Mineralization of formic acid from catalytic nitrate reduction effluent by UV-based and electrochemical processes. Issue 5 (October 2020)

• Record Type: Journal Article
• Authors: Zoppas, Fernanda Miranda; da Silva, Salatiel Wohlmuth; Beltrame, Thiago Favarini; Marchesini, Fernanda Albana; Bernardes, Andréa Moura; Miró, Eduardo
• Is Part Of: Journal of environmental chemical engineering. Volume 8:Issue 5(2020)
• Publication Date: 2020-10
• Subjects: Formic acid -- Catalytic nitrate reduction effluent -- UV-based process -- Electrochemical oxidation -- Mineralization -- Advanced oxidation processes; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2020.104127
• Languages: English
• ISSNs: 2213-2929

Abstract

Highlights: UV-based and electrochemical processes were evaluated to FA mineralization. Only UV-based processes are unable to FA mineralization. Nitrate photolysis generate O 2 - and H O, contributing positively in FA mineralization. The generation of O 2 - and H O is a rate-limiting-step. Electrochemical process plays the most important role in FA mineralization. Abstract: In this work, UV-based and electrochemical processes were proposed for formic acid (FA) mineralization, from an effluent generated on the nitrate catalytic reduction reaction. The results show that although direct photolysis (DP) does not have the ability to mineralize FA, heterogeneous photocatalysis (HP), photo-assisted electrochemical oxidation (PEO) and electrochemical oxidation (EO) have. In fact, it has been shown that FA mineralization is governed by the electrochemical process. When nitrate was added in the FA solution, all process exhibited an increase in FA mineralization, mainly for DP. For UV-based process, this fact can be linked to the nitrate photolysis generating hydroxyl radicals ( H O ). On the other hand, the mineralization increase observed on the EO process, is associated with the increase in charge transfer, considering that the generation of oxidants is a rate-limiting-step, showing pseudo-zero-order constants for DP and HP, and pseudo-first-order for PEO and EO. The best results of FA mineralization with the smallest energy consumption was obtained by the electrochemical process. Besides, EO was not negatively influenced by the addition of nitrate.