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Investigation of photocatalytic degradation of phenol by Fe(III)-doped TiO2 and TiO2 nanoparticles.

Hemmati Borji S, Nasseri S, Mahvi AH, Nabizadeh R, Javadi AH - J Environ Health Sci Eng (2014)

Bottom Line: In addition, the effects of various operational parameters on photocatalytic degradation, such as pH, initial concentration of phenol and amount of photocatalyst were examined and optimized.At all different initial concentration, highest degradation efficiency occurred at pH = 3 and 0.5 g/L Fe(III)-doped TiO2 dosage.With increase in initial concentration of phenol, photocatalytic degradation efficiency decreased.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Environmental Health Engineering, School of Public Health and Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.

ABSTRACT
In this study Fe (III)-doped TiO2 nanoparticles were synthesized by sol-gel method at two atomic ratio of Fe/Ti, 0.006 and 0.034 percent. Then the photoactivity of them was investigated on degradation of phenol under UV (<380 nm) irradiation and visible light (>380 nm). Results showed that at appropriate atomic ratio of Fe to Ti (% 0.034) photoactivity of Fe(III)-doped TiO2 nanoparticles increased. In addition, the effects of various operational parameters on photocatalytic degradation, such as pH, initial concentration of phenol and amount of photocatalyst were examined and optimized. At all different initial concentration, highest degradation efficiency occurred at pH = 3 and 0.5 g/L Fe(III)-doped TiO2 dosage. With increase in initial concentration of phenol, photocatalytic degradation efficiency decreased. Photoactivity of Fe (III)-doped TiO2 under UV irradiation and visible light at optimal condition (pH = 3 and catalyst dosage = and 0.5 g/L) was compared with P25 TiO2 nanoparticles. Results showed that photoactivity of Fe(III)-doped TiO2 under visible light was more than P25 TiO2 photoactivity, but it was less than P25 TiO2 photoactivity under UV irradiation. Also efficiency of UV irradiation alone and amount of phenol adsorption on Fe(III)-doped TiO2 at dark condition was investigated.

No MeSH data available.


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Effect of pH on photocatalytic degradation of phenol; C0 = 100 mg/L and Fe(III)-doped TiO2 = 0.5 g/L.
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Figure 6: Effect of pH on photocatalytic degradation of phenol; C0 = 100 mg/L and Fe(III)-doped TiO2 = 0.5 g/L.

Mentions: Figure 6. illustrates the effect of pH on phenol degradation (C/C0, where C0 is the initial phenol concentration and C is the phenol concentration at time t). The highest degradation efficiency occurred at pH = 3 and the lowest degradation occurred at pH = 7. This is attributed to the fact that, condition in addition to OH radicals produced by Fe(III)-doped TiO2/UV process, there are more hydrogen ions at acidic condition and these ions can cause the production of more OH radicals (as a major agent of degradation at photocatalytic reactions) to degrade phenol. This conclusion is similar to the report of Guo et al. [21], which indicated that the H+ ions have important role on OH radicals formation. But higher phenol degradation at pH = 11 in comparison with neutral pH is due to the presence of phenol molecules as negatively charged phenolate species. These anions are more reactive than phenol molecules. Also in alkaline conditions there is an increase in the concentration of OH radicals [22]. Although this increase can be cause of more degradation of phenol at alkaline pH in comparison with neutral pH, but when the concentration of OH− is higher in the solution, it prevents the penetration of UV light to reach the catalyst surface. Moreover, high pH favors the formation of carbonate ions which are effective scavengers of OH− ions and can reduce the degradation rate [17,23]. These can be cause of the less degradation of phenol at alkaline pH in comparison with acidic pH.


Investigation of photocatalytic degradation of phenol by Fe(III)-doped TiO2 and TiO2 nanoparticles.

Hemmati Borji S, Nasseri S, Mahvi AH, Nabizadeh R, Javadi AH - J Environ Health Sci Eng (2014)

Effect of pH on photocatalytic degradation of phenol; C0 = 100 mg/L and Fe(III)-doped TiO2 = 0.5 g/L.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4125378&req=5

Figure 6: Effect of pH on photocatalytic degradation of phenol; C0 = 100 mg/L and Fe(III)-doped TiO2 = 0.5 g/L.
Mentions: Figure 6. illustrates the effect of pH on phenol degradation (C/C0, where C0 is the initial phenol concentration and C is the phenol concentration at time t). The highest degradation efficiency occurred at pH = 3 and the lowest degradation occurred at pH = 7. This is attributed to the fact that, condition in addition to OH radicals produced by Fe(III)-doped TiO2/UV process, there are more hydrogen ions at acidic condition and these ions can cause the production of more OH radicals (as a major agent of degradation at photocatalytic reactions) to degrade phenol. This conclusion is similar to the report of Guo et al. [21], which indicated that the H+ ions have important role on OH radicals formation. But higher phenol degradation at pH = 11 in comparison with neutral pH is due to the presence of phenol molecules as negatively charged phenolate species. These anions are more reactive than phenol molecules. Also in alkaline conditions there is an increase in the concentration of OH radicals [22]. Although this increase can be cause of more degradation of phenol at alkaline pH in comparison with neutral pH, but when the concentration of OH− is higher in the solution, it prevents the penetration of UV light to reach the catalyst surface. Moreover, high pH favors the formation of carbonate ions which are effective scavengers of OH− ions and can reduce the degradation rate [17,23]. These can be cause of the less degradation of phenol at alkaline pH in comparison with acidic pH.

Bottom Line: In addition, the effects of various operational parameters on photocatalytic degradation, such as pH, initial concentration of phenol and amount of photocatalyst were examined and optimized.At all different initial concentration, highest degradation efficiency occurred at pH = 3 and 0.5 g/L Fe(III)-doped TiO2 dosage.With increase in initial concentration of phenol, photocatalytic degradation efficiency decreased.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Environmental Health Engineering, School of Public Health and Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.

ABSTRACT
In this study Fe (III)-doped TiO2 nanoparticles were synthesized by sol-gel method at two atomic ratio of Fe/Ti, 0.006 and 0.034 percent. Then the photoactivity of them was investigated on degradation of phenol under UV (<380 nm) irradiation and visible light (>380 nm). Results showed that at appropriate atomic ratio of Fe to Ti (% 0.034) photoactivity of Fe(III)-doped TiO2 nanoparticles increased. In addition, the effects of various operational parameters on photocatalytic degradation, such as pH, initial concentration of phenol and amount of photocatalyst were examined and optimized. At all different initial concentration, highest degradation efficiency occurred at pH = 3 and 0.5 g/L Fe(III)-doped TiO2 dosage. With increase in initial concentration of phenol, photocatalytic degradation efficiency decreased. Photoactivity of Fe (III)-doped TiO2 under UV irradiation and visible light at optimal condition (pH = 3 and catalyst dosage = and 0.5 g/L) was compared with P25 TiO2 nanoparticles. Results showed that photoactivity of Fe(III)-doped TiO2 under visible light was more than P25 TiO2 photoactivity, but it was less than P25 TiO2 photoactivity under UV irradiation. Also efficiency of UV irradiation alone and amount of phenol adsorption on Fe(III)-doped TiO2 at dark condition was investigated.

No MeSH data available.


Related in: MedlinePlus