Influence of organic matter formed during oxidative processes in the catalytic reduction of nitrate

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Santos, ASGG (Author) Other; Restivo, J (Author) Other; Orge, CA (Author) Other; Manuel Fernando R Pereira (Author) FEUP; O.S.G.P. Soares (Author) FEUP

Journal

Title: Journal of Environmental Chemical Engineering

Vol. 9

ISSN: 2213-3437

Publisher: Elsevier

Indexing

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Other information

Authenticus ID: P-00T-X8J

DOI: 10.1016/j.jece.2021.105545

Abstract (EN): The application of the catalytic reduction process to remove nitrate formed during the ozonation process of organic compounds in water was assessed to study the possibility of integrating both technologies to perform a simultaneous removal of organic and inorganic species present in water. Single ozonation of two model organic compounds (4-nitrobenzaldehyde and ampicillin) was performed in order to decompose the parent organic molecule. After the treatment with ozone, the obtained solution was forwarded to a catalytic reduction process, to convert nitrate (NO3-) formed during the previous process. Organic matter present in a solution after the treatment with ozone proved to negatively affect the efficiency of nitrate reduction due to possible adsorption on the catalyst active sites, inhibiting the conversion process. However, for solutions with a low concentration of organic matter (around 2 mg L-1) it was possible to achieve NO3- conversion, although not complete during the reaction time used, and with high selectivity for ammonia formation. Several experiments were carried out to understand the effect of the organic matter on the catalyst performance, allowing to conclude that its adsorption on the catalyst surface would be the main cause of its deactivation. This issue was overcome by the application of bimetallic catalysts with high metal content (5% Pd-2.5% Cu) in different supports in the presence of organic matter, and an improvement in NO3- conversion was achieved, meaning that the presence of organic matter in solution does not completely deactivate the catalyst.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11