2+ are more quickly degraded than those competitively formed with Fe 3+. For all catalyzed methods, the initial mineralization rate is enhanced and the percent of degradation generally drops with increasing drug concentration. The paracetamol decay always follows a pseudo-first-order reaction with slightly higher rate constant for catalyzed systems than direct ozonation. Aromatic products such as hydroquinone, p-benzoquinone and 2-hydroxy-4-( N-acetyl)aminophenol are identified by gas chromatography–mass spectrometry (GC–MS) and reversed-phase chromatography. Acetamide is generated when hydroquinone is produced. These products are degraded to oxalic and oxamic acids as ultimate carboxylic acids, as detected by GC–MS and ion-exclusion chromatography. Oxalic acid is generated via glycolic, glyoxylic, tartronic, ketomalonic and maleic acids. While Fe 3+-oxalato complexes are photolyzed by UVA light, Cu 2+-oxalato, Fe 3+-oxamato and Cu 2+-oxamato complexes are oxidized with OH. NH 4+ and NO 3− ions are produced during mineralization. 相似文献
12.
采用二(2-乙基己基)磷酸酯(P204)-磺化煤油萃取体系从高硫酸氰化尾渣矿浆电解液中富集铁离子,重点研究了P204浓度、相比(O/A)、振荡时间、振荡频率及温度等对Fe 3+萃取率的影响及其萃取过程。研究表明,在P204体积分数为25%、电解液pH为1.5、温度25℃、O/A=1∶1、振荡时间10 min、振荡频率180r/min的条件下,电解液中Fe 3+的单级萃取率可达97.73%以上,饱和萃取容量可达到21.57g/L。Fe 3+在有机相中的萃取富集主要归因于其与P204分子结构中羟基的阳离子交换反应以及磷酰基的配位反应,形成的配合物为FeSO 4A(HA) 3与FeA 3(HA) 3。在草酸1mol/L、O/A=1∶1、振荡时间10min、振荡频率190r/min的条件下,负载有机相中Fe 3+的单级反萃率可达82.64%以上,反萃液中铁主要以[Fe(C 2O 4) 3<... 相似文献
13.
The photo-assisted Fenton degradation of salicylic acid (SA) was studied by using strongly acidic ion exchange resin (SAIER) exchanged with Fe ions as catalyst in the presence of UV light (254 nm) and H 2O 2. The X-ray photoelectron spectroscopy (XPS) results revealed that the Fe ions are indeed anchored by the sulfonate groups on the surface of the SAIER and are Fe 3+. Our results also indicate that the Fe/SAIER catalyst can significantly enhance the degradation rate of SA without remarkable Fe leaching to the solution, implying that the catalyst has photo-catalytic activity. In addition, the effects of [H 2O 2]/[SA] molar ratio, UVC light power, solution pH, catalyst loading, and initial SA concentration on the degradation of SA were investigated in detail. 相似文献
14.
Field disinfection of water in a large solar compound parabolic collector (CPC) photoreactor (35–70 l) was conducted at 35 °C by different photocatalytic processes: sunlight/TiO 2, sunlight/TiO 2/Fe 3+, sunlight/Fe 3+/H 2O 2 and compared to the control experiment of direct sunlight alone. Experiments were carried out using a CPC and natural water spiked with E. coli K 12. Under these conditions, total disinfection by bare sunlight irradiation was not reached after 5 h of treatment; and bacterial recovery was observed during the subsequent 24 h in the dark. The addition of TiO2, TiO2/Fe3+ or Fe3+/H2O2 to the water accelerates the bactericidal action of sunlight, leading to total disinfection by solar-photocatalysis. No bacterial regrowth was observed during 24 h after stopping sunlight exposure. For some samples, the decrease of bacteria continues in the dark. A “residual disinfection effect” was observed for these samples before reaching the total inactivation. The effective disinfection time (EDT24), defined as the treatment time required to prevent any bacterial regrowth during the subsequent 24 h in the dark, after stopping the phototreatment, was reached in the presence but not in the absence of different photocatalytic systems. EDT24 was 2 h 30 min, 2 h and 1 h 30 min for sunlight/TiO2, sunlight/TiO2/Fe3+ and sunlight/Fe3+/H2O2 systems, respectively. The post irradiation events observed when the phototreated water is poured into an optimal growth medium are also discussed. 相似文献
15.
针对铁碳微电解(Fe 0/GAC)-Fenton法降解硝基苯(NB)废水时难连续运行的问题,采用超声(US)强化铁碳微电解-Fenton法降解硝基苯废水。考察了超声对铁碳微电解-Fenton法连续运行效果的影响,研究表明:不更换铁碳填料时,Fe 0/GAC-Fenton法连续处理4批硝基苯废水时,硝基苯去除率从69.54%降至31.66%,TOC去除率也从48.11%降至19.20%;而US/Fe 0/GAC-Fenton法处理4批相同废水时,硝基苯去除率均近至100%,TOC去除率均稳定在60%以上。与单纯Fe 0/GAC-Fenton相比,超声不仅整体上强化了Fe 0/GAC-Fenton法降解硝基苯废水的效率,还实现了连续多次高效运行。研究了pH、H 2O 2投加量及投加次数对Fenton法降解US/Fe 0/GAC出水的影响规律,得到适宜操作条件:H 2O 2总投加量为4 ml并分5次添加,US/Fe 0/GAC的出水pH调为4,反应30 min,最终硝基苯去除率达到100%,TOC去除率可达75%。 相似文献
16.
具有复杂分子结构的三苯甲烷类染料孔雀石绿是一种典型的较难降解染料,是工业废水处理的难点之一。本文根据Goldschmidt半径容差规则法,设计了用于孔雀石绿降解的ABO 3型SrFe (1-x)Co xO 3催化剂,并选择出活性较高的SrFe 0.6Co 0.4O 3催化剂。通过XRD、SEM、BET吸附及XPS分析表明:该催化剂是纯净钙钛矿结构,颗粒形貌为无规则堆叠的“蜂窝”片状;吸附等温线没有明显的回滞环,说明没有“墨水瓶”类孔结构;XPS谱中,B位离子同时存在Fe 2+/Fe 3+和Co 2+/Co 3+ 4种价态离子,且反应前后,4种离子的分布比例有较大变化。根据实验结果,推测该催化反应机理为:催化剂B位Co 3+与溶解氧形成活性氧[O 2] +和Co 2+;活性氧[O 2] +完成氧化反应后其正电荷转移到B位Fe 2+上形成Fe 3+,Fe 3+的正电荷可再转移到Co 2+形成Co 3+,完成催化过程的电荷转移与循环。 相似文献
17.
Atomic layer epitaxy (ALE), a technique relying on saturating gas–solid reactions, was applied in the preparation of CrO x/Al 2O 3 catalysts using Cr(acac) 3 vapor and air as source materials for CrO x. Vaporized Cr(acac) 3 was reacted with preheated Al 2O 3, and the surface complex formed was treated with air to remove the ligand residues. The Cr loading increased from 1.3 to 12.5 wt.% as the number of saturating Cr(acac) 3 and air reactions was increased from one to 10. CrO x/Al 2O 3 catalysts were also prepared from solution by incipient wetness impregnation (0.3–21 wt.%). XPS and UV–VIS measurements of the catalysts revealed the presence of both Cr 6+ and Cr 3+. Although the oxidation state distribution was similar, H 2-temperature programmed reduction (TPR) and solubility measurements indicated that Cr 6+ surface sites were in stronger interaction with Al 2O 3 and more uniformly distributed in the catalysts prepared by ALE than by impregnation. On the basis of the activity of the catalysts in the dehydrogenation of i-butane, we propose that the dehydrogenation reaction uses both reduced Cr 6+, i.e. redox Cr 3+, and exposed non-redox Cr 3+ sites. Furthermore, the dehydrogenation reaction must be insensitive to the size of the CrO x ensembles since activities were similar for the catalysts prepared by ALE and impregnation. The decay of the dehydrogenation activity in successive prereduction–reaction–regeneration cycles was attributed to a decrease in the number of redox Cr 3+ sites. 相似文献
18.
Fe 2+的再生直接决定Fenton体系产生的能力。选取羟胺、对苯二酚、对苯醌、亚硫酸钠4种典型添加剂,通过分析不同改性Fenton体系中Fe 2+浓度、H 2O 2浓度、氧化还原电极电位(ORP),揭示了Fe 2+再生机制的差异,并进一步分析了不同添加剂与体系中H 2O 2及·OH的反应情况。结果表明:NH 2OH能快速使Fe 2+再生,但伴随其消耗,Fe 2+浓度不断降低。对苯二酚、对苯醌具有相似效果,两者均可大大强化Fe 2+的再生。与NH 2OH不同,两者在体系中可迅速建立醌循环,持续还原Fe 3+,且以两种物质或其组合均可建立循环。与上述机理均不同,Na 2SO 3会先与·OH及H 2O 2反应,因而不能有效还原Fe 3+。实验还发现添加剂均存在与·OH的反应,其中Na 2SO 3还会消耗H 2O 2。 相似文献
19.
With an aim to improve the 5 V capacity and cyclability of the LiMn 1.5Ni 0.5O 4 spinel oxide, three series of Cr substitutions have been pursued with y ≤ 0.2: LiMn 1.5Ni 0.5−yCr yO 4, LiMn 1.5−0.5yNi 0.5−0.5yCr yO 4, and LiMn 1.5−0.33yLi 0.33yNi 0.5−yCr yO 4. While the first series involves an increase in the Mn 3+ content, the second and third series are designed to maintain charge neutrality (Mn 4+, Ni 2+, Cr 3+, and Li +) without introducing Mn 3+ ions. The LiMn 1.5Ni 0.5−yCr yO 4 series experiences a widening of the 4 V plateau and a decrease in the 5 V capacity compared to LiMn 1.5Ni 0.5O 4 due to an increase in the Mn 3+ content. On the other hand, the LiMn 1.5−0.5yNi 0.5−0.5yCr yO 4 series shows a suppression of the 4 V plateau and an increase in the 5 V capacity due to the elimination of the Mn 3+ions. The LiMn 1.5−0.33yLi 0.33yNi 0.5−yCr yO 4 series shows a suppression of the 4 V plateau at low Cr contents, but an increase in the 4 V plateau as the Cr content increases above 0.1. Among the various compositions investigated, LiMn 1.45Ni 0.45Cr 0.1O 4 exhibits the best combination of high 5 V capacity (128 mAh/g at 5–4.2 V) and excellent capacity retention (98% in 50 cycles) compared to 118 mAh/g and 92% for LiMn 1.5Ni 0.5O 4. 相似文献
20.
In this work, a combinatorial methodology was developed for photodegradation catalyst screening. A fluorescence imaging detection system was designed for high throughput analysis, 1,6-hexamethylenediamine was used as the probe molecule for catalyst testing. The photodegradation activity of catalysts was evaluated by 1,6-hexamethylenediamine consumption during the photodegradation reaction. The methodology could provide reliable results. We found that pure TiO 2, ZrO 2, Nb 2O 5, MoO 3, and WO 3 did not show much activity for 1,6-hexamethylenediamine photodegradation under visible light. TiO 2 catalysts doped with different metal ions were tested. When TiO 2 was doped with Ta 2O 5, Nb 2O 5, V 2O 5, MoO 3, or WO 3, higher activity for photodegradation was observed. The doping of La 3+, Ba 2+, and Br − to TiO 2 did not improve the catalytic activities. When doping TiO 2 with Mn 2+, Cl −, Al 3+, Cu 2+, Fe 3+, Na +, Mg 2+, Li +, F −, Co 2+, or K +, catalytic activity was lower than that of pure TiO 2. After elaborate catalysts screening, we discovered new catalysts, such as 50–70% TiO 2/0–20% WO 3/20–40% VO 2.5 and 20–30% TiO 2/30–50% MoO 3/40–60% VO 2.5 as well as 30% WO 3/20% ZrO 2/50% NbO 2.5 (synthesized from ZrCl 4, NbCl 5, and (NH 4) 5H 5[H 2(WO 4) 6]·H 2O in ethanol solution or suspension) and 60–70% WO 3/Nb 2O 5 (synthesized from WCl 6 and NbCl 5 in ethanol solution). We observed that the catalytic activity is sensitive to preparation methods and catalyst specific surface areas. When P123 (HO(CH 2CH 2O) 20(CH 2CH(CH 3)O) 70(CH 2CH 2O) 20H, designated EO 20PO 70EO 20) was used as template to synthesize mesoporous materials, the mesoporous catalysts showed higher activity than regular catalytic materials. 相似文献
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