کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4985021 | 1454501 | 2017 | 9 صفحه PDF | دانلود رایگان |
Three different conducting polymers, polythiophene (PT), polypirrol (PPY) and polyaniline (PANI) have been synthesized via oxidative chemical polymerization in aqueous media, in such a way that the synthesis protocol did not involve any toxic solvents. They have been tested in the abatement of nitrates from an aqueous solution without the need of any metal catalyst. The N-containing polymers (PANI and PPy) were able to remove nitrates to a level that accomplishes the European legislation requirements; however, the nature of each polymer greatly influenced the process mechanism. Whereas ion exchange between Clâ and SO42â counter-ions in the polymer and NO3â from water is the main responsible for the effective nitrate removal in PANI, as assessed by FTIR and XPS analyses, the nitrate removal mechanism on PPy is based in an electron transfer from the polymer to nitrate through N sites located in the pyrrolic ring. On the other hand, PT was not able to exchange nitrate unless it was synthesized with FeCl3 as oxidant/dopant and an anionic surfactant (sodium dodecyl sulfate -SDS-) is used. In that case, the electrostatic attraction between sulfate (OSO3â) groups from the surfactant and Fe3+ ions from FeCl3 produced the anchoring of Clâ to the oxidized PT growing chain, this favoring ion exchange with nitrate in the aqueous solution, followed by a redox process.
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Journal: Journal of Colloid and Interface Science - Volume 494, 15 May 2017, Pages 98-106