Photocatalytic reduction of Cr(VI) on the novel hetero-system CuFe2O4/CdS

Nasrallah, Noureddine; Kebir, Mohammed; Koudri, Z.; Trari, M.

doi:10.1016/j.jhazmat.2010.10.061

Cited by 112 publications

(34 citation statements)

References 20 publications

(22 reference statements)

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“…They are important in numerous technological applications for example refractory materials [7], super hard materials [8], semiconductors [9], and high-temperature ceramics [10]. It has been widely used for various applications in catalysis [11][12][13][14], gas sensing [15,16], hydrogen production [17], lithium ion batteries [18], high density magneto-optic recording devices, magnetic refrigeration and ferro-fluids [19].…”

Section: Introductionmentioning

confidence: 99%

Up-scalable synthesis of size-controlled copper ferrite nanocrystals by thermal treatment method

Zakiyah

Saion

Al‐Hada

et al. 2015

Materials Science in Semiconductor Processing

106

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a b s t r a c tClose-packed cubic copper ferrites (CuFe 2 O 4 ) nanoparticles were synthesized using an effective thermaltreatment method directly from an aqueous solution containing copper and iron nitrates as metal precursors and poly(vinyl pyrrolidone) as a capping agent. The FTIR spectra of the calcined samples revealed the vibration bands of Fe-O and Cu-O at 315 and 535 nm respectively. The structural, morphological, optical and magnetic properties of the nanocrystal powder samples were analyzed using various characterization techniques. The powder X-ray diffraction unveiled the formation of spinel phase of CuFe 2 O 4 with the average particle size determined from TEM images increased from 24 to 34 nm at the calcination temperatures between 773 and 1173 K. The band gap calculated using Kubelka-Munk function from the UV-visible diffuse reflectance spectra decreased from 2.64 to 2.45 eV with increasing calcination temperature. The electron spin resonance (ESR) spectroscopy confirmed the presence of unpaired electrons in the calcined samples. The g-factor increased from 2.10497 to 2.57056 and the resonance magnetic field decreased from 3.11599 Â 10 À 7 to 2.55161 Â 10 À 7 A/m with increasing calcination temperature.

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Section: Introductionmentioning

confidence: 99%

Up-scalable synthesis of size-controlled copper ferrite nanocrystals by thermal treatment method

Zakiyah

Saion

Al‐Hada

et al. 2015

Materials Science in Semiconductor Processing

106

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“…The reason for this may be the decomposition of Zn 2 GeO 4 nanorods. Meanwhile, the pseudo-firstorder kinetic model for the reduction of aqueous Cr(VI) over the Zn 2 GeO 4 nanorods was also investigated [34], as expressed by ln( 0 / ) = , where is the apparent rate constant, 0 is the initial concentration of aqueous Cr(VI), and is the concentration of aqueous Cr(VI) at the reaction time . The linear plots of ln( 0 / ) versus and the rate constants are shown in Figure 5.…”

Section: Photocatalytic Experimentsmentioning

confidence: 99%

Controllable Synthesis of Zn₂GeO₄Nanorods for Photocatalytic Reduction of Aqueous Cr(VI) and Oxidation of Organic Pollutants

Liu

Jin

Shi

et al. 2015

Journal of Nanotechnology

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Zn 2 GeO 4 nanorods were successfully synthesized by a simple hydrothermal method. The composition, morphology, and optical properties of as-synthesized Zn 2 GeO 4 samples were characterized by X-ray diffraction, scan electron microscopy, and UV-vis diffuse reflectance spectra. The photocatalytic properties of Zn 2 GeO 4 nanorods were evaluated by the reduction of Cr(VI) and oxidation of organic pollutants in aqueous solution. The effects of solution pH on Cr(VI) reduction by Zn 2 GeO 4 nanorods were studied in detail. The results indicated that the efficiency of Cr(VI) reduction was highest at pH 5.96. Moreover, Zn 2 GeO 4 nanorods also showed excellent photocatalytic ability for the oxidation of organic pollutants such as rhodamine B and 4-nitrophenol.

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“…Estas reações ocorreram em 1 h, sendo o progresso da reação de redução fotoquímica de Cr(VI) acompanhado através de coletas de amostras em tempo determinados (0, 15, 30, 45 e 60 minuntos). Após as amostras foram analisadas no espectrofotômetro (Varian, Cary 100) através de medidas de absorbância, no comprimento de onda de 348 nm (Mohapatra et al, 2005;Das et al, 2006;Nasrallah et al, 2011). As absorbâncias foram relacionadas com a concentração de Cr(VI) por uma curva de calibração, de acordo com a Lei de Lambert-Beer.…”

Section: Figura 1 -Figura Esquemática Do Reator Usado Nos Experimentounclassified

Redução Fotoquímica De Cromo Hexavalente Por Álcoois Sob Radiação Uv

Machado¹,

Theisen²,

Lansarin³

2015

Anais Do XX Congresso Brasileiro De Engenharia Química

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RESUMO -No presente trabalho se estuda a redução fotoquímica de Cr(VI) por álcoois, metanol, etanol e propan-2-ol, sob radiação UV. Os experimentos foram realizados em um reator batelada de vidro com controle de temperatura e agitação, sob radiação UV. Primeiramente, avaliou-se a influência do pH inicial da solução, do volume de álcool e da concentração inicial de cromo hexavalente na redução total de Cr(VI). Os resultados obtidos permitiram concluir que a redução total de Cr(VI) é dependente da natureza do álcool, diminuindo na seguinte ordem: propan-2-ol > etanol >> metanol. Por fim, realizaram-se experimentos com um efluente industrial, originado em uma indústria de galvanoplastia, tendo sido observados altos valores de redução total de Cr(VI). INTRODUÇÃOO cromo hexavalente é tóxico para a maioria dos organismos, sendo carcinogênico e mutagênico para os animais, podendo causar irritação e corrosão na pele humana. Os metais pesados encontrados no ambiente originam-se, principalmente, da descarga inadequada de efluentes industriais (Ku e Jung, 2001), estando as empresas de curtimento de couro, tintas, corantes, materiais fotográficos, galvanoplastia, mineração, metalúrgicas e de eletrônicos, entre as possíveis fontes de cromo (Schrank et al., 2002;Mohapatra et al., 2005; Chakrabarti et al., 2009). Dentre estas, a indústria de galvanização é caracterizada pelo excessivo consumo de água e energia e pela grande geração de efluentes líquidos contendo metais pesados, tais como, cobre, níquel e cromo. Estes efluentes provêm, principalmente, do descarte das águas de enxágue das peças retiradas dos banhos eletroquímicos.O cromo ocorre na natureza em dois estados de oxidação, Cr +3 e Cr +6 ou Cr(III) e Cr(VI). O Cr(VI) é altamente solúvel, o que possibilita a contaminação de lençóis freáticos e outras fontes de água potável, sendo mais estável que o trivalente. A forma hexavalente do cromo é 100 vezes mais tóxica que a trivalente (Mohapatra et al., 2005; Das et al., 2006;Xu et al., 2006; Yang e Chan, 2009; Chakrabarti et al., 2009). Por outro lado, o cromo trivalente é facilmente precipitado e não apresenta toxicidade, sendo considerado um elemento essencial para o metabolismo humano, em níveis controlados (Kim et al., 2002;Mohapatra et al., 2005).O tratamento convencional para águas residuais contendo Cr(VI) é a redução com sulfito de sódio ou metabissulfito. Este método, no entanto, apresenta alguns problemas: exige um excesso de Área temática: Engenharia Ambiental e Tecnologias Limpas 1

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Photocatalytic reduction of Cr(VI) on the novel hetero-system CuFe2O4/CdS

Cited by 112 publications

References 20 publications

Up-scalable synthesis of size-controlled copper ferrite nanocrystals by thermal treatment method

Up-scalable synthesis of size-controlled copper ferrite nanocrystals by thermal treatment method

Controllable Synthesis of Zn₂GeO₄Nanorods for Photocatalytic Reduction of Aqueous Cr(VI) and Oxidation of Organic Pollutants

Redução Fotoquímica De Cromo Hexavalente Por Álcoois Sob Radiação Uv

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Photocatalytic reduction of Cr(VI) on the novel hetero-system CuFe2O4/CdS

Cited by 112 publications

References 20 publications

Up-scalable synthesis of size-controlled copper ferrite nanocrystals by thermal treatment method

Up-scalable synthesis of size-controlled copper ferrite nanocrystals by thermal treatment method

Controllable Synthesis of Zn2GeO4Nanorods for Photocatalytic Reduction of Aqueous Cr(VI) and Oxidation of Organic Pollutants

Redução Fotoquímica De Cromo Hexavalente Por Álcoois Sob Radiação Uv

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Controllable Synthesis of Zn₂GeO₄Nanorods for Photocatalytic Reduction of Aqueous Cr(VI) and Oxidation of Organic Pollutants