TiO2-PES Fibrous Composite Material for Ammonia Removal Using UV-A Photocatalyst

This study focused on the development and characterization of TiO2-PES composite fibers with varying TiO2 loading amounts using a phase inversion process. The resulting composite fibers exhibited a sponge-like structure with embedded TiO2 nanoparticles within a polymer matrix. Their photocatalytic performance for ammonia removal from aqueous solutions under UV-A light exposure was thoroughly investigated. The findings revealed that PeTi8 composite fibers displayed superior adsorption capacity compared to other samples. Moreover, the study explored the impact of pH, light intensity, and catalyst dosage on the photocatalytic degradation of ammonia. Adsorption equilibrium isotherms closely followed the Langmuir model, with the results indicating a correlation between qm values of 2.49 mg/g and the porous structure of the adsorbents. The research underscored the efficacy of TiO2 composite fibers in the photocatalytic removal of aqueous under UV-A light. Notably, increasing the distance between the photocatalyst and the light source resulted in de-creased hydroxyl radical concentration, influencing photocatalytic efficiency. These findings contribute to our understanding of TiO2 composite fibers as promising photocatalysts for ammonia removal in water treatment applications.

TiO_2/polyaniline composites:An efficient photocatalyst for the degradation of methylene blue under natural light

Polyaniline （PAn） sensitized nanocrystalline TiO2 composites （TiO2/PAn） were successfully prepared and used as an efficient photocatalyst for the degradation of dye methylene blue （MB）. The results showed that PAn was able to sensitize TiO2 efficiently and the composite photocatalyst could be activated by absorbing both the ultraviolet and visible light （λ： 190 ～ 800 nm）, whereas pure TiO2 absorbed ultraviolet light only （λ 〈 380 nm）. Under the irradiation of natural light, MB could be degraded more efficiently on the TiO2/PAn composites than on the TiO2 Furthermore, it could be easily separated from the solution by simple sedimentation.

Photocatalytic remediation ofγ-hexachlorocyclohexane contaminated soils using TiO_2 and montmorillonite composite photocatalyst

TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading γ-hexachlorocyclohexane （γ-HCH） in soils. After being spiked with γ-HCH, soil samples loaded with the composite photocatalysts were exposed to UV-light irradiation. The results indicated that the photocatalytic activities of the composite photocatalysts varied with the content of TiO2 in the order of 10%〈70%〈50% 〈30%, Moreover, the photocatalytic activity of the composite photocatalysts with TiO2 content 30% was higher than that of the pure P25 with the same mass of TiO2. The strong adsorption capacity of the composite photocatalysts and quantum size effect may contribute to its increased photocatalytic activities. In addition, effect of dosage of composite photocatalysts and soil pH on γ-HCH photodegradation was investigated. Pentachlorocyclohexene, trichlorocyclohexene, and dichlorobenzene were detected as photodegradation intermediates, which were gradually degraded with the photodegradation evolution.

First-principles study of the electronic and optical properties of the (Y,N)-codoped anatase TiO_2 photocatalyst

First-principles plane-wave pseudopotential calculations are performed to study the geometrical structures, for- mation energies, and electronic and optical properties of Y-doped, N-doped, and （Y, N）-codoped Ti02. The calculated results show that Y and N codoping leads to lattice distortion, easier separation of photogenerated electron-hole pairs and band gap narrowing. The optical absorption spectra indicate that an obvious red-shift occurs upon Y and N codoping, which enhances visible-light photocatalytic activity.

Fabrication of biomaterial/TiO2 composite photocatalysts for the selective removal of trace environmental pollutants

Trace environmental pollutants have become a serious problem with special attention on the hazardous heavy metals, refractory organics, and pathogenic microorganisms. With coupling biosorption and photocatalysis to develop biomaterial/TiO2 composite photocatalysts is a promising method to remove these trace pollutants because of the synergistic effect. Biomaterials provide multiple function groups which can selectively and efficiently enrich trace pollutants onto the surface of the photocatalysts, thus facilitating the following transformation mediated by TiO2 photocatalysis. Biomaterials can also help the dispersion and recovery of TiO2, or even modify the band structure of TiO2. The fabrication of chitosan/TiO2, cellulose/TiO2, as well as other biomaterial/TiO2 composite photocatalysts is discussed in detail in this review. The application significance of these composite photocatalysts for the selective removal of trace pollutants is also addressed. Several problems should be solved before the realistic applications can be achieved as discussed in the final section.

(N,F)-codoped TiO_2 Nanocrystals as Visible Light-activated Photocatalyst

（N, F）-codoped anatase TiO2 nanocrystals with active visible light response were prepared by using a simple sol-gel approach. X-ray photoelectron spectroscopy measurements suggested that the substitutional N and F species replaced the lattice oxygen atoms in TiO2 nanocrystals. Such nanocrystals showed strong absorption from 400 to 550 nm, which was mainly induced by nitrogen doping. The phase transformation from anatase to rutile was hindered by fluorine doping at high calcination temperatures, which was verified by XRD patterns. The N2 adsorption-desorption isotherms revealed the absence of mesopores in these nanocrystals. The （N, F）- codoped TiO2 nanocrystals showed satisfying photocatalytic activity on the photo-degradation of methylene blue under visible light.

A Novel High Active TiO_2/AC Composite Photocatalyst Prepared by Acid Catalyzed Hydrothermal Method

A high active novel TiO2/AC composite photocatalyst was prepared and used for phenol degradation. It was much more active than P-25 and exhibiting good decantability, less deactivation after several runs and less sensitive to pH change. Diffuse reflectance spectra （DRS） revealed that the electronic change in TiO2 did not occur by the addition of AC. Results of SEM and XRD suggested that better TiO2 distribution can be achieved when optimal AC content was adopted. The performance of the prepared TiO2/5AC catalyst revealed great practical potential in wastewater treatment field.

Photocatalytic Degradation of Ethylene Dichloride in Water Using Nano TiO₂Supported on Clinoptilolite as a Photocatalyst

In this article one of the advanced oxidation processes (AOP) combined methods, photocatalyst /H2O2, is utilized in order to study photodegradation of ethylene dichloride (EDC) in water. Nano Titanium (IV) Oxide, supported on Clinoptilolite (CP) (Iranian natural zeolite) using solid-state dispersion (SSD) method for improvement of its photocatalytic properties. The results show that the TiO2/Clinoptilolite (SSD) is an active photocatalyst. The effects of five important photocatalytic reaction parameters including the initial concentration of ethylene dichloride, the ratio of TiO2/Clinoptilolite, the catalyst concentration, H2O2 concentration and pH in photodegradation of ethylene dichloride were examined. In this experiments, the design and also the optimum parameters were obtained by Taguchi Method, using Design Expert8®software. Taguchi's L27 (5^3) orthogonal array design was employed for the experimental plan. Four parameters were found to be significant whereas, pH was found to be an insignificant parameter after conducting experiments. A first order reaction with K = 0.007 min-1 was observed for the photocatalytic degradation reaction.

Fe/C Modified TiO_2 Photocatalyst and Photodegradation of 4-t-octylphenol

[Objective]The research aimed to study synthesis of the TiO2 photocatalyst modified by Fe/C and photodegradation of 4-t-octylphenol.[Method]Fe/C modified TiO2 photocatalyst was made by sol-gel and solvothermal synthesis methods.4-t-octylphenol as test object,photocatalytic performance of the catalyst was investigated.Influences of the Fe doping amount,catalyst amount,pH and sun-light irradiation on reaction were discussed.Moreover,catalyst performance under the condition of interfering ion existence was studied.[Result]When Fe/C doping amount was 0.6%,under the reaction condition of 25 ℃,pH =9.0,300 W mercury lamp and 1.0 g/L of catalyst amount,4-t-octylphenol concentration decreased from 1.00 to 0.02 mg/L by degradation for 100 min.Rises of pH and light intensity could improve catalyst efficiency.The existences of Na ＋,K ＋ and Ca2＋ had no effect on degradation activity of the catalyst.[Conclusion]Fe/C modified TiO2 photocatalyst had better degradation effect on environmental hormone in the sewage.

载银光催化剂Ag-TiO_2合成及光催化性能

通过光化学沉积法合成了负载有贵金属银的高活性光催化剂Ag -TiO2 ,通过以亚甲基蓝为模型化合物对所制得的光催化剂的光催化活性进行评价 ,研究了制备过程中的主要因素对催化剂活性的影响。结果表明 ,当AgNO3的含量为 0 .1mol/L时 ,AgNO3 溶液用量为 7mL/gTiO2 ,AgNO3 与Na2 NO3 的溶液体积比为 2∶1,所合成的Ag -TiO2 光催化剂活性最高。在相同条件下 ,Ag -TiO2 对亚甲基蓝的降解速率是原料TiO2 的 8倍。

掺杂过渡金属离子的TiO_2复合纳米粒子光催化剂──罗丹明B的光催化降解

The transition metal ion doped TiO 2 nanoparticles were prepared with hydrothermal method, and the effects of doping different metal ions on the ability of TiO 2 in photocatalyzing degradation of rhodamine B(RB) were studied. The results showed that the doping of Fe 3+ , Co 2+ , Ni 2+ and Cr 3+ in TiO 2 nanoparticles made the photocatalytic efficiency of the TiO 2 particles reduce and the higher the initial content of Fe 3+ , the lower the ability of TiO 2 in photocatalyzing the degradation of RB. But the doping of Zn 2+ and Cd 2+ , especially Zn 2+ , made the photocatalytic efficiency of the TiO 2 particles enhance, showing a great increase of the rate constant( k ) and the initial reaction rate( r ini ).

单分散纳米TiO_2光催化剂的水解-溶胶制备法

以Ti(SO4 ) 2 为原料 ,在一定温度下直接水解、胶溶、加入晶种、熟化 ,制备出单分散性、热稳定性良好、平均粒径在 2 2nm左右、比表面积在 80m2 /g以上的TiO2 纳米微粒。研究了Ti(SO4 ) 2 浓度、水解时间及晶种对纳米微粒粒径的影响。对样品进行了TG DTA ,XRD和SEM分析。结果表明 :样品经真空冷冻干燥后 ,TiO2 粉体主要为锐钛矿型 ,且随焙烧时间增加和温度升高 ,其金红石型含量显著增多 ,粉体粒径也有一定增大 ,但在不同的温度区间粒径增长速率有较大的区别。

反胶束体系制备负载型TiO_2纳米光催化剂

在 AOT/异辛烷反胶束体系中制备了粒径为 2～ 5 nm的单分散球形 Ti O2 纳米粒子 ,用 TEM,DSC和 XRD等手段对其进行了分析 ;用浸渍法以小孔分子筛 HZSM-5为载体制备了负载型 Ti O2 纳米粒子 ,用FTIR,Langmuir及 BET等手段进行了表征 ;用以上 2种 Ti O2 粒子作光催化剂进行了简单模拟废水处理研究 ,用 UV-Vis光谱分析其催化效果表明 ,负载型 Ti O2 纳米粒子比纯 Ti O2 纳米粒子的光催化活性更高 .

纳米TiO_2对光催化降解SDBS的影响

本文以沉淀法制备得到了纳米 Ti O2 光催化剂 ,考察了原料、沉淀剂、沉淀 p H值、催化剂焙烧温度和焙烧时间等对催化剂粒子尺寸、晶相含量和光催化活性的影响。优化工艺条件下制备得到的催化剂原级粒子尺寸为 8.5 nm。以该催化剂在 5 0 0 W紫外线高压汞灯照射下光催化氧化十二烷基苯磺酸钠 (SDBS) 5小时 ,化学需氧量 (COD)去除率达到 91 %以上。

纳米SnO2@TiO2包覆催化剂的制备及表征

采用活性层包覆法在自制超细SnO2胶体粒子表面包覆TiO2, 制备出SnO2@TiO2包覆型复合催化剂, 以其对有机磷农药DDVP的降解效果作为评价光催化活性的标准, 对制备条件进行了优化, 并用XRD、 TEM和BET等手段对样品进行了表征. 结果表明, SnO2胶体乙醇溶液含水量20％, 钛酸丁酯质量分数为34.5％, 灼烧温度680 ℃时制得TiO2含量56.45%的包覆样品SnO2@TiO2为纳米级粒子,且其光催化活性最佳.

TiO_2光催化氧化去除有机污染物的研究进展

本文综述了近年来TiO2 光催化降解有机污染物的研究进展 ,讨论了各类有机污染物光催化氧化反应的特点。

TiO_2/SiO_2/Fe_3O_4的制备及其光催化性能

用溶胶 凝胶法在表面包覆了SiO2 的磁基体Fe3 O4上负载TiO2 ,从而得到了易于磁性固液分离的光催化剂TiO2 /SiO2 /Fe3 O4,并通过XPS、XRD、TEM、IR和UV Vis等测试对样品进行了表征。研究了磁载光催化剂TiO2 /SiO2 /Fe3 O4在太阳光和紫外光下 ,对染料Orange Ⅱ的脱色作用。结果表明 ,在Fe3 O4和TiO2 之间包覆一层无定型SiO2 ,可使催化剂的脱色率由 73 1%提高到 99 8%。

水热法制备高活性TiO_2光催化剂的研究进展

简述了TiO2 作为光催化剂应有的性质 ;着重介绍了高活性和超高活性TiO2 光催化剂纳米粉体和薄膜的水热法制备研究情况 ;指出了该法尚须解决的问题及今后努力的方向。

TiO_2膜光催化剂的改进及表征

提出用粉末—溶胶法制备TiO2 薄膜型光催化剂 ,介绍了粉溶法的制备工艺及改变 pH值对催化活性的影响。研究结果表明 ,利用粉溶法或添加浓HNO3后制备的TiO2 薄膜光催化剂表现出了较高的光催化活性。结合结构表征详细分析了其中的原因。认为粉溶法制备的催化剂表面更粗糙 ,比表面积增大 ,膜厚度减小 ,这些都可能是其催化活性提高的原因。而加酸后膜催化活性提高主要是因为酸性条件下表面几乎没有Ti3+表面态 ,利于光生电子与光生空穴的分离。

粉末状和薄膜状TiO_2对敌敌畏的光催化降解

TiO 2 powder, TiO 2/SiO 2 coated particle, and thin film reactor were prepared by sol gel process. Their morphology and structure were characterized by SEM, XRD and IR. Their effects of photocatalytic degradation for dichlorvos were studied. The Photocatalytic reactivity of thin film TiO 2 are better than that of powder TiO 2.