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Advisor(s)
Abstract(s)
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=2.2·10−5M−2min−1, kH2O2 4.0·10 M ·min
= 6 3 1 and k 5.1·10 M min H
+ = 3 0.23 1 at 80 °C).
Description
Keywords
Catalytic wet peroxide oxidation Doped carbon black Kinetic model pH effect Induction period Nitrophenol
Citation
Díaz de Tuesta, Jose Luis; Quintanilla, Asuncion; Casas, Jose A.; Morales-Torres, Sergio; Faria, Joaquim L.; Silva, Adrián; Gomes, Helder (2020). The pH effect on the kinetics of 4-nitrophenol removal by CWPO with doped carbon black catalysts. Catalysis Today . ISSN 0920-5861. 356, p. 216-225