p-Nitrophenol degradation by Fenton's oxidation in a bubble column reactor

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Carmen Rodrigues (Author) FEUP; Ricardo A.C. Borges (Author) Other; Vanessa N. Lima (Author) Other; Luis Madeira (Author) FEUP

Journal

Title: Journal of Environmental Management

Vol. 206

Pages: 774-785

ISSN: 0301-4797

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 9 Citations

ISI Web of Science

Scopus - 34 Citations

Associated Projects

LEPABE - Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia

Other information

Authenticus ID: P-00N-8Q6

DOI: 10.1016/j.jenvman.2017.11.032

Abstract (EN): The use of the air stream aimed to provide perfect mixing in the liquid phase, which was successfully achieved and checked experimentally; there were no concentration gradients along the column, even at the lowest air flow rate used (Q ¼ 1 mL/min at room temperature and atmospheric pressure). The effect of the operating variables was assessed, and a total reduction of PNP was reached, as well as mineralization of 49.2%, oxidant consumption of 90.3%, and with an efficiency of use - hH2O2 - of 0.09 mg C/mg H2O2, under the best operating conditions found - Q ¼ 1 mL/min, [H2O2] ¼ 1.6 g/L, [Fe2+] = 80 mg/L, pH = 3.0 and T = 22e24 C - (after 120 min of reaction). Following this, various strategies were developed for improving the mineralization rate; it was found that the addition of H2O2 every 5 min and readjusting the pH after 30 min of reaction allow the attainment of a much higher TOC removal (75.1%) and efficiency of oxidant use (hH2O2 ¼ 0.17 mg C/mg H2O2) with less oxidant. A reaction mechanism was proposed, based on intermediates identified that include p-nitrocatechol - PNC, p-benzoquinone - PB, hydroquinone - HQ - and carboxylic acids (oxalic, maleic and fumaric). Since the performance achieved in the BCR was good, and very similar to that obtained in a conventional batch reactor, it was possible to verify the efficacy of carrying out the Fenton process in this reactor configuration, which in our future work will focus on the treatability of industrial effluents.

Type (Professor's evaluation): Scientific