Photocatalytic degradation of methylene blue on nanocrystalline TiO2: Surface mass spectrometry of reaction intermediates

Gnaser, Hubert; Savina, M. R.; Calaway, W. F.; Tripa, C. E.; Veryovkin, I. V.; Pellin, Michael J.

doi:10.1016/j.ijms.2005.07.003

Cited by 127 publications

(97 citation statements)

References 34 publications

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“…The fragmentation of both MB + and [MB + H] +• ions occurs via the CH 2 fragment loss (ions with m/z 270 and 271, respectively), which is in perfect accordance with the previously published data on the methylene blue LDI from the nanocrystalline TiO 2 support. [18] The most significant fragmentation is observed from PS-OX, less significant from PS-H and the least from PS-SO 3 H platform. To get an insight into the methylene blue desorption/ionization mechanisms, intensities of the ion desorption were monitored versus the energy of laser pulse (Fig.…”

Section: Dios Mass Spectra Of Ionic Dyesmentioning

confidence: 93%

“…The reduction/protonation process requires lower laser energy (over 5 µJ/pulse) than direct desorption of MB + (over 13 µJ/pulse). Previously, the reduction/protonation of the methylene blue was observed in FAB MS, [19] in LDI MS from nanocrystalline TiO 2 support [18] and in MALDI and DIOS MS. [20] As it was shown in Kazakoff et al, [19] the reduction/protonation of MB + may occur via the electron transfer and protonation (Eqns 3 and 4) or via the direct addition of H…”

Section: Desorption/ionization Mechanismsmentioning

confidence: 93%

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Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyes

et al. 2009

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Desorption/ionization on silicon (DIOS) mass spectra of model ionic dyes methylene blue (MB+Cl-) and methyl orange (Na+MO-) were studied using p+ type-derived porous silicon (PS) free layers. As-prepared PS (PS-H), the PS thermally oxidized at 300 degrees C (PS-OX), PS with chemically grafted cation-exchanging alkylsulfonic acid (PS-SO(3)H) and anion-exchanging propyl-octadecyldimethylammonium chloride (PS-ODMA+Cl-) groups was tested as ionization platforms. Two mechanisms of the methylene blue desorption/ionization were found: (1) the formation of [MB + H]+* ion due to the reduction/protonation of MB+, which is predominant for PS-H and PS-OX platforms and (2) direct thermal desorption of the MB+ cation, prevailing for PS-SO3H. The fragmentation of the cation is significantly suppressed in the latter case. The samples of PS-SO3H and PS-ODMA+ Cl- efficiently adsorb the dyes of the opposite charge from their solutions via the ion-exchange. Consequent DIOS MS studies allow to detect only low fragmented ions (MB+ and MO-, respectively), demonstrating the potential of the ion-exchange adsorption combined with DIOS MS for the analysis of ionic organic compounds in solutions.

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Section: Dios Mass Spectra Of Ionic Dyesmentioning

confidence: 93%

Section: Desorption/ionization Mechanismsmentioning

confidence: 93%

Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyes

et al. 2009

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“…Due to degradation of MB, presence of demethylated molecules such as Azure A, Azure B and C, and thionine having mass to charge ratios of 270, 256, and 228, respectively are reported in literature. 51,52 In the degradation of MB, the S-Cl bond broke rst due to low bond disassociation energy, leading to the detection of Cl À at the beginning of the reaction. 53 Phenyl thiophene present in the form of protonated phenyl thiophene having m/z ¼ 138 was also detected in this study.…”

mentioning

confidence: 99%

Stabilized fabrication of anatase-TiO₂/FeS₂ (pyrite) semiconductor composite nanocrystals for enhanced solar light-mediated photocatalytic degradation of methylene blue

et al. 2018

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“…Phenylsulfinate ion at 140 m/z was also observed photocatalytic degradation of methylene blue on nanocrystalline TiO2 (Gnaser et al, 2005).…”

Section: 3paracetamol Residues In Treated Samples By Ag Doped Tio2mentioning

confidence: 86%

Decolarization of methylene blue and methyl orange with Ag doped TiO2 under UV-A and UV-Visible conditions: process optimization by response surface method and toxicity evaluation

2016

Global NEST Journal

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MB decolarization with pure TiO2 and Ag doped TiO2 based photocatalytic system were investigated under UV-A and UV-Visible conditions. Different ratios of Ag were used as metal dopant. 1% Ag-TiO2 increased the decolorization efficiencies of MB and MO dyes, also the kapp constant enhanced under UV-A and UVVisible conditions. A central composite analysis showed the effect of initial dye concentration, pH, Ag-TiO2 concentration and the reaction time of photocatalytic process under UV-A irridation in both dyes. The photocatalytic degradation pathways of both dyes by Ag doped TiO2 catalyst were obtained in this study. According to these results, the application of Ag-TiO2 catalyst are proved to be more effective than pure TiO2 catalyst for both MB and MO removal. The toxicity test of Daphnia Magna shows that non toxic wastewater discharge to the receiving environment could be possible with photocatalytic degration by Ag-TiO2 catalyst.

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Photocatalytic degradation of methylene blue on nanocrystalline TiO2: Surface mass spectrometry of reaction intermediates

Cited by 127 publications

References 34 publications

Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyes

Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyes

Stabilized fabrication of anatase-TiO₂/FeS₂ (pyrite) semiconductor composite nanocrystals for enhanced solar light-mediated photocatalytic degradation of methylene blue

Decolarization of methylene blue and methyl orange with Ag doped TiO2 under UV-A and UV-Visible conditions: process optimization by response surface method and toxicity evaluation

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Photocatalytic degradation of methylene blue on nanocrystalline TiO2: Surface mass spectrometry of reaction intermediates

Cited by 127 publications

References 34 publications

Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyes

Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyes

Stabilized fabrication of anatase-TiO2/FeS2 (pyrite) semiconductor composite nanocrystals for enhanced solar light-mediated photocatalytic degradation of methylene blue

Decolarization of methylene blue and methyl orange with Ag doped TiO2 under UV-A and UV-Visible conditions: process optimization by response surface method and toxicity evaluation

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Stabilized fabrication of anatase-TiO₂/FeS₂ (pyrite) semiconductor composite nanocrystals for enhanced solar light-mediated photocatalytic degradation of methylene blue