Abstract
A mechanism for the reduction of aqueous nitrate with metal-free polypyrrole (PPy) is proposed. The activity and selectivity of the polymer has been compared to those of metal catalysts supported on polypyrrole, activated carbon or titania (TiO2). The role of formic acid (FA) and hydrogen (H2) as reductants, and carbon dioxide (CO2) as buffer of the aqueous nitrate solution is discussed and compared to the performance of PPy by itself. The ion-exchange and the redox properties of PPy are strongly affected by the oxidation state of the nitrogen moieties in the polymeric chain. This is determined by the oxidant/dopant used in the polymer synthesis (FeCl3 or K2S2O8). The degree of oxidation of PPy can also be modified by a plasma treatment of the polymer, which determines the ability of PPy to carry out the reduction of nitrate by the electrons provided by the polymeric chain and also affects the selectivity of the nitrate reduction.
Original language | English |
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Article number | 126228 |
Journal | Chemical Engineering Journal |
Volume | 403 |
Early online date | 22 Jul 2020 |
DOIs | |
Publication status | Published - 01 Jan 2021 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2020 Elsevier B.V.
Keywords
- Formic acid
- Metal-free
- Nitrate reduction
- Plasma treatment
- Polypyrrole
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry
- General Chemical Engineering
- Industrial and Manufacturing Engineering