Removal of toxic nitrate ions from drinking water using conducting polymer/MWCNTs nanocomposites

• Published in: Iranian polymer journal Vol. 22; no. 2; pp. 85 - 92
• Main Authors: Nabid, Mohammad Reza, Sedghi, Roya, Sharifi, Roghayeh, Oskooie, Hossein Abdi, Heravi, Majid M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2013
• Subjects: Ceramics; Chemistry; Chemistry and Materials Science; Composites; Glass; Natural Materials; Original Paper; Polymer Sciences; Nitrate removal; Drinking water; Ion-exchange; PANI/MWCNTs nanocomposite; Conducting polymer/MWCNTs nanocomposites
• ISSN: 1026-1265; 1735-5265
• DOI: 10.1007/s13726-012-0106-2

New application of conducting polymers as stable nanocomposites for nitrate ion exchange materials in water and wastewater treatment and for environmental protection is introduced in this work. The nanocomposites of multi-walled carbon nanotubes (MWCNTs) with different polymers such as: polyaniline (PANI), polypyrrole (PPY), poly(1,8-diaminonaphthalene) [P(1,8-DAN)] and poly(2-vinylpyridine) (P2VP) were synthesized with different dopants as effective and reusable nanocomposites for nitrate removal from drinking water. Nitrate anions at toxic concentrations were removed from water using ion exchange mechanism without any toxic byproducts. The obtained results demonstrate that effective ion exchange occurs between NO 3 − and Cl − . There are some protonated heteroatoms in polymer chains that are bonded with anions of dopants and their counter ions in nanocomposites. These dopant anions on the =NH + – groups of polymers can be exchanged with NO 3 − in water. Adsorption of NO 3 − on polymer/MWCNTs nanocomposites showed dependency to some parameters. Different experimental parameters such as pH and temperature of the sample, polymers dopant, and the ratio of polymer to MWCNTs in nanocomposites affect the amount of nitrate removal. The highest removal efficiency was achieved at 1.20 g L −1 of PANI/MWCNTs (3:1) nanocomposite, pH = 6.5 and ambient temperature. After five successive cycles of nitrate removal, this parameter was still up to 70 % compared to the first run (up to 80 %).