Extraction, preconcentration and spectrometric determination of Al (III) and Cr (III) ions using modified MnFe₂O₄ nanoparticles as an efficient adsorbent

Abstract

An efficient and reusable adsorbent, namely 3-mercaptopropionic acid modified tetraethyl orthosilicate (TEOS) grafted MnFe₂O₄ nanoparticles (MPA-TEOS-MnFe₂O₄NPs) was synthesized and used for the extraction and preconcentration of trace amount of Al (III) and Cr (III) ions in water samples. MnFe₂O₄NPs were prepared by chemical co-precipitation of manganese (II) and iron (III) salts in alkaline medium and then, modified by TEOS to create an inert layer preventing nanoparticle agglomeration. The TEOS-MnFe₂O₄NPs were then modified with MPA to produce an adsorbent with carboxylic acid functional groups which have tendency to hard metal ions such as Al(III) and Cr (III). The prepared adsorbent was characterized by SEM, XRD, VSM and FT-IR techniques. The Al (III) and Cr(III) ions were measured by graphite furnace and flame atomic absorption spectrometric techniques, respectively. Various factors affecting extraction/desorption efficiency of target ions were investigated and analytical characteristics of the method were determined and detection limits of 0.5 and 0.2 ng mL^-1 with preconcentration factor of 69 and 72 were obtained for Al (III) and Cr(III) ions, respectively. The results revealed that the adsorbent has high capacity and good reusability for extraction/preconcentration of target metal ions in tap and drinking water samples.