Photocatalytical reduction of Cr(VI) over ZnO powder

Doménech, J.; Muñoz, Javier

doi:10.1016/0013-4686(87)85071-5

Cited by 87 publications

(31 citation statements)

References 26 publications

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“…It has also been shown that the photocatalytical reduction of Cr(VI) in aqueous suspensions of ZnO can take place under sunlight (3). The use of titanium dioxide, on the other hand, has been restricted up to now to UV light irradiation.…”

Section: Introductionmentioning

confidence: 98%

“…Cr(VI) occurs as the highly soluble oxoanions HCrO 3+ (aq) and Cr(III) hydroxo complexes, but because of the low solubility of Cr(OH) 3 (s) and other (hydr)oxides, only organic complexes may give rise to important concentrations. The standard treatment of chromium-polluted waters involves the reduction of Cr(VI) to Cr(III), which can be precipitated in neutral or alkaline solutions as Cr(OH) 3 .…”

Section: Introductionmentioning

confidence: 99%

“…The photocatalytic reduction of Cr(VI) in aqueous suspensions of semiconductors such as TiO 2 , ZnO, CdS, ZnS, and WO 3 under UV illumination has been widely studied (3)(4)(5), and con- 1 To whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Light on the Electrokinetic Behavior of TiO2 Particles in Contact with Cr(VI) Aqueous Solutions

Rodenas

Weisz

Magaz

et al. 2000

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Light on the Electrokinetic Behavior of TiO2 Particles in Contact with Cr(VI) Aqueous Solutions

Rodenas

Weisz

Magaz

et al. 2000

Journal of Colloid and Interface Science

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“…Also, the homogeneous interactions of the H 2 O 2 formed due to the H 1 ions present in water at acidic pH, add to the reduction. The H 2 O 2 is assumed to reduce Cr(VI) in a homogeneous reaction [36]. For the pH 7 and 8, very less quantities of Cr(VI) was found to reduce.…”

Section: Reduction Of Cr(vi) At Different Ph Valuesmentioning

confidence: 99%

Solar photocatalytic removal of metal ions from industrial wastewater

2008

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This article describes the photocatalytic reduction and deposition of four metal ions Cr(VI), Ni(II), Zn(II), and Cu(II) present in the wastewater from a chrome plating industry using solar energy irradiated TiO 2 . A parabolic trough reactor was used to carry out the reaction. Experiments were carried out to find an optimum dose of hole scavenger used (citric acid). The adsorption and reduction of the metal ions at different pH values was also investigated.It was observed that the solar photocatalytic process was effective in removing most of the metal ions in specific reaction conditions. Alkaline pH was found to be more suitable for removal of nickel and zinc. However, Cr(VI) reduced completely even at catalyst concentrations as low as 0.5 mg/L at pH 2. Maximum reaction was completed in the first 4 h of solar exposure.

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“…For a similar purpose in addition to TiO 2 , the following semiconductor materials are commonly used under visible or UV radiation: Ag-TiO 2 , ZnO, CdS or WO 3 . [38][39][40] The photocatalytic method is based on the reactive properties of an electron-hole pair generated in the semiconductor when irradiated by UV-Vis light having energy greater than the band-gap energy of the semiconductor.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the catalyzed photo-cold vapour generation for determination of mercury by AAS

Matusiewicz¹,

Stanisz²

2012

J. Braz. Chem. Soc.

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Nanopartículas de Ag suportadas em TiO 2 (Ag-TiO 2 ) foram usadas como catalisador na geração de vapor frio induzida por radiação UV com ácido fórmico, acoplado à absorção atômica para determinação do mercúrio total em amostras analíticas. A atividade redutora de Ag-TiO 2 foi comparada com dois catalisadores semicondutores: TiO 2 não modificado e ZnO. O efeito do tipo de catalisador, sua concentração na amostra analisada, pH da amostra, concentração do ácido fórmico e tempo de irradiação ultravioleta foi investigado. Na presença de ácido fórmico, Ag-TiO 2 foi o mais eficiente na redução de mercúrio. Nas condições experimentais otimizadas, a recuperação de mercúrio em quatro materiais de referência contendo 0,20-1,99 µg g -1 Hg foi de 95-99% dos valores certificados. O desvio padrão relativo para amostras foi igual ou melhor do que 11%. A análise de materiais de referência certificados (correspondentes a amostras ambientais e biológicas) mostrou a potencialidade do método Ag-TiO 2 -UV-CVGAAS na determinação de mercúrio em amostras analíticas no nível de ultra-traço.Nano-Ag particles loaded on TiO 2 (Ag-TiO 2 ) were used as catalyst for the UV-induced cold vapour generation with formic acid coupled to atomic absorption for determination of total mercury in analytical samples. The reducing activity of Ag-TiO 2 was compared with two semiconductor catalysts: unmodified TiO 2 and ZnO. The effect of catalyst type, its concentration in the analyzed sample, sample pH, formic acid concentration and ultraviolet irradiation time have been investigated. In the presence of formic acid, most effective in the reduction of mercury was Ag-TiO 2 . Under the optimized experimental conditions recovery of mercury in four reference materials containing 0.20-1.99 µg g -1 Hg was 95-99% of certificate values. The relative standard deviation for samples was equal to or better than 11%. Certified reference materials (corresponding to biological and environmental samples) analysis using the Ag-TiO 2 -UV-CVGAAS method revealed that it is promising for mercury determination in analytical samples at ultratrace level.

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Photocatalytical reduction of Cr(VI) over ZnO powder

Cited by 87 publications

References 26 publications

Effect of Light on the Electrokinetic Behavior of TiO2 Particles in Contact with Cr(VI) Aqueous Solutions

Effect of Light on the Electrokinetic Behavior of TiO2 Particles in Contact with Cr(VI) Aqueous Solutions

Solar photocatalytic removal of metal ions from industrial wastewater

Evaluation of the catalyzed photo-cold vapour generation for determination of mercury by AAS

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