Comparative study of the structural, optical and photocatalytic properties of semiconductor metal oxides toward degradation of methylene blue

Talebian, Nasrin; Nilforoushan, Mohammad Reza

doi:10.1016/j.tsf.2009.07.135

Cited by 107 publications

(52 citation statements)

References 24 publications

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“…The optimum calcinations temperature was shown to be 400°C when S-TiO 2 was the visible light catalyst (Tian et al 2009). Talebian and Nilforoushan (2009) studied the effect of annealing temperature (250-550°C) on the photocatalytic activity of In 2 O 3 film for the degradation of MB. The optimum annealing temperature was 550°C, and the activity of In 2 O 3 film was directly related to degree of crystallinity at higher temperature.…”

Section: Film Fabrication Technique and Calcination Temperaturementioning

confidence: 99%

Advances in Heterogeneous Photocatalytic Degradation of Phenols and Dyes in Wastewater: A Review

Ahmed

Rasul

Martens

et al. 2010

Water Air Soil Pollut

368

138

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The heterogeneous photocatalytic water purification process has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible light spectrum. This paper aims to review and summarize the recently published works in the field of photocatalytic oxidation of toxic organic compounds such as phenols and dyes, predominant in wastewater effluent. In this review, the effects of various operating parameters on the photocatalytic degradation of phenols and dyes are presented. Recent findings suggested that different parameters, such as type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/ electron acceptors, mode of catalyst application, and calcinations temperature can play an important role on the photocatalytic degradation of organic compounds in water environment. Extensive research has focused on the enhancement of photocatalysis by modification of TiO 2 employing metal, non-metal, and ion doping. Recent advances in TiO 2 photocatalysis for the degradation of various phenols and dyes are also highlighted in this review.

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Section: Film Fabrication Technique and Calcination Temperaturementioning

confidence: 99%

Advances in Heterogeneous Photocatalytic Degradation of Phenols and Dyes in Wastewater: A Review

Ahmed

Rasul

Martens

et al. 2010

Water Air Soil Pollut

368

138

View full text Add to dashboard Cite

show abstract

“…The mechanism of methylene blue photo-oxidation in aqueous solutions containing TiO 2 is complex, and has yet to be fully resolved. However, there is general consensus the overall mechanism is driven by hydroxyl radicals generated on the surface of TiO 2 , as summarised below [13][14][15][16][17][18][19][20][21]:…”

Section: Introductionmentioning

confidence: 99%

“…The initial step in the process is thought to be OH • radical attack at the MB ring sulphur atom, which initiates a series of reactions that lead to ring opening and the loss of extended conjugation in the MB structure [13][14][15][16][17][18][19][20][21][22], thereby destroying the characteristic chromophoric unit in MB (absorption maximum at 664 nm for monomeric MB in water). The rate (r) of photo-catalytic MB degradation is described well by the Langmuir-Hinshelwood kinetic model, where k is the rate constant and K is the equilibrium constant for MB adsorption.…”

Section: Introductionmentioning

confidence: 99%

Effect of the TiO2 Crystallite Size, TiO2 Polymorph and Test Conditions on the Photo-Oxidation Rate of Aqueous Methylene Blue

et al. 2014

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This study systematically re-examines the titania-catalysed photo-oxidation of methylene blue (MB) in aqueous solution at 20°C, placing particular emphasis on the effects of TiO 2 crystallite size, TiO 2 polymorph (anatase, brookite, rutile and combinations thereof) and experimental test conditions on the rate of MB photo-oxidation. For all TiO 2 samples tested, the highest rate of MB photo-oxidation was observed at pH 6, slightly above the isoelectric point of TiO 2 (*5.8 for P25 TiO 2 ). Increasing the ionic strength at pH 6 induced MB dimer formation in solution, and lowered the rate of MB photo-oxidation by TiO 2 . For all TiO 2 polymorphs, the surface area normalised rate increased with crystallite size reflecting the corresponding reduction in surface and bulk defects (electronhole pair recombination sites). The optimum crystallite sizes were *20-25 nm for anatase and *50 nm for brookite. The photocatalytic activity of the different TiO 2 powders followed the general order P25 [ anatase [ brookite ) rutile, with the high activity of P25 TiO 2 providing strong evidence that anatase-rutile heterojunctions act as ''hotspots'' for MB photo-oxidation. Mixed phase anatase-rutile or brookite-rutile powders, each containing *5 wt% rutile, demonstrated superior area normalized photocatalytic activities for MB photo-oxidation compared to pure phase anatase or brookite powders of comparable crystallite size. Finally, deposition of Pd, Pt or Au nanoparticles decreased the activity of P25 TiO 2 for MB photo-oxidation. This paper clarifies long-standing confusion in the scientific literature about the photo-oxidation of aqueous MB over TiO 2 and M/TiO 2 (M = Pd, Pt and Au) photocatalysts.

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“…Another factor that plays an important role is the availability of hydroxyl ions at high pH value. More hydroxyl ions were produced at higher pH, which leads to an increase in the production of OH radicals, which in turn increased oxidative degradation of MB at pH = 9 [22][23][24]. For MO, degradation efficiency was increased from pH 1 to 3 and then decreased from pH 3 to 9.…”

Section: Effect Of Phmentioning

confidence: 99%

Photocatalytic Activity of Al2O3.Fe2O3 Synthesized by Ultrasonic-Assisted Mechanical Stirring

Ullah¹,

Ali²,

Hanif³

et al. 2017

Pol. J. Environ. Stud.

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Comparative study of the structural, optical and photocatalytic properties of semiconductor metal oxides toward degradation of methylene blue

Cited by 107 publications

References 24 publications

Advances in Heterogeneous Photocatalytic Degradation of Phenols and Dyes in Wastewater: A Review

Advances in Heterogeneous Photocatalytic Degradation of Phenols and Dyes in Wastewater: A Review

Effect of the TiO2 Crystallite Size, TiO2 Polymorph and Test Conditions on the Photo-Oxidation Rate of Aqueous Methylene Blue

Photocatalytic Activity of Al2O3.Fe2O3 Synthesized by Ultrasonic-Assisted Mechanical Stirring

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