Cationic dye adsorption and separation at discrete molecular level: First example of an iron cluster with rapid and selective adsorption of methylene blue from aqueous system

Muhammad Nadeem Akhtar, I. Mantasha, M. Shahid, Murad A. Aldamen, Muhammad Khalid, Muhammad Akram

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6 Citations (Scopus)


A hexanuclear iron(iii) complex, [Fe6III(μ3-O)(edteH)2(piv)6(N3)2] (1), was prepared by the reaction of FeCl2·4H2O with N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine (H4edte) and pivalic acid (Hpiv) in the presence of NaN3 in MeCN/CH2Cl2. Its X-ray structure determination demonstrated a centrosymmetric complex with two triangular [Fe3(μ3-O)]7+ units. To verify the importance of this material, the adsorption study for 1 was performed. The use of 1 as a possible dye adsorbent was evaluated in an aqueous medium on two model dyes: methylene blue (MB) and methyl orange (MO). The results obtained indicated that 1 showed remarkable adsorption properties for MB (88.60%). This Fe cluster is the first example of a homometallic coordination cluster that presents an exciting adsorption property. The adsorption factor was that free O-H groups in the coordination cluster delivered O-H⋯π interactions through the MB dye, which was attributed to enhanced adsorption. The effects of various parameters, such as pH and temperature, were studied. The MB adsorption efficiency by adsorbent was ∼89% at neutral pH; however, for MO, it was ∼48% at the same pH. Also, MB adsorption at a higher temperature (40 °C) was ∼96%, whereas ∼61% for MO. The kinetic data provided a good confirmation of the adsorption pathways, i.e. the pseudo-second-order. Overall, this study disclosed an easy-to-prepare, stable, and reusable iron(iii) cluster as a cost-effective, eco-friendly and efficient adsorbent for hazardous water-soluble aromatic dyes. This type of adsorbents can be fine-tuned further for the desired efficiency and dye selectivity. This journal is
Original languageEnglish
Pages (from-to)1415-1422
Number of pages8
JournalNew Journal of Chemistry
Issue number3
Publication statusPublished - Jan 21 2021

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