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.

可见光响应氮杂化TiO_2-N薄膜对水源水体的杀菌作用

以尿素为氮源,采用Sol-gel法及浸渍-提拉法制备氮杂化TiO2-N薄膜,并运用正交试验法优化TiO2-N薄膜的最佳制备条件;利用AFM分析技术对TiO2-N薄膜表面形貌进行表征;在太阳光光催化反应器中,探讨TiO2-N薄膜对饮用水供水水源水体中大肠菌群的杀菌作用。结果表明,热处理条件是影响TiO2-N薄膜制备的关键因素,各个影响因素的主次顺序为热处理温度>停留温度>热处理时间,在最佳条件下制备的TiO2-N薄膜,在太阳光作用下光解30min时,对饮用水供水水源水体中大肠菌群的杀菌率达到57.7%以上;Ag的协同掺杂(Ag-TiO2-N)或在TiO2-N薄膜表面的沉积(Ag/TiO2-N),显著提高了TiO2-N薄膜的杀菌作用,对大肠菌群的杀菌率可达90%以上。

p-n异质结TiO_2/NiO光催化剂的制备及其性能研究

采用溶胶凝胶和浸渍煅烧相结合的方法,制备出了具有p-n异质结结构的球形二氧化钛表面负载氧化镍颗粒的复合光催化剂.利用XRD、TEM、UV-Vis和PL等方法对催化剂的晶相组成、微观结构、吸光性能和光致发光性能等进行了表征.结果表明氧化镍晶粒与二氧化钛晶粒紧密接触形成p-n异质结.氧化镍颗粒的负载使复合光催化剂的吸收带边发生了明显的红移,并进入了可见光区.形成的p-n异质结促进了二氧化钛光生电子和空穴的分离,从而降低了其本征发光光强度.通过在可见光条件下对亚甲基蓝的降解研究了其光催化性能,结果表明,氧化镍颗粒的负载使二氧化钛的光催化效果在可见光区有了显著地提高,并在一定范围内随着氧化镍含量的增加光催化效果也随之提高.

球磨法制备p-n结型光催化剂NiO/TiO_2

本文采用n-TiO2粉末与p-NiO粉末按一定比例经球磨形成p-n结型NiO/TiO2光催化剂。研究了NiO的掺杂比及球磨时间对光催化活性的影响,并探讨了p-n结型NiO/TiO2光催化剂的催化机理。实验结果表明:球磨法制备的p-n结型NiO/TiO2光催化剂比纯TiO2粉末的催化活性均有所降低。在0-48小时内,当球磨时间为12h时,掺杂比为1‰的p-n结型NiO/TiO2光催化剂的活性最大,在紫外光降解20min时,其对Cr6+的降解率为20.63%,对NO-2的降解率为29.06%。

A review on TiO_2-based Z-scheme photocatalysts

TiO2‐based Z‐scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency.In this review,the reaction mechanism of Z‐scheme photocatalysts,recent research progress in the application of TiO2‐based Z‐scheme photocatalysts,and improved methods for photocatalytic performance enhancement are explored.Their applications,including water splitting,CO2reduction,decomposition of volatile organic compounds,and degradation of organic pollutants,are also described.The main factors affecting the photocatalytic performance of TiO2‐based Z‐scheme photocatalysts,such as pH,conductive medium,cocatalyst,architecture,and mass ratio,are discussed.Concluding remarks are presented,and some suggestions for the future development of TiO2‐based Z‐scheme photocatalysts are highlighted.

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.

(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.

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.

Spectra analysis and O_2 evolution for TiO_2 photocatalyst compounded with indirect transition semiconductors

The photo absorbing, photo transmitting and photoluminescence performances of WiO2 photocatalysts compounded with V2O5 or WO3 were investigated by UV-Vis spectra, transmitting spectra, and PL spectra, respectively. The energy band structures of TiO2 photocatalysts were analyzed. The photocatalytic activities of the TiO2 photocatalysts were investigated by splitting of water for 02 evolution. The results indicate that the band gaps of WO3 and V205 are about 2.8 and 2.14 eV, respectively, and the band gap of rutile TiO2 is about 3.08 eV. Speeds of water splitting for 2%WO3-TiO2 and 8%V2O5-TiO2 photocatalysts are 420 and 110 μmol/（L.h）, respectively, under UV light irradiation. V2O5 and WO3 compounded with suitable concentration can improve the photocatalytic activity of TiO2 with Fe3＋ as electron acceptor.

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 kinetics in Rhodamine B dye degradation with poriferous TiO_2 photocatalyst

A type of poriferous TiO2 material was prepared using cetyl trimethyl ammonium bromide as a template agent and butyl tetra titanate as a precursor. Through studying the photocatalytic kinetic activity of Rhodamine B photocatalytic degradation reaction with a UV-1601PC ultraviolet-visible spectrophotometer, the photocatalytic degradation process of Rhodamine B was found to not correspond to the first-order kinetic process completely. According to the reaction phenomenon, the photocatalytic degradation process of Rhodamine B with poriferous TiO2 involved two irreversible reactions. The kinetic model was tested using experimental data.

Preparation and photocatalysis properties of composite photocatalyst CoPcS/TiO2/K2Ti4O9

Photocatalyst CoPcS/TiO2 was prepared by sol-gel method. Composite CoPcS/TiO2/K2Ti4O9 was prepared by dipping. It was incandesced at various temperatures and modification effect was compared. The results showed that optical absorption of sample incandesce at 423K occurred significant red-shift. Light absorption width extended from ultraviolet region to visible region, especially there was an intensive absorption between 600 nm and 680 nm. X-ray diffraction spectrogram showed that TiO2 in sample still maintained anatase crystal form. Under the illumination of visible light, photocatalysis degradation experiment was taken with Eosin B as simulated pollutants. Decoloration rate of Eosin B was much improved. The rate can reach 80% in 300 minutes.

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 .