scholarly journals An Overview: Recent Development of Titanium Oxide Nanotubes as Photocatalyst for Dye Degradation

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Chin Wei Lai ◽  
Joon Ching Juan ◽  
Weon Bae Ko ◽  
Sharifah Bee Abd Hamid

Today, organic dyes are one of the largest groups of pollutants release into environment especially from textile industry. It is highly toxic and hazardous to the living organism; thus, the removal of these dyes prior to discharge into the environment is essential. Varieties of techniques have been employed to degrade organic dyes and heterogeneous photocatalysis involving titanium dioxide (TiO2) appears to be the most promising technology. In recent years, TiO2nanotubes have attracted much attention due to their high surface area and extraordinary characteristics. This paper presents a critical review of recent achievements in the modification of TiO2nanotubes for dye degradation. The photocatalytic activity on dye degradation can be further enhanced by doping with cationic or anionic dopant.

2014 ◽  
Vol 911 ◽  
pp. 126-130 ◽  
Author(s):  
Mohd Hasmizam Razali ◽  
M.N. Ahmad-Fauzi ◽  
Abdul Rahman Mohamed ◽  
Srimala Sreekantan

Copper doped titanium dioxide (Cu-TiO2) nanotubes were synthesised by hydrothermal method. The samples were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and nitrogen gas adsorption. The photocatalytic activity of the copper doped titanium dioxide nanotubes was investigated by photodegradation of methyl orange under UV light. The structural and morphological studies showed that, the copper was incorporated into interstitial positions of the TiO2lattice to form a new phase of TiO2(hexagonal). The copper doped TiO2nanotubes possessed high surface area and pore volume, results high photocatalytic activity for degradation of methyl orange (MO).


Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 293
Author(s):  
Xinghui Zhang ◽  
Zhibin Geng ◽  
Juan Jian ◽  
Yiqiang He ◽  
Zipeng Lv ◽  
...  

In this work, hexagon-shaped potassium ferrite (K2Fe4O7) crystals with different sizes were prepared using the hydrothermal method. The crystals showed a narrow band gap of 1.44 eV, revealed by UV-visible diffuse reflectance spectroscopy, and was thus used as a heterogeneous Fenton catalyst to degrade methylene blue (MB) and crystal violet (CV) in the presence of green oxidant H2O2 under visible-light irradiation. Among the investigated crystals, the as-prepared one with an average size of 20 µm (KFO-20) exhibited better photocatalytic activity due to its high surface area. When it was used as a photo-Fenton catalyst, 100% MB and 92% CV were degraded within 35 min. Moreover, the catalyst maintained high photocatalytic activity and was stable after four continuous cycles. The trapping experiments showed that the active hydroxyl radical (·OH) was dominant in the photo-Fenton reaction. Therefore, this new photo-Fenton catalyst has great potential for the photocatalytic degradation of dye contaminants in water.


Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2823
Author(s):  
Stephen Abela ◽  
Clayton Farrugia ◽  
Ryan Xuereb ◽  
Frederick Lia ◽  
Edwin Zammit ◽  
...  

Anodic titanium dioxide (TiO2) nanotubes were found to be active photocatalysts. These photocatalysts possess a high surface area, even when supported, rendering them potential candidates for water treatment. In this work, photocatalytic surfaces were produced by anodizing commercially pure Ti plates using two different electrolyte compositions and correspondingly diverse process parameters. Changes in the physical and chemical stability as well as photocatalytic activity were studied over a fifty-two-week aging process. During this period, the nanotubular surfaces were exposed to flowing synthetic greywater, solar irradiation, and the natural environment. The physical and phase stability of the materials anodized using the organic electrolyte were found to be outstanding and no degradation or change in crystalline structure was observed. On the other hand, materials anodized in the aqueous electrolyte proved to suffer from light-induced phase transition from anatase to rutile. Surfaces synthesized in the organic electrolyte were more resistant to fouling and showed a better tendency to recover photocatalytic activity upon cleaning. In conclusion, the nanotubes produced in the organic electrolyte proved to be stable, rendering them potentially suitable for real-life applications.


Author(s):  
Teera Butburee ◽  
Yang Bai ◽  
Lianzhou Wang

Branched nanostructures represent a unique group of nanoarchitectures exhibiting advantageous high surface area and excellent charge transport for energy conversion application compared to their bulk counterparts. Especially, branched titanium dioxide...


Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.


Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215
Author(s):  
Ewa Wierzbicka ◽  
Karolina Syrek ◽  
Klaudia Mączka ◽  
Grzegorz D. Sulka

High surface area, self-organized nanoporous ZrO2 arrays with perfect adhesion to the Zr substrate were synthesized by anodization in an aqueous electrolyte containing (NH4)2SO4 and NH4F. The obtained semiconductor materials were tested as photocatalysts for decolorization of the methyl red (MR) as a model azo dye pollutant. It was demonstrated that as-synthesized anodic ZrO2 anodic layers are already crystalline and, therefore, do not require further thermal treatment to provide a high photocatalytic performance. However, photocatalytic efficiency could be improved by annealing at a relatively low-temperature of 350 °C. Higher annealing temperatures caused a gradual drop of photocatalytic activity. The photocatalytic behavior was correlated with the crystal phase transformation in anodic ZrO2. It was found that higher photocatalytic activity was observed for the tetragonal phase over the monoclinic phase (predominant at elevated temperatures). It results from the optimal and complex electronic structure of annealed ZrO2 with three different energy states having absorption edges at 2.0, 4.01 and 5.28 eV.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Garima Rathee ◽  
Amardeep Awasthi ◽  
Damini Sood ◽  
Ravi Tomar ◽  
Vartika Tomar ◽  
...  

Abstract It would be of great significance to introduce a new biocompatible Layered Double Hydroxide (LDH) for the efficient remediation of wastewater. Herein, we designed a facile, biocompatible and environmental friendly layered double hydroxide (LDH) of NiFeTi for the very first time by the hydrothermal route. The materialization of NiFeTi LDH was confirmed by FTIR, XRD and Raman studies. BET results revealed the high surface area (106 m2/g) and the morphological studies (FESEM and TEM) portrayed the sheets-like structure of NiFeTi nanoparticles. The material so obtained was employed as an efficient adsorbent for the removal of organic dyes from synthetic waste water. The dye removal study showed >96% efficiency for the removal of methyl orange, congo red, methyl blue and orange G, which revealed the superiority of material for decontamination of waste water. The maximum removal (90%) of dyes was attained within 2 min of initiation of the adsorption process which supported the ultrafast removal efficiency. This ultrafast removal efficiency was attributed to high surface area and large concentration of -OH and CO32− groups present in NiFeTi LDH. In addition, the reusability was also performed up to three cycles with 96, 90 and 88% efficiency for methyl orange. Furthermore, the biocompatibility test on MHS cell lines were also carried which revealed the non-toxic nature of NiFeTi LDH at lower concentration (100% cell viability at 15.6 μg/ml). Overall, we offer a facile surfactant free method for the synthesis of NiFeTi LDH which is efficient for decontamination of anionic dyes from water and also non-toxic.


2021 ◽  
Vol 11 (1) ◽  
pp. 67-73
Author(s):  
Manh Nguyen Ba ◽  
Trang Pham Thi Thu ◽  
Hoa Tran Thi ◽  
Giang Le Ha

Nanocomposite Zn-BTC/GO (BTC: benzene-1,3,5-tricarboxylic, GO: graphene oxide) was successfully synthesized by hydrothermal treatment with a microwave method. Samples were characterized by XRD, FTIR, EDS-mapping, BET, SEM, UV-vis DRS and XPS. SEM-image result showed nano Zn-BTC/GO particles size of 50-80 nm. Nanocomposite Zn-BTC/GO showed the a high surface area (1303 m2/g) and pore volume (1.08 cm3/g). The Zn-BTC/GO nanocomposite were tested for the photocatalytic degradation of reactive dye (Reactive Red 195) in an aqueous solution. The Zn-BTC/GO composites exhibited high photocatalytic activity. Thus, at the pH of 6.5 and the high initial concentration of 30 mg RR-195/L, removal efficiency reached the value of 96.16% after 60 min reaction. Moreover, nano Zn-BTC also showed high RR-195 removal efficiency after 3 catalytic regeneration. This contributes to sustainable development and green chemistry.


2019 ◽  
Vol 74 (3) ◽  
pp. 259-263 ◽  
Author(s):  
M. Shamshi Hassan

AbstractHierarchical bismuth vanadate (BiVO4) nano-knitted hollow cages have been synthesized by simple hydrothermal method and characterized by scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray spectrometer, Fourier transform infrared, UV-Vis, and Raman. The photodegradation efficiency of BiVO4 nanocage for universally used methylene blue dye. The BiVO4 hollow nanostructure demonstrated better photocatalytic competence in dye degradation as compared to the commercial TiO2 powders (P25). The excellent dye degradation can be certified to the high crystallisation of monoclinic BiVO4 and hollow nanostructure, which leads to high surface area and small bandgap energy of 2.44 eV.


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