不同载体的TiO2光催化剂降解亚甲基蓝动力学研究

分别以活性炭(AC)和色氨酸(L-Trp)作为两种不同类型载体,通过溶胶-凝胶法制得TiO₂/AC和TiO₂/L-Trp光催化剂,比较了两种载体对亚甲基蓝(MB)吸附和光降解反应的性能影响,分析了其反应机理,并对光催化剂进行了表征分析。实验结果表明,TiO₂/AC和TiO₂/L-Trp的最优煅烧温度均为550℃,最优用量均为1 g/L。表征结果表明,TiO₂/AC和TiO₂/L-Trp均负载了以锐钛矿型存在的TiO₂,TiO₂/AC比表面积大于TiO₂/L-Trp。动力学拟合结果表明TiO₂/AC和TiO₂/L-Trp光催化剂光降解MB受其扩散步骤控制。     

基于ZIF的Ce掺杂ZnO光催化剂催化降解亚甲基蓝废水研究

以硝酸锌、二甲基咪唑(制备沸石咪唑酯骨架结构材料(ZIF)的主要原料)、以及硝酸铈等制备了Ce掺杂的Zn O光催化剂(即Ce-ZnO),对催化剂进行了XRD,SEM,EDS等表征分析,考察了Ce掺杂量、废水初始pH等对亚甲基蓝降解影响,用UV-Vis(可见-紫外光谱)对亚甲基蓝降解液进行了分析。研究表明,与ZIF为前驱体的Zn O的形貌和晶体结构类似,Ce掺杂的Zn O催化剂仍为方形颗粒微纳米材料(颗粒尺寸约100 nm)、Zn O为六方晶系纤锌矿结构,但颗粒尺寸减小。掺杂1%的Ce可使Zn O的光催化剂活性提高(光催化剂降解亚甲基蓝的反应速率提高了31%),且具有较好的重复利用性能。Ce-ZnO光催化剂催化降解亚甲基蓝的反应符合一级反应动力学,弱碱性(pH≈10)环境有利于亚甲基蓝光催化剂降解,亚甲基蓝在光催化反应中其显色基团、芳香基团被分解并产生了酸性物质,亚甲基蓝被有效降解。     

纳米CuO/CoFe2O4-TiO2模拟太阳光降解亚甲基蓝的性能

采用溶胶-凝胶法制备CuO/CoFe2O4粒子,并与P25复合制备纳米催化剂CuO/CoFe2O4-TiO2.通过模拟太阳光催化降解亚甲基蓝,对催化剂活性进行研究,采用SEM、TEM、XRD和UV-Vis DRS方法对催化剂进行表征.结果表明,CuO/CoFe2O4粒子均匀分散在P25微粒表面,平均粒径为60 nm.并...     

ZnO掺杂TiO_2可见光催化降解亚甲基蓝的研究

选取亚甲基蓝染料为降解目标物,研究了ZnO掺杂TiO2为催化剂的可见光催化反应,重点考察了ZnO的掺杂量、催化剂的添加量、溶液初始浓度、光照时间、溶液pH值对降解效率的影响。实验结果表明,在ZnO掺杂比为0.5%、ZnO掺杂TiO2的催化剂用量为10g/L、pH为8、浓度为2mg/L的亚甲基蓝100mL,白炽灯光照降解...     

热处理温度对La-TiO_2光催化降解亚甲基蓝的影响

La-TiO_2热处理温度分别为350℃、550℃和750℃,热处理时间1 h,采用红外光谱和紫外-可见分光光度计等研究热处理温度对La-TiO_2光催化性能的影响。结果表明,热处理的LaTiO_2对亚甲基蓝的光催化降解过程符合一级动力学模型,550℃热处理的La-TiO_2光催化活性最高,光催化反应动力学常数k=0.002 201 min-1。     

超声-S/TiO_2纳米颗粒可见光催化协同降解亚甲基蓝

采用共沉淀-浸渍法制备掺杂S的TiO2光催化剂,利用XRD,TEM,UV-Vis-DRs,XPS等方法对其结构、元素组成和光谱学特征进行研究,以亚甲基蓝(MB)的光催化降解反应为模型,探讨高效利用可见光降解亚甲基蓝的反应体系。实验结果表明,S掺杂最佳热处理温度为500℃。掺杂光催化剂晶型仍为锐钛矿型,其粒径变小,比表面积增大,热稳定性增加,对可见光的吸收增强。超声波对光催化降解反应有协同作用,S/TiO2在可见光下对亚甲基蓝的降解率明显高于纯TiO2。     

掺锌纳米TiO2光催化降解亚甲基蓝研究

摘要：选用掺杂锌的纳米TiO2作为光催化剂对亚甲基蓝进行降解研究。制备工艺参数对样品光催化降解亚甲基蓝的活性具有很大影响,焙烧温度为500oC,Zn2＋掺入量为0．5％,催化剂的加入量为1g／L时光催化剂对亚甲基蓝的降解效果最好;亚甲基蓝的初始浓度为5mg／L降解速率较快。     

掺锌纳米TiO_2光催化降解亚甲基蓝研究

选用掺杂锌的纳米TiO2作为光催化剂对亚甲基蓝进行降解研究。制备工艺参数对样品光催化降解亚甲基蓝的活性具有很大影响,焙烧温度为500℃,Zn2+掺入量为0.5%,催化剂的加入量为1 g/L时光催化剂对亚甲基蓝的降解效果最好;亚甲基蓝的初始浓度为5 mg/L降解速率较快。     

不同光源对光催化降解亚甲基蓝的影响

用长弧氙灯、中压汞灯、高压汞灯、镓灯、镝灯等几种光源对光催化降解亚甲基蓝的效果进行了比较。结果证明镓灯的效果最好 ,其降解速率高于其它光源 ,所得到的反应速率常数是常用中压汞灯的 1 .2 4倍。从光子对Ti O2 的作用机理及光谱分析结果可以证明 ,光源的紫外部分辐射强度愈高对反应愈有利。并为光催化反应中光源的选择提供了一定的依据。     

二氧化钛溶胶日光下降解亚甲基蓝的研究

以自制TiO2溶胶为光催化剂,采用日光作为光源,研究了亚甲基蓝水溶液被光催化降解的各种影响因素.实验结果表明,TiO2溶胶光催化活性较高,在选定的实验条件下,对一定浓度的亚甲基蓝溶液降解率可达到80%以上.     

Fe2O3-SnO2纳米光催化剂模拟日光下降解酸性蓝废水

用共沉淀法合成了Fe2O3-SnO2纳米复合氧化物光催化剂,并利用多种表征手段进行了表征。以酸性蓝染料溶液为模拟废水,在氙灯(模拟日光)光照下,对Fe2O3-SnO2纳米复合氧化物的光催化活性进行了评价。     

亚甲基蓝溶液的光催化降解

采用三种不同方法对TiO2粉末进行改性,制得蒙脱土/TiO2、Ag/TiO2和SO42-/TiO2催化剂。以亚甲基水蓝溶液的脱色率为指标,采用XRD、SEM和XPS等手段分析考察了3种改性催化剂的活性及抗无机离子的干扰能力。结果显示,三种改性光催化剂在溶液中的活性顺序为：蒙脱土/TiO₂>SO₄^2-/TiO₂>Ag/TiO₂>TiO₂。其中,蒙脱土/TiO2活性提高最大,在温度30 ℃和催化剂用量1.0 g·L^-1条件下,1 h内使 5.0 mg·L^-1的亚甲基蓝溶液的脱色率达90%以上,Ag/TiO₂的抗无机离子干扰能力最强。     

Photocatalytic degradation of PCP-Na over BiOI nanosheets under simulated sunlight irradiation

The photocatalytic removal of sodium pentachlorophenate (PCP-Na) over BiOI nanosheets under simulated solar light irradiation has been studied. BiOI nanosheets exhibited an excellent photocatalytic activity to remove PCP-Na from aqueous solution driven by simulated light. The photocatalytic reaction over BiOI nanosheets followed the pseudo first-order reaction, owning to its weak adsorption behavior to PCP-Na molecules and low initial PCP-Na concentration. Finally, the photocatalytic mechanism was investigated initially on the basis of the experimental result and band edge potential analysis.     

Photocatalytic degradation of cationic blue X-GRL adsorbed on TiO2/SiO2 photocatalyst

Photocatalytic degradation of cationic blue X-GRL (CBX), a strongly adsorbing substrate on TiO₂/SiO₂, has been investigated by diffuse reflection UV–VIS spectra (UV–visible/DRS) and FT-IR methods. The heterogeneous photocatalysis processes include: adsorption of dye, surface reaction and desorption of final products. The adsorption of CBX onto the surface of TiO₂/SiO₂ was characterized, and the effect of initial pH of solution on the adsorption was determined. The results demonstrated that CBX was strongly adsorbed at the TiO⁻ site of the catalyst by a penta-heterocyclic-N group. The adsorbed CBX was monitored directly by the UV–VIS/DRS technique during the photodegradation. The results confirmed that the surface photodegradation reaction of CBX was predominantly procedure with the mechanism of direct charge transfer from the semiconductor to the dye adsorbed at TiO center, and its reaction followed the pseudo-first-order kinetics. This mechanism resulted in the formation of more aliphatic amines and/or amide byproducts, which were further transformed to NH₄⁺.     

Cu_2O掺杂TiO_2光催化降解亚甲基蓝的研究

以钛酸四丁酯和乙酸铜为原料,柠檬酸和葡萄糖作还原剂,采用水解法制备了Cu_2O/TiO_2复合光催化剂,并通过XRD和SEM表征手段进行了表征。以Cu_2O/TiO_2为光催化剂,考察了反应时间、初始浓度、催化剂用量、起始pH和温度等因素对光催化降解亚甲基蓝脱色率的影响。结果表明,在高压汞灯照射下,以0.01 g Cu_2O/TiO_2为光催化剂,以100 mL 10 mg/L亚甲基蓝溶液为模拟废水,pH为7.0,25℃下光催化反应60 min,亚甲基蓝脱色率可以达到94.38%,其脱色动力学反应为准一级过程。     

Photocatalytic activity of AgBr/TiO2 in water under simulated sunlight irradiation

In this paper, the synthesis of AgBr/TiO₂ catalyst and the photocatalytic activity in water under simulated sunlight irradiation were studied. The influence of AgBr content in catalyst and the incident light intensity on the degradation of methyl orange (MO) was investigated. It was found that the initial reaction rate constant was dependent on the relative levels of AgBr content and incident light intensity, ranging between 0.008 min⁻¹ and 0.023 min⁻¹. At higher levels of AgBr content (>9 wt%), MO degradation was exclusively dependent on the incident light intensity, which implied that the excessive AgBr in catalyst had negligible effect on catalyst activity. However, at lower AgBr contents, the reaction rate increased with the increase of incident light intensity, and eventually reached a plateau level, indicating that the degradation of MO was limited by AgBr content. The results from powder X-ray diffraction (XRD) analysis showed that more than 80% of AgBr remained intact after 14 h of irradiation, although metallic silver was also detected.     

Photodegradation of methylene blue with a titanium dioxide/polyacrylamide photocatalyst under sunlight

Hydrogels containing TiO₂ nanoparticles (NPs) have photocatalytic properties and degrade pollutants under light. In this study, a polyacrylamide (PAAm) hydrogel was synthesized with TiO₂ P25 NPs as the initiator, acrylamide as a monomer, and N,N′‐methylene bisacrylamide as a crosslinker in aqueous media under sunlight. Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy were applied to characterize the TiO₂/PAAm hydrogel. The effects of different synthetic conditions, such as the initiator concentration, crosslinker, and dilution, on swelling were investigated. The maximum swelling of the TiO₂/PAAm hydrogel was 45 g/g in the hydrogel synthesized with optimum conditions by 0.2% TiO₂. The photocatalytic degradability of the hydrogel was investigated with methylene blue (MB) as the pollutant target. Also, the effects of the pH and MB concentration were studied. Under optimum conditions, 95.00% of the MB was degraded by the TiO₂/PAAm photocatalyst after 5 h of irradiation under sunlight. The comparison of the results with those of the TiO₂ P25 powder showed that the TiO₂ NPs had better activity than the hydrogel, but unlike the hydrogel, the activity of these NPs decreased in each recycling time because of the aggregation of NPs. Finally, the hydrogel was recycled seven times without a considerable reduction in the degradation efficiency. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43386.     

Photocatalytic degradation of methylene blue and sulfisoxazole from water using biosynthesized zinc ferrite nanoparticles

The extensive occurrence of textile and pharmaceutical contaminants and their metabolites in water systems has posed significant concerns regarding their possible threat to human health and the environmental system. As a result, herein ZnFe₂O₄ nanoparticles were synthesized through the use of Monsonia burkeana plant extract. The synthesized nanoparticles were characterized using XRD, FTIR, UV–vis, SEM, EDS, TGA, BET, PL, EPR and VSM. XRD showed that the crystalline structure of ZnFe₂O₄ nanoparticles with a calculated crystal size of 25.03 nm was formed. FT-IR confirmed the characteristic functional groups contained within the M. burkeana plant were deposited on the formed ferrite nanoparticles. BET analysis confirmed the mesoporous nature of ZnFe₂O₄ with an average pore diameter of 31.6 nm. Morphological studies demonstrated that the formed nanoparticles had spherical as well as rod-like shapes. ZnFe₂O₄ photocatalyst illustrated that it may be effortlessly detached by an external magnetic field. The optimum conditions for the 99.8% removal of Methylene Blue was obtained at pH12, within 45min and at the optimum dosage of 25 mg of the catalyst. The as-prepared ZnFe₂O₄ nanoparticles proved to be easily separated and recycled, and remained efficient even after 5 reuses, proving that the material is highly stable. The ROS studies also demonstrated that electrons are the main factors contributing to the degradation of MB. Upon testing the photocatalytic performance of the sulfonamide antibiotic, sulfisoxazole in water showed a degradation of 67%. This study has shown that these materials can be used in targeting textile and pharmaceutically polluted water.