Modeling RSM of photocatalytic treatment of Acid Red 18 pollutant using ZnO--Cr nano-photocatalyst, kinetic studies, and energy management.

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From: Canadian Journal of Chemistry(Vol. 100, Issue 4)
Publisher: NRC Research Press
Document Type: Report
Length: 5,183 words
Lexile Measure: 1510L

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Abstract :

The ZnO-Cr nano-photocatalyst was synthesized using a microwave-assisted solution combustion method and applied for the photodegradation of the organic pollutant Acid Red 18 (AR18). The synthesized nano-photocatalyst was characterized by XRD, FESEM, EDX, and FTIR methods. To reach the optimal condition of the treatment, the response surface methodology was used in the central composite design model. The amount of nano-photocatalyst, pH of the solution, and initial concentration of the pollutant were optimized. The polynomial 3-degree model was fitted to the photodegradation data, and the correlation coefficients of the model showed an interaction between the parameters. Optimization of the polynomial model for pollutant treatment was investigated under the same conditions, and the comparison of the observed and predicted treatment models showed a low difference in decolorization. The intermediates were identified by liquid chromatography/mass spectrometry. A kinetic study showed that the first-order kinetic constant for the degradation of pollutant concentrations from 10 to 30 mg [L.sup.-1] changed from 0.0178 to 0.0058 [min.sup.-1]. Finally, economic evaluation and energy management of the process showed that the decolorization process was more economical at low pollutant concentrations. Key words: microwave-assisted solution combustion synthesis, nano-photocatalyst, response surface methodology. Nous avons synthetise un nanophotocatalyseur a base de ZnO-Cr a l'aide d'une methode de combustion en solution assistee par micro-ondes et nous l'avons applique a la photodegradation du contaminant organique rouge acide 18. Nous avons caracterise le nanophotocatalyseur ainsi prepare par diffraction des rayons X (DRX), microscopie electronique a balayage a emission de champ (MEBEC), spectroscopie de rayons X a dispersion d'energie (EDX) et spectroscopie infrarouge a transformee de Fourier (FTIR). Pour atteindre de maniere exacte les conditions optimales de traitement, nous avons employe la methode des surfaces de reponse selon le modele de plan composite centre. Nous avons optimise les parametres a considerer, soit la quantite de nanophotocatalyseur, le pH de la solution et la concentration initiale du contaminant. Les donnees de photodegradation ont ete ajustees par regression polynomiale de degre 3, et les coefficients de correlation du modele ont montre une interdependance entre les parametres. Nous avons explore l'optimisation du modele polynomial pour le traitement des contaminants dans les memes conditions, de sorte que la difference de decoloration soit faible lorsque lon compare les donnees experimentales et calculees a partir du modele de traitement. Nous avons identifie les intermediaires par une analyse en chromatographie liquide couplee a la spectrometrie de masse. L'etude cinetique a revele une constante cinetique de premier ordre, qui a varie de 0,0178 a 0,0058 [min.sup.-1], pour la degradation des contaminants a des concentrations de 10 a 30 [mgs.sup.2][L.sup.-1]. Enfin, l'evaluation economique et la gestion energetique du processus ont montre que la decoloration est plus economique a de faibles concentrations du contaminant. [Traduit par la Redaction] Mots-cles : synthese par combustion en solution assistee par micro-ondes, nanophotocatalyse, methode des surfaces de reponse.

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Gale Document Number: GALE|A700235415