Tannic Acid for Simple and Highly Selective Visual Detection of Iron (II) and (III) Ions from Different Aqueous Environments


YILDIZ M., ŞAHİNER N.

Water, Air, and Soil Pollution, vol.232, no.5, 2021 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 232 Issue: 5
  • Publication Date: 2021
  • Doi Number: 10.1007/s11270-021-05116-0
  • Journal Name: Water, Air, and Soil Pollution
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, ABI/INFORM, Agricultural & Environmental Science Database, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), Artic & Antarctic Regions, BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Chimica, Compendex, EMBASE, Environment Index, Geobase, Greenfile, Pollution Abstracts, Veterinary Science Database, Civil Engineering Abstracts
  • Keywords: Aqueous environments, Colorimetric sensors, Fe2+ and Fe3+ cations, Tannic acid (TA)
  • Çanakkale Onsekiz Mart University Affiliated: Yes

Abstract

Tannic acid (TA) was employed as a novel colorimetric iron ion sensor. TA showed highly selective recognition for only Fe2+ and Fe3+ among a range of tested metal ions such as Cr3+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Hg2+, and Pb2+. In the presence of these metal cation solutions, only Fe2+ and Fe3+ solutions underwent impressive color change detectable with the naked eye from colorless to purple and gray, respectively. Surprisingly, TA behaves as a highly selective sensor upon chemical oxidation of iron (Fe2+ and Fe3+) cations. In addition, various sensor applications of TA were performed. For this, TA-impregnated silica gel, alumina oxide sheet, and filter paper were used. Each test strip showed very high selectivity for iron ions. The detection limit of the sensor for Fe2+ and Fe3+ was found to be 1.0 × 10−6 M, and the association constant Ka was determined as 4.05 × 104 M−1 and 1.80 × 107 M−1. The order of ion binding power was determined to be Fe3+ > Fe2+ by UV-Vis spectroscopy. These discernable color changes due to the complexion of TA with Fe2+ and Fe3+ demonstrated the utilization of TA to selectively detect these metal cations. Graphical abstract: The use of tannic acid as a complexing agent that can detect Fe (II) and Fe (III) metal ions in environmental waters by colorimetry and spectrophotometry.[Figure not available: see fulltext.]