Response surface methodology applied for Orange II photocatalytic degradation in TiO<sub>2</sub> aqueous suspensions

Smaranda, Camelia; Caliman, Florentina Anca; Gavrilescu, Maria; Creţescu, Igor; Cojocaru, Corneliu; Poulios, Ioannis

doi:10.1002/jctb.1973

Cited by 40 publications

(32 citation statements)

References 40 publications

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“…Finally, the response functions reported in the literature [17][18][19][20] for MY, AO7, RR120, and RB19 are shown in Tab. 4.…”

Section: Symbolsmentioning

confidence: 98%

“…1a)), whose photocatalytic degradation has been studied by several authors [7,10]. After addition of TiO 2 particles to MeO solutions, the dye is adsorbed mainly through the sulfonate group since, under acidic conditions, the photocatalyst surface is positively charged (the zero point of charge of TiO 2 suspensions is pH zpc = 5.6-6.8) [18,20,[26][27][28] and attractive forces between the protonated Ti-(OH 2 ) + surface groups and the dye molecules are operable [29].…”

Section: Azo Dyesmentioning

confidence: 99%

“…As previously stated [10,70,71], the initial pH strongly influences the adsorption of MeO molecules onto the TiO 2 surface, which is essential for the photodecomposition of the dye. This is so because the titania surface consists of amphoteric zones that may become positively or negatively charged depending on the pH of the solution [20,65]. When pH < pH of zero charge (pH pzc ), the catalyst is in the form TiOH 2 + , whereas for pH > pH pzc it is negatively charged (TiO -).…”

Section: Methyl Orangementioning

confidence: 99%

“…Subsequent illumination of the aqueous MeO/TiO 2 suspension by UV light causes a relatively rapid discoloration of the solution with time, which is mainly due to the degradation of the chromophoric group (azo group) responsible for the characteristic color of the azo dye [9,20]. It is a well-known fact that, when the catalyst is exposed to UV radiation with light energy greater than its band gap energy (E g = 3.14 eV), electrons are promoted from the valence band to the conduction band, resulting in the formation of an electron-hole pair.…”

Section: Azo Dyesmentioning

confidence: 99%

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Photocatalytic Discoloration of Dyes: Relation between Effect of Operating Parameters and Dye Structure

Camarillo

Rincón

2011

Chem Eng & Technol

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The process of TiO 2 /UV photocatalytic discoloration of wastewaters containing organic dyes is influenced by a number of variables. In this paper, the effects of some of these parameters, i.e., mass of catalyst, initial dye concentration, and pH, were related to the structural nature of the dyes investigated, azo and anthraquinone dyes, two families that are representative of about 75 % of the dyes marketed nowadays. Both bibliographical and own experimental data were used to analyze and discuss the photocatalytic discoloration in terms of dye structure and degradation pathways. It is shown that azo dyes (Methyl Orange, Metanil Yellow, Acid Orange 7, and Reactive Red 120) are more easily discolored than Reactive Blue 19 (anthraquinone dye), due to the higher molecular stability of the latter. It is also shown that azo dye discoloration is more influenced by the initial dye concentration, whereas recalcitrant anthraquinone dyes (Reactive Blue 19) mainly demand for basic pH values to generate enough OH . radicals. Concerning TiO 2 loading, both the bibliographical and current research data showed no effect of this variable in the experimental range analyzed.

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“…Finally, the response functions reported in the literature [17][18][19][20] for MY, AO7, RR120, and RB19 are shown in Tab. 4.…”

Section: Symbolsmentioning

confidence: 98%

Section: Azo Dyesmentioning

confidence: 99%

Section: Methyl Orangementioning

confidence: 99%

Section: Azo Dyesmentioning

confidence: 99%

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Photocatalytic Discoloration of Dyes: Relation between Effect of Operating Parameters and Dye Structure

Camarillo

Rincón

2011

Chem Eng & Technol

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“…Among the azo dyes the orange II can be considered as a model compound for oxidative degradation studies and it has been investigated extensively on different catalysts [4,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic degradation of Orange II by titania addition to sol–gel glasses

Gargori

Llorach

Vicent

et al. 2009

J Sol-Gel Sci Technol

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Glasses with SiO 2 -CaO-ZnO-B 2 O 3 -K 2 O-Al 2 O 3 composition modified by addition of titania (3, 5, 12 and 20% w) have been prepared by sol-gel method. The obtained gels were aged, dried and fired at 600ºC/1h in order to stabilise the glass. The resulting fired powders were characterised by UV-Vis-NIR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Their photocatalytic capacity on the degradation of orange II dye has been studied. The XRD and TEM results indicate that system is amorphous with a nanostructured microstructure. From UV-Vis-NIR results the band gap calculated is around 3.5 eV for all samples. Photoactivity of powders depends on amount of titania in glass composition and the surface area of prepared samples. The sample with highest surface area and lowest addition of titania (3% w. sample) shows similar activity than commercial anatase used as reference.

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Improvement of caffeic acid biotransformation into para‐hydroxybenzoic acid by Candida albicans CI‐24 via gamma irradiation and model‐based optimization

Elleboudy

Elkhatib

Yassein

et al. 2021

Biotech and App Biochem

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Para‐hydroxybenzoic acid (PHBA) has great potential in biological applications due to its putative antiviral activity against SARS‐CoV‐2 and its antimicrobial activity in the face of the radically increasing number of multidrug‐resistant pathogens. This is in addition to its antimutagenic, anti‐inflammatory, antioxidant, hypoglycemic, antiestrogenic, and antiplatelet aggregating activities. In this study, an approximate sixfold increase in the production of PHBA was achieved via biotransformation of caffeic acid by Candida albicans. The improvement was performed in two steps: first, through mutation by gamma irradiation (5 KGy dose), resulting in the recovery of a mutant (CI‐24), which produced approximately triple the amount of PHBA produced by the wild‐type isolate. Then, biotransformation by this mutant was further optimized via response surface methodology model‐based optimization. The maximum PHBA production (7.47 mg/mL) was obtained in a fermentation medium composed of 1% w/v yeast extract as a nitrogen source, with an initial pH of 6.6, incubated at 28 °C at an agitation rate of 250 rpm. To further enhance the performance and economics of the process, cells of the CI‐24 mutant were immobilized in calcium alginate beads and could retain an equivalent biotransformation capacity after three successive biotransformation cycles.

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Response surface methodology applied for Orange II photocatalytic degradation in TiO₂ aqueous suspensions

Cited by 40 publications

References 40 publications

Photocatalytic Discoloration of Dyes: Relation between Effect of Operating Parameters and Dye Structure

Photocatalytic Discoloration of Dyes: Relation between Effect of Operating Parameters and Dye Structure

Photocatalytic degradation of Orange II by titania addition to sol–gel glasses

Improvement of caffeic acid biotransformation into para‐hydroxybenzoic acid by Candida albicans CI‐24 via gamma irradiation and model‐based optimization

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Response surface methodology applied for Orange II photocatalytic degradation in TiO2 aqueous suspensions

Cited by 40 publications

References 40 publications

Photocatalytic Discoloration of Dyes: Relation between Effect of Operating Parameters and Dye Structure

Photocatalytic Discoloration of Dyes: Relation between Effect of Operating Parameters and Dye Structure

Photocatalytic degradation of Orange II by titania addition to sol–gel glasses

Improvement of caffeic acid biotransformation into para‐hydroxybenzoic acid by Candida albicans CI‐24 via gamma irradiation and model‐based optimization

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Response surface methodology applied for Orange II photocatalytic degradation in TiO₂ aqueous suspensions