二氧化硅负载碘氧化铋光催化降解甲基橙性能研究

采用沉淀-浸渍法制备了不同负载量的二氧化硅负载碘氧化铋催化剂，考察了其光催化降解甲基橙性能。采用XRD、UV-Vis、TEM对催化剂进行了表征。结果表明，随着碘氧化铋负载量的增加，二氧化硅负载碘氧化铋催化剂光催化降解甲基橙的降解率升高。当碘氧化铋和二氧化硅的物质的量比为0.5时，二氧化硅负载碘氧化铋催化剂降解甲基橙的降解率60 min时可达73.74%。不同粒径二氧化硅负载的碘氧化铋催化剂对甲基橙的降解率接近，因为活性组分碘氧化铋都可以高度分散在不同粒径的二氧化硅载体上。     

纳米TiO_2/硅藻土复合材料光催化降解甲基橙的研究

以提纯硅藻土为载体原料,钛酸四丁酯为TiO_2前驱体,采用溶胶-凝胶法制备纳米TiO_2/硅藻土复合材料。通过XRD、SEM对复合材料晶型结构和形貌表征分析,以甲基橙为目标污染物,考察复合材料对甲基橙光催化性能影响。结果表明,TiO_2负载量为37.67%制备的复合材料光催化活性最好,TiO_2为锐钛矿和金红石混晶型。甲基橙溶液初始浓度为10 mg/L,催化剂用量为2 g/L,pH=2时,甲基橙溶液降解效果最好。     

纳米TiO_2/硅藻土复合材料光催化降解甲基橙的研究

以提纯硅藻土为载体原料,钛酸四丁酯为TiO_2前驱体,采用溶胶-凝胶法制备纳米TiO_2/硅藻土复合材料。通过XRD、SEM对复合材料晶型结构和形貌表征分析,以甲基橙为目标污染物,考察复合材料对甲基橙光催化性能影响。结果表明,TiO_2负载量为37.67%制备的复合材料光催化活性最好,TiO_2为锐钛矿和金红石混晶型。甲基橙溶液初始浓度为10 mg/L,催化剂用量为2 g/L,pH=2时,甲基橙溶液降解效果最好。     

SO2-4/Fe2O3固体超强酸的制备及光催化降解甲基橙的研究

采用沉淀-浸渍法制备SO2-4/Fe2O3固体超强酸催化剂.通过单因素实验考察了SO2-4/Fe2O3光降解甲基橙的效果.结果表明,固体超强酸SO2-4/Fe2O3光催化降解甲基橙的最优反应条件是:溶液pH值为6,催化用量2g·L-1,甲基橙溶液初始浓度10mg·L-1,反应时间90min.在最优反应条件下,甲基橙的降解率可达90％以上.     

BiOI/g-C3N4光催化降解甲基橙研究

以三聚氰胺为前驱物采用热聚合法制备了石墨相氮化碳（g-C₃N₄）,并在其表面原位合成了碘氧化铋（BiOI）,构筑了石墨相氮化碳-碘氧化铋复合材料。采用X射线衍射仪（XRD）、傅里叶变换红外光谱仪（FT-IR）、紫外可见漫反射仪（UV-Vis-DRS）等对催化剂进行了表征。结果表明,当BiOI与g-C₃N₄物质的量比为0.5时,BiOI/g-C₃N₄催化剂具有高分散的BiOI颗粒及适中的禁带宽度,吸附和降解甲基橙性能最佳。回流温度为120 ℃时制备的BiOI/g-C₃N₄催化剂具有适中的粒径、比表面积和表面羟基浓度,吸附和降解甲基橙性能最佳,且该催化剂具有良好的重复使用性能。     

Multiple-metal-doped Fe3O4@Fe2O3 nanoparticles with enhanced photocatalytic performance for methyl orange degradation under UV/solar light irradiation

Waelz slag, which is a Fe-bearing hazardous waste, was applied as the raw material in the synthesis of M-Fe₃O₄@Fe₂O₃ (M = Al, Zn, Cu, and Mn) nanoparticles, which are potential photocatalysts. Through acidolysis, 97.23% of Fe and most of the valuable metals were extracted from this slag. Using sol-gel processes, designed Fe₃O₄@Fe₂O₃ nanoparticles doped with multiple elements were systematically synthesised and characterised using X-ray diffraction, field emission scanning electron microscopy, electron diffraction spectroscopy, transmission electron microscopy, and Brunauer–Emmett–Teller analysis. The photocatalytic activities of the synthesised particles and undoped Fe₂O₃ nanoparticles were compared through photocatalytic methyl orange degradation experiments under UV and simulated solar light. The results indicated that all of the slag-derived nanoparticles gave improved photocatalytic performances compared to the undoped sample, and the M-Fe₃O₄@Fe₂O₃ (M = Al, Zn, and Cu) sample exhibited the best photocatalytic activity. The enhancement can be attributed to grain refinement, doping, and the formation of a typical Fe₃O₄@Fe₂O₃ core-shell structure.     

H4SiW12O40/TiO2-ZrO2的制备及光催化降解甲基橙的研究

采用浸渍法制备了H4SiW12O40/TiO2-ZrO2光催化剂,以光催化降解染料废水甲基橙为探针反应,探讨了催化剂投加量、溶液pH值对光催化降解效果的影响以及催化剂的重复使用性。结果表明,H4SiW12O40/TiO2-ZrO2催化剂具有更优越的光催化性能,当催化剂的用量为1.8 g/L,甲基橙溶液初始浓度为10 mg/L,pH=4时,反应4 h后甲基橙的降解率可达90%以上。     

Synthesis of oxygen deficient BiOI for photocatalytic degradation of methyl orange

Oxygen defects are introduced into BiOI by a simple glycerol treatment. This deficient BiOI demonstrated 3.5 times higher photocatalytic performance than the untreated BiOI nanosheets for methyl orange (MO) degradation under visible light irradiation. Moreover, the deficient BiOI nanosheets have excellent cycling stability. The improved efficiency can be ascribed to the significantly enhanced separation efficiency of photogenerated and utilized more solar light.     

掺钇纳米二氧化钛光催化降解甲基橙的研究

采用金属钇掺杂改性,以钛酸四丁酯为主要原料,在室温下,利用溶胶-凝胶法制备了Y3+掺杂纳米TiO2光催化剂,通过X射线衍射分析(XRD)方法分析其改性机制;掺钇纳米TiO2光催化剂经太阳光照射后,用分光光度计测量光催化降解反应后甲基橙溶液浓度的变化,考察其光催化活性;研究了掺杂量和焙烧温度对光催化活性的影响。结果表明,Y3+掺杂能有效地抑制锐钛矿型TiO2向金红石型TiO2的转化,可使纳米TiO2的衍射峰宽化,粒径从80.5 nm降低到42.15 nm,掺杂量为1.2%,焙烧温度在400℃左右时,能够有效地提高TiO2光催化剂光催化活性。     

Chiral induction enhanced photocatalytic degradation of methyl orange by Ag@Ag3PO4 and the reaction mechanism

A novel chiral Ag@Ag₃PO₄-NaDC composite was synthesized by chiral induction. SEM, XRD, CD spectrum, FTIR, UV–vis and XPS were used to study the physical and chemical properties of the materials, and the photocatalytic oxidation ability was evaluated with methyl orange as the target pollutant. The results show that the introduction of chirality can obviously promote the light absorption ability, broaden the band gap, enhance the oxidation ability, promote the separation of electrons and holes, greatly enhance the plasma resonance effect of silver nanoparticles, and promote the synergistic effect between silver nanoparticles and silver phosphate. Compared with Ag@Ag₃PO₄, the catalytic degradation ability of chiral Ag@Ag₃PO₄-NaDC is improved by more than 60%. Therefore, the chiral Ag@Ag₃PO₄-NaDC composite exhibits excellent photocatalytic performance. In the degradation of methyl orange by Ag@Ag₃PO₄-NaDC, a large amount of ·O₂^- and h⁺ were formed on the surface, which was the main reason for the oxidation ability.     

Preparation of thermosensitive and visible‐light responsible composites based on hydrogels of N‐isopropylacrylamide/maleic anhydride‐modified β‐cyclodextrin copolymer and TiO2/multiwalled carbon nanotubes particles for degradation of methyl orange

The novel thermosensitive and visible‐light responsible composites composed of poly(N‐isopropylacrylamide‐co‐maleic anhydride modified β‐cyclodextrin) hydrogels (poly(NIPAM‐co‐MAH‐β‐CD)) and TiO2 doped with multiwalled carbon nanotubes (TiO2‐MWCNTs) were prepared by an aqueous solution polymerization method with N,N′‐methylenebisacrylamide as crosslinker, potassium persulfate as initiator, NIPAM and MAH‐β‐CD as monomers, and TiO2‐MWCNTs as functional filler. The structure and properties of the as‐prepared thermosensitive composites were characterized with FTIR, XRD, XPS, TEM, BET, and UV‐vis diffuse reflectance spectroscopy. The thermoresponsive property of the composites prepared under various synthesis conditions was investigated using equilibrium swelling ratio measurements at temperatures ranging from 20 to 45°C. The swelling mechanism and kinetics of the composites were determined by analyzing the rate of swelling. The photocatalytic behavior of the thermosensitive composites was evaluated from the extent of removal of methyl orange (MO) from solutions under solar light irradiation. It was found that the thermosensitive composites have better removal efficiency of MO than pure TiO2. The thermosensitive composites exhibited easy separation and less deactivation after several runs. The advantages of the thermosensitive composites revealed its great practical potential in wastewater treatment. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Synthesis of TiO2 nano-particles and their photocatalytic activity for formaldehyde and methyl orange degradation

TiO₂ nano-particles were synthesized by sol-gel technique and characterized by X-ray diffractometer (XRD) and transmission electron microscope (TEM). Their photocatalytic activities for formaldehyde (FA) and methyl orange (MO) degradation were tested using degradation rate (η) as an evaluation index. Based on the orthogonal test results, the optimal condition for TiO₂ preparation was obtained. Results showed that particle sizes were in the range of 10–40 nm, and that prepared TiO₂ had better photocatalytic activity than P25. A simplified model was developed to evaluate the apparent quantum efficiency (Φ _app) of this photocatalytic reaction system.     

Zn掺杂TiO2的制备及其光催化降解甲基橙性能

采用沉淀法制备了不同掺杂量的Zn/TiO₂催化剂,以光催化降解甲基橙为探针反应,考察其光催化活性,并采用紫外漫反射和X射线衍射对其进行结构表征。研究结果表明,Zn的掺杂量对催化剂活性影响较大,最佳掺杂物质的量分数为1.5%;催化剂的紫外漫反射微分曲线的峰值变化与其活性变化一致,1.5%(物质的量分数) Zn/TiO2的微分峰值最大。X射线衍射分析表明,少量Zn高度分散在TiO₂晶格中。Zn掺杂物质的量分数1.5%时,添加2 g·L^-1的Zn/TiO₂催化剂,甲基橙降解的最佳条件：pH＝3,浓度15 mg·L^-1,降解率最高达98.6％。     

SO2-4/Fe2O3固体超强酸的制备及光催化降解甲基橙的研究

采用沉淀-浸渍法制备SO2-4/Fe2O3固体超强酸催化剂.通过单因素实验考察了SO2-4/Fe2O3光降解甲基橙的效果.结果表明,固体超强酸SO2-4/Fe2O3光催化降解甲基橙的最优反应条件是:溶液pH值为6,催化用量2g·L-1,甲基橙溶液初始浓度10mg·L-1,反应时间90min.在最优反应条件下,甲基橙的降...     

Hydrothermal synthesis of S-doped TiO2 nanoparticles and their photocatalytic ability for degradation of methyl orange

A simple synthesis route to nanocrystalline S-doped TiO₂ photocatalysts by a hydrothermal method at 180 °C was developed and the photocatalytic activity of the obtained powders for the degradation of methyl orange was studied. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The phase composition (anatase/rutile ratio) and the photocatalytic activity of the final materials were found to be markedly influenced by the amount of the incorporated sulphur. On increasing the S-dopant amount, the anatase/rutile ratio and the photocatalytic activity of the as-prepared powders increased.     

WO_3/BiOBr复合催化剂的制备及可见光催化降解甲基橙

以Bi(NO_3)5·5H_2O、Na Br、H_2WO_4为原料,采用一步水热合成法合成不同n(W)∶n(Br)的WO_3/BiOBr复合催化剂,并通过SEM和TEM对催化剂进行表征分析。以甲基橙为探针污染物,考察前驱液pH、水热温度、水热时间和n(W)∶n(Br)对WO_3/BiOBr复合催化剂活性的影响。结果表明,在pH为10.2、100℃水热时间6 h合成n(W)∶n(Br)为0.02的WO_3/BiOBr复合催化剂活性最好,光照120 min后,对目标污染物的降解率达99.39%,较BiOBr催化剂(合成条件为原始pH值,100℃水热反应6 h)提高了30.85%。采用水热合成法制备的WO_3/BiOBr复合催化剂具有良好的可见光活性。