The pH effect on the kinetics of 4-nitrophenol removal by CWPO with doped carbon black catalysts

• Type: Article in International Scientific Journal
• Date: 2019

Authors

Jose L. Diaz de Tuesta (Author) Other; Asuncion Quintanilla (Author) Other; Jose A. Casas (Author) Other; Sergio Morales-Torres (Author) Other; Joaquim L. Faria (Author) FEUP; Adrián M.T. Silva (Author) FEUP; Helder T. Gomes (Author) Other

Journal

Title: Catalysis Today

Pages: 1-10

ISSN: 0920-5861

Publisher: Elsevier

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Other information

Authenticus ID: P-00R-1Q9

DOI: 10.1016/j.cattod.2019.08.033

Abstract (EN): P, B and N-doped carbon blacks prepared with H3PO4, urea and H3BO3 were tested as catalysts in the wet peroxide oxidation of a concentrated 4-nitrophenol (4-NP) model solution (C4-NP = 5 g·L−1). The highest catalytic activity was found for P-doped carbon black (complete removal of 4-NP after 4 h at 80 °C, Ccat = 2.5 g·L−1, CH2O2=17.8 g·L−1 and initial pH 3, whereas 44-19% removals were reached with the other catalysts). That was ascribed to the strongest acidity (pHPZC = 3.5) and hydrophilic character of the catalyst. Initial pH affected the oxidation, allowing to increase strongly the conversion of 4-NP with the P-doped catalyst decreasing the initial pH from 4 to 2 (4-NP removal from 20% to 99% after 8 h of reaction time at 50 °C, Ccat = 2.5 g·L−1 andCH2O2=17.8 g·L−1). An autocatalytic-power-law kinetic model was developed to predict the observed induction period and the dependence on the pH of the 4-NP oxidation, H2O2 consumption and pH evolution (k4-NP = 2.2·10−5 M−2 min−1, kH2O2=4.0·10−6 M−3·min−1 and kH+=5.1·10−3 M−0.23 min−1 at 80 °C). © 2019 Elsevier B.V.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10