Improvement in TiO2 photocatalytic performance by ZrO2 nanocompositing and immobilizing

2019

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Water contamination along with the environmental issues resulted by industrial wastewaters have caused a trend in applying semiconducting photocatalysts, among which TiO 2 composites have been particularly focused on to overcome the drawbacks of titanium(IV) oxide also known as titania. In the current investigation, waste chips of a structural steel bar with the chemical composition of Fe 2 O 3 were utilised to obtain the TiO 2-Fe 2 O 3 composite. X-ray diffraction (XRD), field-emission scanning electron microscopy, energy dispersive spectroscopy, diffusive reflectance spectra, and Brunauer-Emmett-Teller analyses were made to evaluate the composition and structure of the samples. Furthermore, the photocatalytic performance of the samples was studied by methyl orange (MeO) degradation. XRD spectra proved the presence of anatase and Fe 2 O 3 phases in the sample of 10%wt. Fe 2 O 3. The results indicate that as the Fe 2 O 3 content rises, the bandgap narrows. However, the specific surface area enlarges as this amount goes up to a certain limit (10%wt.), from which any further increase leads to a reduction in the specific surface area. The obtained results of MeO decolourisation presented the Fe 2 O 3 of 10%wt. and bandgap of 2.72 eV, and the specific surface area of 63 m 2 /g to be of the highest efficiency (96%).

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Synthesis and characterisation of TiO ₂ nanoparticles/Fe ₂ O ₃ waste chips composite

2019

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“…These include generating electron-hole pairs by photonic-excitation of a photocatalyst (i.e. semiconductor) using UV photons [3,8]. TiO 2 has proved to be a promising semiconductor among others for its physical/chemical properties, low cost, chemical stability, and non-toxicity [1,[7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic removal of cyanide and Cr(IV) from wastewater in the presence of each other by using TiO ₂ /UV

2019

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Cyanide (CN) and chromium (VI) are hazardous, toxic pollutants whose presence in water and wastewater can seriously affect human and its environment, hence the necessity of controlling these contaminants. In this work, by using TiO 2 /UV, the simultaneous photocatalytic reduction of Cr(VI) and oxidation of CN in aqueous suspensions were investigated. Variations of this study were pH, pollutant concentration, and reaction time. CN and total chromium were determined by Titrimetric method, and Colourimetric method, respectively. Maximum removal of chromium and CN occurs at pH 2.3 and 10, respectively. In the binary system, the electron-hole recombination is blocked and as a result, total efficiency increases. An increase in the initial concentrations of CN and Cr(VI) led to a rise in the reduction efficiency of Cr(VI) and CN up to an optimum amount, and then it went into decline as the concentration of the pollutants increased any further. The maximum quantum efficiency of Cr(VI) photoreduction with CN being present was calculated to be 23% at room temperature. Furthermore, the kinetic experimental was investigated and it became evident that the pseudo-first-order kinetic model is capable of defining Cr(VI) and CN both. Finally, based on the obtained results, a TiO 2 system is proposed to remove both pollutants.

“…In the last three decades, new methods such as oxidation, and adsorbing the pollutants by zeolite and photocatalysts have been focused on owing to their low initial cost, the simplicity of design, ease of operation, and the possibility of reusing the resulted water [6, 7].…”

Section: Introductionmentioning

confidence: 99%

“…There has been an increasing tendency to use semiconducting photocatalysts recently [6, 11]. Photocatalysts are fundamentally based on electron–hole pair production in the semiconductor through adsorbing light whose bandgap is higher than or equal to that of the semiconductor [1, 13].…”

Section: Introductionmentioning

confidence: 99%

Investigation of photocatalytic performance of natural zeolite/TiO ₂ composites

Hassanabadi

Mansouri

et al. 2019

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The growing increase of industrial wastewater, environmental contaminations, and the necessity of clean water has stressed the importance of removing pollutants. One of the effective means of removing pollutants from water and wastewater is by utilising zeolite. Zeolite, despite possessing unique photophysical properties (such as numerous fine cavities, the high capability to adsorb, and chemical-thermal stability), represents some limitations when being used. Depositing photocatalysts on zeolite particles to improve its removal potential is of much interest. In this work, therefore, TiO 2 nanoparticles were deposited on fine particles of zeolite. Zeolite/TiO 2 composites were evaluated by X-ray diffractometer, scanning electron microscope, Brunauer-Emmett-Teller, diffuse reflectance spectroscopy analyses. The results indicate that the presence of TiO 2 nanoparticles reduces the specific surface area. However, it causes the ability to absorb UV light. Increasing the amount of TiO 2 any further will bring about a redshift in absorption edge. Photocatalytic properties of the composites were assessed by methyl orange and cyanide ion removal examination. The 10%TiO 2 composite with the specific surface area of 34 m 2 /g and bandgap energy of 3.3 eV showed to be the most efficient. The superior photocatalytic performance of 10%TiO 2 sample was confirmed by the examination of producing hydrogen from water/methanol.